HydroHot not reliable for freeze protection

[Bill Sprague]

My habit for 8 years has been to rely on the electric mode of the HydroHot for freeze protection.  It seems simple enough to leave it plugged in, set the thermostats to 45 or 50 and turn on the electric portion of the furnace.  

I check on the motorhome once or twice a week when we are staying in our condo.  Normally I don't open the HydroHot bay.  For some reason I did this time and it was stone cold.  I checked the switches and turned the temps to 65.  Nothing.  Zero amps on the Aladdin.  I switched on the diesel and it worked fine.  

18 months ago the element failed, so I suspected that again even though it is supposed to be a rare failure.   I got out the screwdriver, multimeter and HydroHot shop manual.  I expected to find 120v at the element terminals.  I was wrong.  I had 120 only as far as the high temp thermostat, which is a tiny thing with two wires and a reset button.  The reset button was falling out due to old age!

My conclusion is that the HydroHot is not reliable enough to protect against freezing.   In the Western Washington area it rarely gets below 25 F so we don't need much.  But, it does have to work reliably.

There are too many failure points in the electric system.  The element, the high temp thermostat, the 12v relay and the control board itself can each be a problem.  I've had two of them fail.  If one of those failures happened on a night below freezing I would be buying a new HydroHot!  

I am no longer going to rely on the HydroHot for winter freeze protection.  

[Edward Buker]

Bill,

My thinking is the same. Just too high a risk regarding an $8000 expense if the unit fails. There are too many components involved with each having its own marginal failure rates. Together it all adds up. If you are not winterized there are other freeze issues that would add to the expense.

I posted this back awhile ago and still think for the limited expense it would be a viable option. It would get you to the coach soon enough to take some action with alternative heat sources. Having this type of system would certainly provide "piece of mind".

Here is one option that can cell phone you, there is another choice if a wireless network is available.

http://www.temperaturealert.co.....2qo6wCFRBR7AodDVbBCg

Later Ed

[JimDyer]

Ed,

same problem as when you first posted the link.............somrthing is cutting the url off before the m in com

[Edward Buker]

Sorry...try this..

http://www.temperaturealert.com/Temperature-Alarm.aspx?Click=4152&c1=GAW_SE_NW&source=GAW&kw=temperature_alert_exm&cr5=3721061810&gclid=COfutpWewawCFYuc7Qod21PKsQ

Later Ed

[Joel Ashley]

I fully used water system antifreeze this last winter for the first time in 27 years, mostly because my coaches have always been stored at home where I can monitor them during freezes, but the monitoring got too bothersome during extended icy weather.  Like Seattle, 98% of the year is mild here, but Portland has had several snaps in recent years, with temps well below 20 degrees for up to a couple of days;  even if one night was below 30 for several hours, that could be the $8000 night.

If the coach is at home or nearby and easy to watch several times a day in cold snaps, fine.  But if not, be aware that sh** happens, and either the electric or diesel sides of the hydronics can fail for numerous reasons, as Ed says.  The risk is an expensive one to sluff aside.  On our old rig, the propane furnace had no freeze risk, and the water heater was drained.  Neither was in any case as expensive a loss as today's freeze-susceptible hydronics systems.

Joel

[Bruce Benson]

Several observations:

It would seem that leaving the electric plugged in would be the more expensive option relative to winterizing the system, assuming that the coach will be parked for a month or more.

The burner should not come on if the electric is working properly and there us no heavy usage of heat, thus leaving the burner selected to "on" would give an additional backup.  Yes, the burner could certainly fail as well.

A light bulb would protect the Aquahot but what about the rest of the coach?

A temp sensor with an alarm could be made to operate a bell, light or even the air horns.  If mounted in the Aquahot bay, the temp could be set rather high, thus warning when the failure occurred, not necessarily when the freezing is happening.

A few hour dip to freezing would probably not cause a problem.  Several days of near freezing followed by a freeze will cause a problem.

You would have to hear or see any type of alarm, thus there is still room for a failure.  Unless you are 100% housebound, winterizing seems the only way to be sure that you are safe.

[Bill Sprague]

[quote author=]Several observations:

(1) It would seem that leaving the electric plugged in would be the more expensive option relative to winterizing the system, assuming that the coach will be parked for a month or more.

(2) The burner should not come on if the electric is working properly and there us no heavy usage of heat, thus leaving the burner selected to "on" would give an additional backup.  Yes, the burner could certainly fail as well.

(3) A light bulb would protect the Aquahot but what about the rest of the coach?

(4) A temp sensor with an alarm could be made to operate a bell, light or even the air horns.  If mounted in the Aquahot bay, the temp could be set rather high, thus warning when the failure occurred, not necessarily when the freezing is happening.

(5) A few hour dip to freezing would probably not cause a problem.  Several days of near freezing followed by a freeze will cause a problem.

(6) You would have to hear or see any type of alarm, thus there is still room for a failure.  Unless you are 100% housebound, winterizing seems the only way to be sure that you are safe.[/quote]

1.  Yes, if you are putting it away for a couple months.  We like to use ours randomly.  It takes almost 5 gallons of RV antifreeze if I do the everything including the washer/dryer.  

2.  On some cheaper HydroHots (like ours) the diesel burner and electric element cycle of a single control.  If there is need for heat and both switches are on, the electric and diesel work together.  

3.  There are "in-line" thermostats sold in most hardware stores to go with the heat tape used on plumbing.  They can be used for any kind of heater (or light bulb), come on at about 35 and off at about 45 degrees.  It is easy to set one up inside and in the storage bay.  I would need to run a wire or extension cord to the waste tank bay and the HydroHot bay.  I have some 200 watt "personal heaters" that might work.

4.  One could use the same in-line thermostat and alarm for that.

5.  If it were parked next to the condo, it would be easy to check.  It is 10 minutes away where I could ignore it for a few days.  If I'm on a trip, nobody checks it.  The list of things that break in a freeze is long.  The HydroHot alone would cost about $7,000 to fix.  PEX plumbing is usually OK, except for the joints.  The washer/dryer would break and I think the ice maker would have issues.  Any water filters would crack.

6.  I agree.  Starting this year, I'm shopping for anti-freeze each fall that my DW doesn't take me south.

[Joel Ashley]

Re. the washer/dryer, I don't pump a lot of antifreeze through the long lines all the way to the back of the coach for that.  The Splendide manual indicates that only a small amount needs to be put in the drum and cycled to protect the pump, etc. - see the manual for specifics, or check Splendide/Westland's website for a pdf of your model's manual   http://www.splendide.com/

Joel

[Bill Sprague]

Re. the washer/dryer, I don't pump a lot of antifreeze through the long lines all the way to the back of the coach for that.  The Splendide manual indicates that only a small amount needs to be put in the drum and cycled to protect the pump, etc. - see the manual for specifics, contact Splendide/Westland here in Clackamas, or ask and I'll gladly post the instructions word for word.


Joel

I have both the original instructions that came with it and the "new improved" version that takes more fluid.

Thanks.

Bill

[Edward Buker]

I had a cold morning this week and decided to have the Aqua Hot electric element on overnight just in case. I went out in the morning to turn the breaker off and I usually turn on the coach monitor panel to make sure it is still pulling current for the next use. I was surprised to see 0 Amps. Lucky indeed that the outside temp only got down to 30 degrees and all was still O.K. with the Aqua Hot water coil.

I expected a bad high temp cut off sensor or a bad heating element. I had few minutes to diagnose this problem and it would appear that the sensors and heating element are fine. It looks like the neautral white wire is open somewhere. I have a 2000 Marquis schematic and it shows no outlets or J boxes between the breaker panel and a Hydro Hot on the schematic. I'll get back to this tomorrow. I'm hoping for something simple like a wire nut fell off at the Aqua Hot wiring box. We will see. If anyone has had a similar problem and has some insight let me know. These units are not all that trustworthy....

Later Ed

[Marty and Suzie Schenck]

Ed, Did you check the Aqua-Hot to see if it was hot? My Hydro-Hot cycles on and off. The electric element brings the coolant up to temp and then cycles off until coolant temp drops and then cycles back on. The electric element does not stay on continuiously, therefore no amp draw all the time. Just a thought.
Marty

[Gerald Farris]

Ed,
You said that you were using a 2000 Marquis schematic. Don't forget that the 2000 Marquis did not have an AquaHot unit. Instead they used the Hurricane heater that did not have a 120V element in it. However it did have an electric water heater, located in the same bay, directly above the Hurricane that may have a direct correlation to the AquaHot 120V element wiring circuit.

Gerald

[Edward Buker]

Gerald,

The schematic did not show the water heater, just the Hurricane Heater, but it used a 10GA wire which indicated to me that it went to a heating element in the water heater that they chose not to show. What was important to me is that the schematic did not show any J boxes or any other point to point wiring so that I have just a couple of wiring connection locations to check out. Always something...thanks for your insight.

Marty,

That is a good point about the current cutting off when the hi temp limit is satisfied at 190F. After I checked the current and found it to read zero amps, I then checked the heater and it was cold so I knew ther was trouble in River City....

Later Ed

[Edward Buker]

Problem Fixed.......It turns out that the wiring that couples the Aqua Hot to the coach wiring is a wire nut connection in a very small compartment in the Aqua Hot. The Aqua Hot has stranded wires and the coach has non stranded. The wire nut on the neutral line was never really tightened and the stripped portion of the stranded wire was very short. It was taped over as it should have been and that was all that was holding the wires such that some contact connection was made. It was clear that some poor connection arcing had occured over time. It is a tight area between the wall of the compartment and the Aqua Hot 120V wiring compartment with limited visibility that probably led to the problem. This is a place to check before you assume that the heating element gone...all is well that ends well.

Later Ed