BAC Forum
General Boards => Technical Support => Topic started by: Dennis Belfils on May 09, 2016, 08:39:16 PM
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Our Hydro-Hot is not keeping up with even a short shower on diesel. Looked around at the posts of Hydro-Hot woes & it is quite extensive. Don't know where the mixing valve or stir pump are. Any suggestions?
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Dennis,
At this web site you can download your model number service manual which has a parts locater for each model. http://www.aquahot.com/Library.aspx
This site is good for service help and parts: http://www.parts.rvhydronicheaterrepair.com/
Steve
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Dennis, is the diesel burner running when you run out of hot water? There are several people in the club that are highly experinced on the hydro hot so I am confident they will chime in. The stir pump is on the lower right side of the burner assembly. About the size of a d cell flashlight around 4 to 5 inches long. The temp regulator can be seen with a mirror at the rear center portion of the unit. It has a round plastic knob but I don't recommend adjusting it until you are assured everything else is OK. You can also go to Aqua hots web site and search for the archived manuals for your model. It will help if you give us the model of your unit. Good luck.
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Yes, am running out of HW while using diesel. Model is HHE-200 50K BTU
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Dennis,
I had a similiar issue. Water would start Hot, but cool down during shower to warm.
My issue turned out to be a bad Control Thermostat which I replaced and problem was solved.
Go to Hydronic Heating website. Lots of good information there on Forum.
Other possible causes are as someone already mentioned, Stir Pump and Mixing Valve.
http://www.rvhydronicheaterrepair.com/
Darrell Terry
2004 Monterey
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That's what we are experiencing. Where is the Stat located?
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That's what we are experiencing. Where is the Stat located?
Every model is different. Get the books from the links Steve posted.
If my experience of 12 years in a Monterey means anything, you will spend more effort and time keeping your HydroHot running than anything else. You need the books and need to understand how it works. It is the most complex heating system in anything we'll ever live in.
We had shower problems twice for extended periods. The last time, two well known factory certified techs missed the diagnosis. The third, John Carrillo, found it. First, he explained the trouble shooting was difficult and time consuming. Every component, including the thermostats, had to be checked first. If everything else was working, the last component would be the "stir pump" which could only be "tested" by replacing it. He did, and the shower returned to normal. The original stir pumps in '04 were too small and had a short life. It was replaced once at about year 5. The third was bigger and beefier, but I think the new owner has replaced that one too!
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Dennis,
I have an HHE-500-07M. The Control Thermostat is located just above the Burner Head on mine. It looks like a brass nut with two wires coming out.
This was the simplest, cheapest, and easiest of the 3 common causes for fluctuating hot water so I chose to replace this first.
You will need to drain about 6 gallons of antifreeze from the tank before removing the thermostat.
I used a drill with a small circular pump to siphon out and filled empty plastic jugs so I could replace the antifreeze after I R&R'd the thermostat.
I purchased my Control thermostat from Roger Berke at Hydronics Heating.I believe the thermostat was about $68. I also borrowed a modified socket from him to facilitate removal and replacement.
He will credit you when you return the part or you can purchase if you like.
If you purchase from Roger he will also send you instructions.
Hope this helps.
Darrell Terry
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Dennis,
The mixing valve can cause the problem you are describing. While another responder noted you should not adjust it (I agree) if it is intermittant, turning the adjustment "knob" back and forth will sometime free up the crud inside and get it working again. Just be sure to set the knob back to it's original position.
Steve
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I run out of hot water in electric mode. When I first feel it cooling off I give the tap a slight nudge towards hotter and it gets hot again but this cools down after 30 seconds or so. I just figured it was because the supply tank was small. I don't take long leisurely showers either. It's been like that since I bought it December 2014 and the last thing the dealer worked on before I took delivery was getting the diesel hot water to work so I figure the system was up to spec. Maybe not?
MJ
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Electric won't keep up with uses as demanding as a shower. Yours is acting normal, Michael. Only the diesel side will keep up adequately. Before hitting the shower, be sure to flip on the diesel side. The electric side is okay for low demands, and is useful to help defer using more diesel than you have to when you've already paid for electric-included RV sites anyway.
You should also notice, especially on cooler days, that your furnace outlets shut down after a few seconds of hot water use, because hot water has priority over space heating, and the system makes sure with the diesel side that hot water is as plentiful as possible.
-Joel
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Is switching to the diesel side more complicated than turning the burner is switch on?
MJ
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The two will operate concurrently. You can have on neither, one or the other, or both. They have different thermostat settings so that they will not fight each other. If both are turned to their ON setting, then the thermostat settings force them to cooperate with each other to heat water.
Our coach has a breaker in the main 110v breaker panel located in the bedroom to turn ON/OFF the hydronic (electric water) heater in the Aquahot. The Hydronic heater will only operate while plugged into shore power or with the generator running. In our coach the Diesel Burner switch for the Aquahot is located on the wall facing forward above the kitchen sink's countertop and over the end of the couch. Next to it curbside is located the Engine Preheat switch which circulates heated coolant to the engine for those cold morning startups. They both have green lights to show they are in the ON position. Next to the Diesel Burner switch street side is another Aladdin joystick and the living room thermostat control box. The Diesel Burner operates through the inverter, so it will operate from shore power, generator power and battery/inverter power. It will also operate while traveling down the highway on engine alternator power, but that should never be necessary because the engine will heat water in the Aquahot through the same coolant hoses that deliver heat to the dash heater and engine preheat.
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I have the diesel burner switch on all the time and still not enough hot water to take a full shower. Is there something down in the Aqua Hot I need to check or change?
MJ
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The first thing I would check is to make sure the diesel burner is actually running. Turn off the electric water heater, turn on the diesel burner and now turn on the hot water at the outside water bay. In a few minutes the diesel burner should start up and you will have hot exhaust coming out its exhaust pipe located just aft or under the outside water bay door.
If you don't get hot exhaust, then the diesel burner is not burning.
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The two will operate concurrently. You can have on neither, one or the other, or both. They have different thermostat settings so that they will not fight each other. If both are turned to their ON setting, then the thermostat settings force them to cooperate with each other to heat water.
David,
On the "cheaper" and smaller HydroHots of the vintage in the '04 we had, there is only one thermostat. It triggers both or either the electric or diesel. They were not triggered separately. Larger, more expensive AquaHots allowed you to leave both switches on and the diesel would "back up" the electric. With the HydroHot, you pick one or both and they come on simultaneously.
It may be different on any of the several other HydroHots.
Bill
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With Mr. Hannan having a 2003 Marquis Ruby 40' I am assuming his coach is equipped with a system similar or identical to mine... an Aquahot AHE-100-02S. Since he did not specify his equipment I can only assume it's similar to mine given our coaches' similar year and model.
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Michael, every once in a while ours quits for whatever reason. Simply "rebooting" it by turning the diesel switch off for a minute and back on seems to reset everything. If you've left yours on for a long time, you might try that. But usually when ours needs a reset, the electric side is out also, so it may not fix whatever is wrong with yours.
As David suggests, even if for some reason you haven't been hearing the burner fire up and run, you can certainly sense it at its exhaust outside if it's operating properly. If not, then whatever was serviced on it last was not done as a particularly complete job, something's gone awry since, or perhaps your mixing valve isn't up to snuff, letting relatively too much cold through; but if it was the valve I'd expect even the electric side alone to be too cold even at the start of a shower.
I assume because you are plugged into park power and your inverter is fine, that your recent battery issues are not involved with the ignition side; still, if you haven't already, I would check the AquaHot's panel in its bay to make sure the LED lamps are all green, and that a low-voltage status from your battery switchout hasn't affected the ignition circuit. "Rebooting" the system with the diesel switch as I described should rectify any faults there, but it won't likely fix a more serious problem with the burner itself or other causative agents.
-Joel
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With Mr. Hannan having a 2003 Marquis Ruby 40' I am assuming his coach is equipped with a system similar or identical to mine... an Aquahot AHE-100-02S. Since he did not specify his equipment I can only assume it's similar to mine given our coaches' similar year and model.
Yes this is the model I have. I'm reading the manual now. Mr. Hannan? Have I upset you in some way David?
MJ
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The first thing I would check is to make sure the diesel burner is actually running. Turn off the electric water heater, turn on the diesel burner and now turn on the hot water at the outside water bay. In a few minutes the diesel burner should start up and you will have hot exhaust coming out its exhaust pipe located just aft or under the outside water bay door.
If you don't get hot exhaust, then the diesel burner is not burning.
Ok I did that. The diesel didn't kick in by itself. I had to go and turn the Diesel Burner switch off then on. The exhaust doesn't feel hot but there is hot water coming out of the faucet again with the electric side shut off at the breaker panel. But it's not stay hot and the diesel shuts off after a couple of minutes.
MJ
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With Mr. Hannan having a 2003 Marquis Ruby 40' I am assuming his coach is equipped with a system similar or identical to mine... an Aquahot AHE-100-02S. Since he did not specify his equipment I can only assume it's similar to mine given our coaches' similar year and model.
My mistake David. The topic started with a Monterey. I didn't read well enough to pick up that Mr. Hannan has a Marquis. Your's and his should work differently in a couple ways.
One difference is that you should get a better shower on electric. The coolant tank is big enough to store more heat energy so the shower won't cool it off as fast.
Some Marquis also had two electric heating elements that could make a lot of difference in cooler weather. The single HydroHot electric element could only keep the interior warm if outside air was above about 50 degrees.
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The first thing I would check is to make sure the diesel burner is actually running. Turn off the electric water heater, turn on the diesel burner and now turn on the hot water at the outside water bay. In a few minutes the diesel burner should start up and you will have hot exhaust coming out its exhaust pipe located just aft or under the outside water bay door.
If you don't get hot exhaust, then the diesel burner is not burning.
Ok I did that. The diesel didn't kick in by itself. I had to go and turn the Diesel Burner switch off then on. The exhaust doesn't feel hot but there is hot water coming out of the faucet again with the electric side shut off at the breaker panel. But it's not stay hot and the diesel shuts off after a couple of minutes.
MJ
Michael,
The noise you heard when you flipped the diesel switch was it running through the starting cycle. But, from what you say, the burner is not lighting. If you don't see some initial smoke, feel a hot exhaust and smell diesel fumes, it didn't light.
There is a series of trouble shooting steps and several reasons the diesel might not light. First is to be sure there is more than 1/4 tank of fuel. In my files I have a good trouble shooting guide written by Roger Berke that I can email you if it would help.
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Well, Mr. Hannan, my father taught me to mind my manners and respect my elders. lol I will be 67 on May 21, but have owned the Marquis almost four years... but (again) have been retired for just over 14 years. My experience has been that most of the Beaver owners I have met are older than me... thus, my elders... like Mr. Sprague... although Mrs. Sprague is much younger than Mr. Sprague... and much, much cuter, I would add.
Anyway, it sounds like your diesel burner is not igniting if the Aquahot exhaust pipe is not smelling of diesel smoke and not hot.. That could be caused by a number of issues, or a combination of a number of issues. Be that as it may be, I was in management most of my career. I will let the more experienced Beaver troubleshooters carry the ball from here.
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The first thing I would check is to make sure the diesel burner is actually running. Turn off the electric water heater, turn on the diesel burner and now turn on the hot water at the outside water bay. In a few minutes the diesel burner should start up and you will have hot exhaust coming out its exhaust pipe located just aft or under the outside water bay door.
If you don't get hot exhaust, then the diesel burner is not burning.
Ok I did that. The diesel didn't kick in by itself. I had to go and turn the Diesel Burner switch off then on. The exhaust doesn't feel hot but there is hot water coming out of the faucet again with the electric side shut off at the breaker panel. But it's not stay hot and the diesel shuts off after a couple of minutes.
MJ
Michael,
The noise you heard when you flipped the diesel switch was it running through the starting cycle. But, from what you say, the burner is not lighting. If you don't see some initial smoke, feel a hot exhaust and smell diesel fumes, it didn't light.
There is a series of trouble shooting steps and several reasons the diesel might not light. First is to be sure there is more than 1/4 tank of fuel. In my files I have a good trouble shooting guide written by Roger Berke that I can email you if it would help.
I have just over 1/4 tank depending how accurate the gauge is. Yes please send the trouble shooting guide.
Thanks
MJ
**Michael, I deleted your e mail, per Bills suggestion. Your e mail is easily found by our members in the directory! Cheers! Carol Moffett, moderator.
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Well, Mr. Hannan, my father taught me to mind my manners and respect my elders. lol I will be 67 on May 21, but have owned the Marquis almost four years... but (again) have been retired for just over 14 years. My experience has been that most of the Beaver owners I have met are older than me... thus, my elders... like Mr. Sprague... although Mrs. Sprague is much younger than Mr. Sprague... and much, much cuter, I would add.
Anyway, it sounds like your diesel burner is not igniting if the Aquahot exhaust pipe is not smelling of diesel smoke and not hot.. That could be caused by a number of issues, or a combination of a number of issues. Be that as it may be, I was in management most of my career. I will let the more experienced Beaver troubleshooters carry the ball from here.
I'm not so eld. LOL 62 later this year. I'll check out the the trouble shooting guide from Mr Sprague and see if I can get this sorted out. Thanks.
MJ
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Michael, it isn't unheard of that the factory didn't place the genset and/or hydronic fuel pickup tubes properly in the tank. If that's the case in your instance, the hydronics fuel tube is higher than the 25% point, and your gauge is admittedly imprecise, the fix may be as simple as fueling up. Afterward, it may take a few start attempts for a dry fuel line and pump to prime and get diesel to the burner.
It's best practice to not let the fuel level drop much below 50% before looking for a diesel station anyway. I once ran dry half way up a slight Oregon Coast hwy. grade in our old gas motorhome, because the gauge led me to believe I still had a quarter tank. The resulting hassle taught me the half-full-and-fill habit. Plus, not letting the tank languish near empty helps minimize water condensation on the inner tank walls during cool nights.
Joel
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Well, Mr. Hannan, my father taught me to mind my manners and respect my elders. lol I will be 67 on May 21...... thus, my elders... like Mr. Sprague... although Mrs. Sprague is much younger than Mr. Sprague... and much, much cuter, I would add.....
I hit 70 this summer! And, I'm glad that earns your respect. I need all I can get now that we're camping in something small enough to be your "toad".
Bill
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I have just over 1/4 tank depending how accurate the gauge is. Yes please send the trouble shooting guide.
Thanks
MJ
Michael,
You might want to try to edit this to remove your email address. It is supposed to be a bad idea to post it in public forums. I could have found it in the relatively private BAC directory.
I'll send you the guide written by Roger Burke and a copy of the the Hydro Hot manual I have. I'm pretty sure you can get a manual to match your model of AquaHot at the AquaHot website.
Before you do any serious trouble shooting, put some fuel in it!
Bill
Bill
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If you need the manual for the AHE-100-02S:
http://www.aquahot.com/esource/ecom/esource/staticpages/documents/AHE-100-02S%20Service%20Manual%20Rev.%20B%209-27-2011.pdf
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I must say this is a place I need to visit every day, LOL
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up date folks..
our aqua hot model #HHE-500-07M has had mother board, motor burner, both pumps, bearing kit, and a few other $20 parts.. this was done at Beaver in Bend, I think you all call it BCS.. on 3-18-16.
All was good and plenty of hot water for my DW (wife) during the few months we had hot weather and didn't need to use the Diesel part of the Aqua Hot, Elec. was good enough.. now since we are back to the wet weather and cool nights we went to Diesel and shut off the Elec. side.. no hot water..
Bill (previous owner) left me all sort of service manuals and trouble shooting books and I have tried my best to figure stuff out.. During the 3 months I have narrowed it down to a"Low Battery Voltage Fault" I reset it two days ago and so far so good. Bill had asked if the coach batteries had been replaced and they were when we bought the coach in 2015, I might add we have a '04 monterey. I am going to leave it on 24/7 on Diesel for the next month and see if all still is good, if so then it might be my inside switch, and that reason is because when I have trouble, in the three months after BCS fixed it I would turn on from switch listen for cycle and run around and feel for hot exhaust and the smell of Diesel and repeat until I got all on for longer than 3 minutes..
Bill is right the Aqua Hot is the only thing I spend my time with fixing, I may just follow 70 degree weather and be happy with electric LOL
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Rick,
When we owned it, we left the electric on 24/7. It provided enough hot water for hand washing etc. It also kept the HydroHot up to operating temperature. When we knew we wanted hot water for a shower, dishwashing, laundry, etc. We would flip the diesel switch. Often, nothing would happen because the electric element was keeping it up to temperature. After a few minutes of hot water use, the diesel would respond and light up. First you hear it "pumping and priming" then a sort of "poof" as it actually lights. When the shower or laundry was done, we flipped the diesel switch off.
I would not leave the diesel on for a month with the electric off. It will cycle on and off frequently to keep it at operating temperature even if you are not using hot water. The cost of diesel will be significant!
There are more than a few RVers that follow the 70 degree line!
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OK, once again thanx for all the input. We have had some time to diagnose the troubles alittle more now.
First we found that having the water pump on & being hooked up to city water was causing us to run out of hot water. We did this as the city pressure was much lower than the pump. Think the water was bypassing somehow. Problem solved by using either one or the other.
While using just Diesel for heat, due to 30amp only at site, several adjustments to the shower were needed to keep a steady temperature, not a big issue, but indicates something might not be right.
Moved to a 50amp site & began using electric & diesel, no change in water conditions, but noticed that the diesel would fire on & off during the course of the day, even when not using water or heat. I understood that the diesel should fire only if electric couldn't keep up. The burner motor would also cycle on & off several times & not fire before shutting off. This was intermittent & not require any sort of reset.
Switched diesel off left electric on, & am using Heat Pumps for heat, All is good. Plenty of hot water with no adjustments necessary & heat for coach.
The concern is that something is not right with the HydroHot system. Any ideas?
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" we found that having the water pump on & being hooked up to city water was causing us to run out of hot water. We did this as the city pressure was much lower than the pump. Think the water was bypassing somehow. Problem solved by using either one or the other."
That makes no sense. When you open a valve, water will flow from the source with the highest pressure. It will be from the city or the tank with pump. The pump will not "boost" city pressure. If city pressure is below the pump trigger point, the pump will come on leaving city water with the city. Running out of hot water has nothing to do with the source. One exception is that the outside shower valves are on, but the shower head button is closed. That will mix the hot and cold in an unpredictable pattern. We've all done it a few times!
"While using just Diesel for heat, .... several adjustments to the shower were needed to keep a steady temperature, not a big issue, but indicates something might not be right. "
Yes, something is not right. Diesel can produce about 50,000 BTUs of heat. That is a lot. If all is functioning correctly, you can turn on the shower, set the water temperature and it will stay steady until you run out of diesel. Electric can make about 5,000 BTUs. That is not a lot. Electric can't keep up at heating a continuous stream of hot water. Electric alone should allow you to get wet in the shower, soap up and rinse. But you should need the water off for the soaping part. If you are shampooing long hair you will probably run out of hot water before the rinse is complete.
"Moved to a 50amp site & began using electric & diesel, no change in water conditions, but noticed that the diesel would fire on & off during the course of the day, even when not using water or heat. I understood that the diesel should fire only if electric couldn't keep up. "
I don't know what model of Hydro/Aqua Hot was used on the '06 Monterey. Our '04 Monterey had the small, less deluxe version. It had one control thermostat that triggered either or both the diesel and electric simultaneously. As the "boiler fluid" cooled, the control thermostat would close and either or both the diesel burner and electric element would start producing heat. The boiler fluid will cool as its stored heat is used for hot water, heating or normal cooling off. To have it ready for making hot water, the boiler fluid must be kept up to temperature by leaving one or the other on continuously.
"The burner motor would also cycle on & off several times & not fire before shutting off. This was intermittent & not require any sort of reset."
This is not normal. If the control thermostat is triggered and the diesel switch is on it, should make noise for about 10 seconds and light. You should hear burning and see or smell exhaust. If the burner does not light the first time, regularly, there is one or more problems. Trouble shooting is complex because several things could be not working.
"Switched diesel off left electric on, & am using Heat Pumps for heat, All is good. Plenty of hot water with no adjustments necessary & heat for coach."
Using the heat pumps for heat has nothing to do with making or not making hot water. Having "plenty" of steady hot water without adjustments does not make sense. On electric only you should get steady hot water for about 5 or 10 minutes. After that, it won't keep up. If you are using diesel for heat and you have the smaller Hydro/AquaHot, the heating portion will stop after a few minutes of hot water use.
"The concern is that something is not right with the HydroHot system. Any ideas?"
There is one or more things wrong with your system. On diesel, you should get steady hot water (just like in a stick house), but for even longer. There are many pieces to the puzzle. It ranges from fuel pressure, burner tubes, flame sensors and nozzles to stir pumps and thermostats. You need more than a Hydro/AquaHot service tech. You need one that really knows trouble shooting and has the tools for it. Flames and fuel are involved! In 12 years with our Monterey I found only two that could do complex trouble shooting! I found three or four that could not, guessed, replaced parts and didn't solve the problem.
Good luck!
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Here's my 2c worth. I leave electric on always. Turn diesel on only as needed ,dishwashing and showers.The trick for showers is turn heater thermostat in bath to max before shower . That gets Hydrohot going to preheat boiler .Makes a noticeable improvement in shower. In the summer just leave the heater fans off.
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Yes, Bill, you are right, many of these issues do not make sense, but they are present. I know the pump draws from the tank, but it acts like the outside shower vales are open which has been done in the past. Like I said, not a big issue, just trying to provide enough info for a proper diagnosis. Yes I know the heat pumps do not use water, but a reversing valve in the refrigeration circuit, just knew that electric would not keep up with coach & heating. Yes you could be right that the diesel & electric fire simultaneously & that would explain that. Do not smell any combustion taking place in exhaust, seems like it is trying to shut down & getting a signal to fire at the same time. The diesel circuit appears to be firing correctly & stays on when needed, it seems more like the water circuit is not circulating thru the transfer point or mixing correctly. Is that possible?
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"I know the pump draws from the tank, but it acts like the outside shower val[v]es are open which has been done in the past. "
So, ensure the outside shower valves are "OFF".
"...a reversing valve in the refrigeration circuit, just knew that electric would not keep up with coach & heating. "
The "reversing valve" in the A/C units on the roof have absolutely nothing to do with the Hydro/AquaHot.
"Do not smell any combustion taking place in exhaust, seems like it is trying to shut down & getting a signal to fire at the same time. The diesel circuit appears to be firing correctly & stays on when needed...."
That is confusing. You can't have a need to run and shut down at the same time. It is not firing correctly if it is trying to shut down too!
"....it seems more like the water circuit is not circulating thru the transfer point or mixing correctly. Is that possible?"
Yes, there is a mixing valve that can be stuck. There is also a stir pump that breaks. I replaced one mixing valve and two stir pumps.
It is likely that nobody can give you a quick fix on this forum. You are describing too many variable component failures. You need to find a Hydro/AquaHot professional that is both trained and experienced in troubleshooting. Your descriptions suggest your system has aged and was not well maintained.
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Well it appears that I have failed to properly communicate my thoughts thru poorly worded or phrased sentencing, which would not be the first time.
Instead of re-hashing the symptoms, I would like to rephrase the original thread & ask if anyone else has had similar troubles & if so, what was done to correct it, or if not, then a recommendation on a qualified Tech perhaps in the Bend area would be appreciated. Thank you
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Ok Dennis. Let me try again.
Again it was a '04 Monterey with the HydroHot. Back then, HydroHot meant it was a junior model for an AquaHot. It was smaller, used less fluid in the tank, had on thermostatic switch, used ethylene glycol (Prestone) for boiler fluid and would heat the cabin or the water, but not both at once.
In short, we've had hot water inconsistency due to malfunctions of the mixing valve, the stir pump, control box and the burner itself.
In the beginning and the end of ownership it worked perfectly. Hot water maintained consistent temperature for as long as you wanted to shower. It was as good or better than a stick house. For a lot of the time in between it worked well too.
However......!
The first strange problem with a variety of confusion was discovering several of the screw connectors on the HydroHot board had never been tightened. That was easy to fix and made a significant improvement in overall functionality.
At about year two the water temperature would not stay steady and we went to Beaver Coach Sales. The tech, without any serious trouble shooting assumed it was the "mixing valve" in the back. The mixing valve is borrowed from stick house systems and was made by Honeywell (I think). Since hot water coming directly from the HydroHot is too hot for humans, it has to be automatically mixed with some cold water. The mix valve does not like hard water deposits and can get stuck. The "mix valve" replacement was an improvement, but did not completely fix the problem. The new mix valve came with a label on it saying the selector on it should be cycled annually and replaced to the prefered position. You may be able to make your hot water more consistent by unsticking the mixing valve.
The same tech then guessed it had to be the "stir pump". That is a small, nearly silent, circulating pump. Apparently the smaller HydroHots needed that to keep the boiler fluid consistent when you start drawing hot water. Without it the boiler fluid near the water coils cools too fast. The stir pump replacement fixed it.
At about year 4 or so, several things, including hot water consistency was not right. Previously a fitting in the back had loosened (due to not being tight in the first place!) and was spraying water so that the HydroHot ran in a steam bath for awhile. Beaver had put the Webasto control box in the bracket upside down! That allowed enough moisture into the sealed box and the tiny mechanical relays were having a hard time and early death. A new $900 box fixed it!
Somewhere around year six, we were having some minor trouble. Apparently the burner was not lighting consistently. The boiler fluid temperature would drop too far for consistent showers. No specific repair was done because a routine service seemed to have fixed it.
At about year 8, showers were good only if you let it run long enough to get the burner to fire. Over two years I had three (certified by AquaHot) techs look at it. All agreed the stir pump was working because the outlet hose was hot. The forth tech at about year 10 agreed to completely troubleshoot.
He did the following.
- He measured the concentration of antifreeze. Each time I added a little I used 50/50. But, it is the water that evaporates so the mix had become more like 70/30. It got better! Better was measured by running hot water at the outside shower and measuring it with a thermometer.
- He measured a variety of voltages and pressures, including fuel pressure. No change.
- He did a complete service of the nozzle, burner and filter including replacing a cracked burner tube. No change.
- He determined that everything was now as good as it could be.....except maybe the stir pump. It could be pumping enough to keep the outlet hose hot, but not enough to do the stirring. He put on a new, improved and heavy duty model. It worked! Showers were perfect again and remained so until Rick LaLande and his wife bought it. He wrote in an email that it broke again!
In between the shower consistency episodes, the electric element failed, plastic connections in the back split, the relay for the electric element failed, the high limit safety thermostat failed, the "old school" extra large boiler cap failed (twice), the (cheap) overflow tubing failed, the low fluid sensor died and a bearing deep inside the burner failed.
I spent a lot of "quality time" with our HydroHot!
Based only on our experience, I would suggest:
1. Make sure the burner fires every time the system calls for it. With our HydroHot both the electric and diesel worked together. I could look at the amps on the Alladin and see if the electric element was being used. If it was, and the diesel switch was on, the burner would be running too.
2. Get to the mixing valve and make sure the knob rotates. Do make sure you put it back where it was when you started. Some say it can be carefully wiggled with big pliers to break it loose if stuck.
3. Based on what for me was a high failure rate, a new stir pump may be what you need. The stir pump is a gamble because it is nearly impossible to test it for full capacity.
Good luck!
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Thank you Bill, that is the info I was looking for. Some of the issues you've experienced are what we too are having. I plan to access the mixing valve, exercise it, & will be checking all connections I can find.
The maintenance records we received at purchase, from the original owner 2 months ago, indicate maintenance was kept up with. Burner is firing properly but at the end of the cycle, the burner will cycle rapidly on & off 10-15 times before stopping, which may indicate a control problem, possibly in the board, not sure yet, but am concerned. Aladdin shows that 11 amps are being used while the electric is on. From what I've read, these systems can be frustrating at best.
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Thank you Bill, that is the info I was looking for. Some of the issues you've experienced are what we too are having. I plan to access the mixing valve, exercise it, & will be checking all connections I can find.
The maintenance records we received at purchase, from the original owner 2 months ago, indicate maintenance was kept up with. Burner is firing properly but at the end of the cycle, the burner will cycle rapidly on & off 10-15 times before stopping, which may indicate a control problem, possibly in the board, not sure yet, but am concerned. Aladdin shows that 11 amps are being used while the electric is on. From what I've read, these systems can be frustrating at best.
The mixing valve on ours could be reach over the top from the front but I could not see it nor have enough grip and leverage to exercise it. I had to crawl under and remove the back panel. I've seen other installations where there was no backside access!
The "at the end of the cycle, the burner will cycle rapidly on & off 10-15 times before stopping" is challenging. The system has two "brains". The original burner system from Webasto comes from Germany, is used primarily in large boats and has a mechanical brain or "control box". On mine, it was held in a bracket on the aft side of the burner. After mine was replaced I tore the old one apart. Doing so destroyed it. Inside was a set of precisely engineered and tiny mechanical relays. On or two of them had stopped working but they looked OK.
Finding the control box fault was difficult. The system was relatively knew and I had not learned how it worked yet. It was not shutting down correctly. It was nearly a decade ago, so remembering the exact symptoms is not possible! In desperation I appealed to the "approved" shop to let me pay a tech to sit there and do nothing but watch it for up to two hours! It was worth $200 to find the problem. I knew it was not shutting down right but did not know how or what to communicate to the tech. After about 45 minutes the tech said something like, "Ya know you're right! It won't shut down like it should until I lightly knock the control box with the handle of my screw driver. You need a new control box".
The other "brain" is electronic. It is a product of AquaHot and is made to "adapt" the marine Webasto to motorhomes that have heat pumps, air conditioners and use DuoTherm thermostats. The electronic AquaHot brain "talks to" the mechanical Webasto brain. It can be very confusing which "brain" is a problem when the system is not behaving.
11 amps is about right for the electric on the Aladdin. On ours, with both the electric and diesel switches on, you could hear the the burner go into the shutdown cycle as soon as the 11 amp draw stopped. You could run hot water, go to the Aladdin and watch for the 11 amp draw. The moment the readout added the 11 amps you could hear the diesel burner start up.
Again, good luck. The HydroHot was the most complex system in our Beaver. When it worked it was wonderful. We had a lot of outstanding cold weather trips where it worked perfectly. That said, it was a front runner for consuming maintenance dollars!
Bill
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Update
Tightened all connects I could access. Found a couple of loose wires on the terminal block coming from the Wabasto controller to the burner motor. That didn't fix the problem of cycling during post-purge. Talked with Aqua Hot & we have narrowed it down to a motor relay in the controller. They do not rebuild these "Brains" & sells them at a cost of $892. Ouch. Will keep looking for a more reasonably priced replacement. Hope the info here & from Bill Sprague helps someone else down the road.
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This may help: http://beaveramb.org/forum/index.php/topic,5367.msg40226.html#msg40226
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Thank You Dave. That too is good info. I have been able to find less costly replacements, both old & newer versions.