BAC Forum
General Boards => Technical Support => Topic started by: Joel Ashley on October 11, 2020, 12:17:34 AM
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Never had much trouble with the HydroHot, so though I read member issues here, I’m admittedly low on memory as to this one.
After repainting the chassis side of the corroded tray with POR-15 and putting new maintenance-free Interstate batteries in (the 14 year-old ones still read 12.5 volts), I decided that before humidity rose prior to today’s projected heavy rains, I also should run the HydroHot and genset. Overdue was the regular 20-30 minute exercise I try to give them while the coach is “stored” here by the house. The HH wouldn’t start up, so I tried the usual off, pause, and back on reset. Still nothing. So I checked the panel lamps in its bay and found the Low Fluid one illuminated red.
Must’ve been just long term evaporation to somewhere. The coach has been “stored” for almost 4 years. Yup, the expansion tank was below the Cold line, so I added 50/50 boiler mix to that line. But then, there is no sensor on that plastic tank like on the CAT’s, so I’m thinking this ain’t as simple as that. I figure, okay, the fluid level sensor must be in the main tank. I try removing the radiator cap, figuring to add fluid until the lamp goes out or turns green. Cap loosens but won’t come off. Hmmm.
If all else fails, read instructions. From that I get I have to find a way to pump fluid in through the drain valve! Really? I obviously can’t get fluid sucked back from the expansion tank without first heating and cooling the main tank, and of course it won’t start to begin with. So is my only option to rig a manual or electric pump and plastic tube to the drain valve? Or is there a trick to getting the radiator cap off? There appears to be no release gap it’s locking flanges can be turned to. Can I attach a tube to the drain valve, hold it up higher than the unit’s top, and funnel in fluid to raise the tank level?
The HydroHot model is HHE200-09E. While awaiting any responses here, I’ll go dredge up that specific model’s documents from the AquaHot library, because the manuals I’ve seen so far have varying or insufficient commentary troubleshooting this problem, or relate to other models.
I suppose it could be a gunked up float switch, but the low expansion tank level would seem to counter that notion. I could jumper the switch’s two circuit board wires on the controller and bypass the switch to likely power up the unit, but if the fluid is actually low in the main tank, that would be ill-advised I would think.
Joel
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Joel
Sooner or later that rad cap will have to come off.
With that said be careful not to break the filler neck loose in the tank.
If the outter cap is turning and released the problem is likely that the inner rubber seal is stuck in the filler neck
A couple of suggestions
1) you could try to spray a pendant up under the loosened outer cap to help break the rubber loose from the filler neck only problem here is it will likely contaminate the boiler fluid.
2) try heating the fill neck some with a propane torch to get the seal to let go just be careful not to overheat the neck and break
the solder joint at the tank you could keep the lower neck cool by spraying water on it while you heat the upper.
3) you could try drilling the river out of the center of the calm which would release the inner cap from the outer allowing you to get into the inner cap where you can now remove the spring and inner seal one price at a time.
4) or you could just use brut force and ignorance ( not recommend)
This may be why aquahot recommend replacement yearly not that anyone does that.
Although if it were removed once or twice a year may help avoid it sticking again.
Hope this helps and good luck
Eric
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Thanks for replying, Eric. I don’t believe the rubber seal is the problem.
As I alluded to, the cap is loose enough, but there doesn’t seem to be a gap in the standpipe’s edge for the tightening flanges under the cap’s edge to slip out of. As I recall from automotive applications, that you are more of an expert about than me, modern radiator caps are built such that they cannot blow off when loosened, and some maybe aren’t removable, at least not by us old-line farm “mechanics”.
🤔 Joel
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Joel
Most rad caps have a second detent to hold the cap from blowing off if loose Ed under pressure if you push down on the cap and continue to rotate it it should move passed the final detent and then lift straight up and off.
Eric
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Eric is spot on Joel. You have a safety detent that prevents the cap from coming off should it get loosened and it can be difficult to push the cap down enough to rotate it past those tabs. My 03 Monterey has the large cap and its getting harder for me to get both arms in there while pushing down at the same time. Persistence will pay off eventually.
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Joel,
The difficulty of pushing down on the cap and turning at the same time as we get older is obvious. Perhaps a pry bar and a 2 X 4 cut to length would give you the leverage you need. Regardless, you need to get the cap off so you can add enough boiler mix to raise the float. Hang in there, you're a smart guy and am confident you will get there! Fred
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Yeah, Fred, just not smart enough to remember you have to push down for the second detent🤪. Shows how long it’s been since I’ve checked anything beyond expansion tanks, letting service centers change fluids as schedules dictate. The angle of approach to the cap, due to the cramped quarters and being on my knees and it starting to rain, did not lend itself to my recollecting that the cap had to go down once loosened. If I’d been standing upright over it I’d probably have pressed down as second nature! I just used a penlight to examine the flanges and from my limited view couldn’t see any way for them to clear one another.
Gad, my brain seems to be aging faster than the rest of me; and that’s sad enough 🤣.
Thanks fellas... my cobwebs needed a good shaking. Just in time for All Hallows Eve.
Joel
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Joel
Did you get the system topped up and running?
Eric
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Joel - Yes, I agree with almost all you said... especially about our aging phenomena. When I needed to add antifreeze to our Aquahot several years ago, I knew I had to push down harder and twist the cap more firmly to get past that second detent. The problem is that position on our knees and then having to reach out about two feet makes it difficult to gauge how much pressure we are applying. Thus, I broke the collar off and it came into my hand with the radiator cap! After several years and a few annuals of the Aquahot, I can confirm that JB Weld is pretty good stuff. lol
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Joel,
You didn't say whether you got it off. Hope you did!
I had the same problem as you, except when I did the second push down, and it started to turn, the cap ran in to the clamp that holds the hose tight. The one that goes from the neck to the expansion tank.
At the same time, the screw that tightens the clamp was facing away so it was hard to get to it. I eventually got the screw loose, slid the clamp out of the way, and was able to get the cap off. Big time hassle. I re-worked the whole thing when I put the cap back on.
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It’s been raining and I haven’t been at the task again since. But I did manage another bohunk move related to it before trying to get the cap off.
First thing I did when seeing the low expansion tank level was add fluid, right? Knee jerk reaction for any of us, I reckon. Boiler Fluid only; check. Dilute tp 50/50; check. Pour the mix into tank; check...
Realize suddenly you should use only distilled/deionized water; ... (cough)... check.
So now when the rains cease I have to clamp off the bottom tank-to-HH hose, get down practically on my belly, finagle one or more hands with pliers into the impossibly tight space under the tank - with rags and engineered catch basin, and remove the hose to drain the tank of mineral contaminated boiler blend. That one hose uses a small spring clamp, not a stainless screw one which would’ve been easier to loosen. And of course, the prongs on it are turned toward the sidewall!
Hey, at least thanks to you guys I can forget the previously anticipated notion of having to pump fluid into the main tank via its drain valve! Forgetting stuff seems so much easier these days. ;D
I’ll get back to you when it’s dry enough to work out there.
...If I remember.
Joel
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Joel
Why not just syphon off the top half of the recovery tank out and add the deionized water to the remainder.
Eric
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Yeah, did that already. Unfortunately for me I’m a perfectionist, and will go to some lengths to achieve little. If I can get the tube off and get that last bit of tap-water out that the siphon hose couldn’t get, the many ancestors that taught me detail focus will smile down from above.
Of course a certain amount of cursing in the process of getting that clamp off may have a negative effect on such angelic oversight, in which case I’ll likely throw in the towel. No wait, I already put towels in there, didn’t I?
Joel
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Joel,
WADR I'm reading this thread and wondering what your goal is. In all honesty it appears you are on a path to put up with a tank cap that you can't remove so you will continue to come up with painful and unnecessary work arounds. Get the cap off! I had a similar issue on my 01 (large cap) and ended up using an extender bar and wedge as a leverage fulcrum to apply downward pressure to the cap and a very large channel lock pliers to turn the cap. It came off with no damage to the tank neck but the cap clearly needed replacement. If I misread or misinterpreted the post, I apologize.
BTW, strongly suggest you use a refractometer to validate your mixture BEFORE adding any fluid.
Steve
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Due to heavy rain I haven’t gone back out to try pressing down the cap while turning. I’m sure it will come off when I do. I’ll check the fluid quality/density as suggested, as any evaporative fluid loss that’s the initial startup problem should be water content. I may need to add just pure distilled water.
Joel
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Joel, many times when the fluid drops below the float switch be prepared to see the float stuck . After replinishing the tank you may have to nudge the float lightly if the low fluid light remains on. Float will usually return to normal operation in most cases.
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Yeah George, today during a rain break I went out and the cap came right off when I pressed down for the second detent. The fluid was right up to the top of the filler neck, too. So I took the panel off the unit’s front to see the layout relative to reference documents and articles I’ve accumulated over years. If necessary I can drain the tank low enough to remove the level “sensor” switch and check or replace it. Rains began again.
When I can I’ll see if I can insert a clean rod or stiff wire of some sort through the filler neck and gently dislodge the switch‘s float. Is that how you did yours, or did you remove the entire float switch? I might also jumper #15 & #16 on the circuit board to verify the switch is indeed the problem.
One thing I’m not familiar with is the drain valve setup... it’s not like images I have of it. It’s white PVC, not brass, conveniently extends out past some wiring looms, etc., and terminates with an opening that has a plastic sleeve inside it that’s loose and turns easy, but doesn’t seem to come out. Deeper inside, before the plastic (ball?) valve itself, I see an “O” ring. It’s like it’s meant to have a 1/2” I.D. hose pressed into it for draining purposes. Am I on the right track with that interpretation?
I will need to consider that I don’t need this happening on a trip, and may replace the old float switch regardless whether I get the float working again. I guess there is a newer electronic version that can report the fluid level... to an app or what I’m not sure. It’s probably spendy.
Joel
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Joel I believe the float switch is a magnetic contact switch when the fluid raises the float to a horizontal position there is a magnet on the back side of the float arm which when brought into proximity with the switch will cause the switch contacts to close making the circuit .
In your case as the fluid has not gone down below the float you would assume the float should not have dropped down / out and that the problem would there fore be the switch contacts .
How ever that assumes the float hasn't developed a crack and sunk.
Your on the right track play with the switch and see what you find you could Disconnect it and checking with an ohm meter while you play with the float to see if the switch part actually works
On a side note the older Aquahot like my 412 did not have a float switch and as a result when I got mine the burner pot in the tank had been run low on coolant and had developed a crack ( when the system was running the crack would open up and allow antifreeze into the burner chamber cause large clouds of white smoke like a bad head gasket in a car engine)
I ended up using a plasma cutter to remove the chamber from the tank and canalized another DBW 2020 webasto truck coolant heater to get the chamber I needed to weld back into the tank.
Interestingly when taken apart you can see where the Aquahot people had done exactly the same thing cutting the outter can off the DBW 2020 to use the burner chamber in there tank arrangement.
Anyway your on the right track
Good luck
Eric
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Joel,
I would check the float switch at terminal 15 and 16 as this is the easiest way to stay on task and evaluate that. Most likely if the unit has set dormant for 4 years, the float switch is bad. You will have to drain the unit below the access port for the switch removal. I use an old fresh water pump to back fill the unit thru the drain to burp any anti-freeze up to the fill neck. Hope this helps, Fred
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Joel, I used a long screwdriver to gently nudge the float. Since the tank was full when you removed the cap it appears that your float has become a sinker, not a float. I have changed my float numerous times and I have to siphon the fluid into a clean pail. My unit does not have a drain valve. As others have said do test the switch. Jumping can be a short term fix but removes your protection in case of a leak.
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So, the solution refracted to 38% (protected to 0 degrees F). I may add pure antifreeze to the expansion tank's Cold mark (~2-3 cups) just to compensate a bit more in the direction of 50% when it ever got drawn into the main tank upon cool down.
So Fred, have you seen a drain valve terminus like in my photo? Will a hose just press in and pull out? I don't have a spare pump, but do have a hand one. It's been used for water and for oil transfers, though, and I'd rather not risk contaminating this job. If I held the drain hose above the unit and funneled fluid in that way, would that do? Or if I just put fluid in via the cap, wouldn't running/cycling the unit, as per some instructions I've seen, purge air from the lines?
Joel
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Hi Joel,
I am pretty sure a piece of 1/2" Pex will push into that opening then a 1/4 turn on that valve. Give it a try. I have used that cheapo fluid transfer pump from Harbor Freight to top fill coolant tanks but not for back-filling against the existing head pressure of the contained coolant. As I recall, about 1 gallon will get you below the access port for the float. If that is all you remove, just just pour it back in after you change the float switch. Cycle all zones with the t-stat and do 2 complete cool downs and top it off. Fill the recovery tank with pure pink Boiler coolant and take that sweet heart for a ride. Fred
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Okay, will do, Fred. I just finished draining what I think is enough out. A 5/8 OD hose fit just by pressing it in... no leaks. The piece I had was only a foot long, but I sent it down under the rig by way of the burner fresh air duct that's flexible thin rubber and that easily moved to make room.
Yes, when I jumpered the circuit board connectors, the thing fired up. I tried dislodging the float, but it's hard to feel around what's happening in there. Afterwards, it still wouldn't work, so now I'm having an issue getting the float's wires tucked into a 7/8" deep socket enough to get the socket over the switch. I'm going to go get a 7/8" deep socket for my half inch socket wrench, to see if the wires will fit. I could cut them, but I'd still have to have a socket for the new switch's wires anyway.
Stay tuned. The numbers on the switches tags don't match the suggested switches in my literature, so will have to check with AquaHot I guess.
Joel
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Joel, Just wrap the wires around a phillips screw driver and remove and tuck inside a deep socket and out she comes. Glad to here you are making headway. Fred
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Well, the new deeper 7/8" socket takes more wire in, but I still can't get it over the switch. Are we sure they didn't use a 15/16"-headed switch on some units? Maybe that's the real problem.
I hate to ruin a new socket, but if the switch is indeed 7/8” then maybe I’ll try using a metal blade to cut a notch in the side of the socket, kinda like the hole in a whistle, to route the wires through. That would be less traumatic on the new switch’s wires too.
Now it's dark out, I promised Lee a 2 hour drive to visit her 92 year old brother tomorrow, and I don't have a replacement switch in hand yet. That’s more important... she hasn’t seen him for a year, and we lost my own brother in May. So I reckon this oft-interrupted job will be on hold until Friday or when I get a switch.
Joel
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Speaking of radiator caps, when I tried to remove the cap off my 2002 Beaver Marquis it fell apart into many pieces. Where can I get another cap>. AutoZone is no help. This cap has two seals so it can suck fluid from the overflow tank. The AquaHot is model number AHE-100-02S. Serisal number 01-1219.
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The first link tells me the p/n plx-102-229 cap will fit your Aquahot (same unit I have, BTW).
https://heatmyrv.com/product/radiator-cap-13-psi-aqua-hot-rv-hydronic-heating-plx-102-229/
The cap found above at $18 I thought was a bit too much, so I dug deeper. Then I found this link to a cheaper supplier on EBAY. More searching may find a yet cheaper replacement cap.
https://www.ebay.com.sg/itm/Aqua-Hot-Hydro-Hot-13lb-Radiator-Cap-PLX-102-229-10229/174343697874?hash=item2897b1b5d2:g:4FgAAOSwrbVfB1EI
Hope this helps. BTW, several years ago I purchased a new radiator cap at an Autozone or O'Reilly's. It's been on the unit since then and it seems to work. I don't remember the p/n of the cap I purchased.
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I think that’s the same cap as on mine, PLX-102-229, David. My recent looks online imply there’s basically two caps made for Aqua/HydroHots, and one has a “D” ring or “ bail” on top: PLX-403-000. That one is pretty obvious, making it easy to tell which cap any of us has.
Joel
Addendum:
Now for our daily dufus handyman update. Having struggled for hours trying to get a 7/8” socket over the float switch, even an Autozone trip for a 1/2” deep socket to better accommodate its two wires, today I almost cut a notch in the side of that socket to pull the wires clear.
But before that, I cleared away crushed insulation foam from around the switch base. Nope, that wasn’t it. Feeling in there with my fingers, I could swear the socket was too small. But, no, the website and other documents I have all said the older units used 5/8” and mine should be 7/8”. I tried Fred’s ‘wrap wires around screwdriver’ trick. Nope after countless rewrap attempts, jamming the wires deep into the large 7/8” half-inch drive socket.
Frustrated by both that and the position this old body had to take for the job, I finally swore the da#*@! bolthead just had to be bigger than 7/8”. So I dug out a 15/16” socket, but just strung the wires through it since I don’t have a deep one in that size, and wasn’t connecting the wrench. Sure enough, even free of clogging wires, it wouldn’t go over the bolthead! Okayyyy....
Out comes the 1” socket. Bingo! Slid right over the bolthead and is snug.
Lesson: when they say the switch is 7/8” they mean the threads, Dufus. NOT the wrench size.
So now, off to the Ace or Autozone for a half inch drive, 1” deep socket. And hopefully wires will stuff in enough for the socket to slide over the bolthead. The old one, no biggie, but I don’t want to risk damage to the wires on a new $150 switch. If necessary, I can still cut a gap in the socket side.
-Dufus
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Joel, I guess I have changed my switch 8 or 10 times over the years and I figured it out long ago. I drilled a hole in the socket for the wires to pass through. Wasn’t easy, went through 3 or 4 drill bits but it was worth the effort.
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Joel
The best solution is to acquire a special purpose deep socket designed to remove and install oxygen sensors. The socket has a slot cut into the side to allow for the wires to protrude while in use.
Richard
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My search into your suggestion indicated no one inch oxygen sensor sockets, Richard, just 7/8”.
I think I can get a 1” half-inch deep socket to take in all the wire and still get over the switch’s bolt head. Hope to get one today during errands. No rush, now anyway... the best-price replacement switch won’t arrive for 10 days. Spendy bugger. George, 8-10 replacements would be a tidy sum!
Joel
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Got the switch out. Once I nursed the socket over it, the doggone thing was loose! I probably could've turned it out with my fingers to start with.
Looks like the float broke off! Don't know how that could happen. The unit isn't brass either. It's all plastic, and says "Advanced Control Tech" on the remaining float stem/mount. I tried looking down the fill neck, but don't see any part floating. But then it's a broader tank than I can see from that limited position. Now I'm concerned that float could block a pump port or something. A person would have to drain the tank (assuming the float didn't plug off the drain) and use one of those flex remote cameras to see if the float could be coaxed out somehow. Aarrggghhh.
The inside of the filler neck looks pretty ratty too; grunge and particles all over it. Hard to see in the photo, but there's a greenish scum coating the device I removed. Note the crack in the stem. The gallon of fluid I drained off wasn't exactly pristine clear pink, either.
The new part won't be here for 10 days, yet.
Joel
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Joel
With the switch out you have a pretty good sized hole to look into assuming the float still floats you should be able to see it with a light.
To get it out you could try a coat hanger with a hook fashioned on the end.
Or drain the tank and run water into the tank until it spills out the switch hole and see if it won't float over to the hole use long needle nose pliers or the coat hanger to extract it .
Good luck
Eric
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Update for those interested:
I ordered the switch Oct. 17th from getrvparts via eBay as they were the best price, and there were hardly any other sources anyway. It was to arrive Oct. 29th.
10 days later on Oct. 27th they emailed to say they wouldn’t even have it in stock until later that week, and gave me the choice to get a refund or let the order ride. I didn’t cancel it. A week or so later I emailed them asking if they’d shipped it. No reply.
Yesterday I got notice from eBay that they refunded my money. Gahhhhh!
Meanwhile the weather here has become cold and rainy, and I didn’t get the unit fixed beforehand. So today I ordered the part from John Carillo and there was no estimate of delivery. I can only hope it’s before Thanksgiving and we get a dry spell (yeah, right, it’s Nov. in Portland...). I’m not smiley working bundled up head to toe, with cold fingers, and on my knees on a wet surface.
One bright note is that Carillo’s price was now less than eBay’s vendor’s, I think because he had a free shipping option. Yeah, it may take longer than 2 days or something, but now with the weather crashed that’s not particularly important.
Joel
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Joel
Hang in there the parts will come.
I here ya on the cold and wet on your knees thing I've spent many a day working on heavy equipment in the snow up here in Canada and I'll let you in on a little secret when working on the ground on your knees or back for that matter one of the your best friends is a piece of styrofoam SM or any other hard construction grade foam insulation board .
It's tough enough that you can kneel on it and it won't hurt your knees and it will keep you off the ground and dry, comfy and warm.
Eric
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Yeah Eric, I have a lightly padded 3’X4’ fold up neoprene thing for that, plus an 8”X15”X1” garden kneeling pad I can use. But the wife reminded my dim brain that I could always extend the awning a few feet (before it hits the house) to help with any rain. I haven’t used that (the awning that is 🤪) since 2012 when it opened on Canada 1 in the Rockies; I forget its there - even tho BCS fixed it, I’m gun shy towards it.
Joel
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Yeah Joel I read about your awning adventure.
I know what you mean my wife loves to point out the obvious too of course she would just tell me I'm retired now and can wait for the rain to stop .but what fun is that lol.
You'd be surprised how warm the styrofoam is when you kneel or lay on it ,it's almost too comfortable when you get down under something you don't want to get back out or maybe that's just me.
Eric
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Got a break in the weather that coincided with an hour of “spare” time, if there is such a thing. As previously noted, the original float switch was all plastic and the float part broke off at its pivot. Heat My RV (John Carillo) said that was a common failure, and the newer versions are brass. So for those with hydronics of the mid-2000’s era that have never had new float switches, beware.
I tried viewing the lost float in the tank with poor hope of fishing it out, but AquaHot deemed it inconsequential if left there, so the notion was abandoned. Of course I tried at first using the large 1” deep socket to install the new switch, because it “easily” held the wires tucked inside it. It slipped on the bolthead. Aha. Recall I had to go buy a larger and deeper socket (twice) to get the old one out after determining it was not the 7/8” touted in the service instructions. Now weeks later, I totally forgot the new switch had a smaller head! The threaded shaft is the same, but not the bolthead. My spare and dry hour unfortunately occurred near sunset and my flashlight was being cantankerous, so I reckon I was hurrying too fast for my old memory capacity to keep up.
New switch was installed and properly aligned so the float was right side up. I stuffed wires in and inserted the switch head in the 7/8” deep socket. Fred’s suggestion to wrap the wires around a screwdriver so they’d coil up easier in the socket was a helpful idea; I used a pencil. Being that the thing is buried an inch deep into a hole through insulation surrounding the tank, I couldn’t see what side of the bolthead was up, and once the wires were stuffed into the socket I didn’t want to pull the socket off to check. So before starting, I put a black hash mark on the socket so I knew when the switch was screwed in with the float properly positioned in the tank.
I mention this otherwise mundane stuff (to experienced mechanics) for anyone else that might benefit if ever replacing their switch, and running into similar roadblocks along the way. And to that end, I went to replace the burner control box on the side of the burner... roadblock. It slid off easy enough, but Guys, am I correct to insert a flat screwdriver blade along the inside of the bracket to depress the tab? I just wanted to close the unit up to finish later, as dinner called, and thought I’d simply slide the box into place. Not. I tried the small screwdriver I had handy, but struggled to get the spring-tab out of the way so the brackets would align.
When I get around to it again, is there some trick to getting the box started back onto the side of the burner? The edge of the tab catches in a shallow cut in the burner, and has to be depressed to clear it; but its spring steel is darned resistant to that. Maybe when I’m not rushed and have a bigger screwdriver...
Joel
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Update:
No one replied about the burner control box issue, so having gotten past the Holiday chaos and motored to Camping World for fresh boiler antifreeze, yesterday I finally cleaned up the unfinished HydroHot issue. The gallon of old antifreeze I’d drained to get the float port clear of fluid looked brownish and unpristine. I didn’t drain the entire tank, but just added back a gallon of fresh, clean and clear fluid, diluted down to about 55% water per my test. The old fluid was a tad strong due to water “evaporation”, and it’s not recommended to go over 50% propylene glycol or its too viscous for the pump systems. Right to the top lip touching the cap, then 45/55 fluid/water in the expansion tank to just above the cold mark.
The control box took a deftly placed, properly sized screwdriver blade to get the confounded prong out of the way, but it finally slid by the notch and into place. Clumsy to do on a dark day and poor light. Couldn’t get a good flashlight position to see the prong and slide edges.
She fired right up and ran just fine. So I reckon that task is finally completed. Still got house bats to change out. They’re almost 15 yrs. old, but still charge to 13.4v. They just boil down relatively quick and don’t hold long after unplugging. U.S. Battery or Fullriver AGM’s will likely be my choice.
Joel