I thought I understood the Aquahot

[ShadowBolt]

Now I'm not sure I do. When it's really going to be cold (lower 20's) I set the thermostat to gas at 50 degrees. Zone one and three are turned on. The LP burner and the electric burner on. Works perfect. Sat morning it was supposed to be in the upper 20's so I turned off the LP and left the electric burner on. Just for kicks before I walked out I turned up the thermostat to 55 (it was 50 in the coach at the time) and nothing happened. I waited and waited. Shouldn't the heaters come on even with just the electric burner on? Joyce had told me when we first got the unit that I should set the heat to gas and zone 2 only when it gets central Texas cold. I just don't trust the floor heat that much. Oh and I also keep the basement heat on low anytime I'm running heat.
I guess either I don't understand or my electric burner is not working.

JJ

[loisjop]

I'm not sure on the lp units, but with the diesel aqua hot units the small blowers and the circulating pumps won't come on until the boiler fluid is up to a certain temp. The temp may not be hot enough to turn on the units in cold temps with just the elect unit on. Also, even if they do come on and the temp of the fluid cools they will shutoff and it will take considerable longer to reheat the fluid, before they will come on again, with just the elect element. Noel

[ShadowBolt]

Originally Posted by loisjop

I'm not sure on the lp units, but with the diesel aqua hot units the small blowers and the circulating pumps won't come on until the boiler fluid is up to a certain temp. The temp may not be hot enough to turn on the units in cold temps with just the elect unit on. Also, even if they do come on and the temp of the fluid cools they will shutoff and it will take considerable longer to reheat the fluid, before they will come on again, with just the elect element. Noel

I will go try again and give it more time.

Thanks Noel!

[pasdad1]

Originally Posted by loisjop

I'm not sure on the lp units, but with the diesel aqua hot units the small blowers and the circulating pumps won't come on until the boiler fluid is up to a certain temp. The temp may not be hot enough to turn on the units in cold temps with just the elect unit on. Also, even if they do come on and the temp of the fluid cools they will shutoff and it will take considerable longer to reheat the fluid, before they will come on again, with just the elect element. Noel

X2. Electric only is usually only effective to about 40 degrees F outside temps......need to leave the switch for the burner "on".

There is no need to turn it off, as it will try to use only electric as long as it can - and then only fire up the burner when electric only is not enough.

[ShadowBolt]

Originally Posted by pasdad1

X2. Electric only is usually only effective to about 40 degrees F outside temps......need to leave the switch for the burner "on". There is no need to turn it off, as it will try to use only electric as long as it can - and then only fire up the burner when electric only is not enough.

Even if I only need it to keep the temp in the coach above freezing? If the e-burner will keep it 45 degrees inside and keep the basement above 32 degrees.......

JJ

[rogelling]

When you set the thermostat to Electric what you are doing is turning your AquaHot off and turning your heat pumps on. The Electric part of the AquaHot is controlled by the green switch on the AquaHot panel but that is a back up to gas or diesel furnace. For the forced heat to work either on Electric AquaHot or gas/diesel or both, the thermostat most be on Gas asnd not Electric.

[loisjop]

Originally Posted by rogelling

When you set the thermostat to Electric what you are doing is turning your AquaHot off and turning your heat pumps on. The Electric part of the AquaHot is controlled by the green switch on the AquaHot panel but that is a back up to gas or diesel furnace. For the forced heat to work either on Electric AquaHot or gas/diesel or both, the thermostat most be on Gas asnd not Electric.

He had the thermostat set on gas. Only thing JJ said he had on elect. was the aqua hot element. Noel

[pasdad1]

Originally Posted by ShadowBolt

Even if I only need it to keep the temp in the coach above freezing? If the e-burner will keep it 45 degrees inside and keep the basement above 32 degrees....... JJ

Yes. Remember it is also controlled by the thermostat. If you set the thermostat on 45F that is the temp it will maintain (can you even set heat that low?) If the burner doesn't need to run it won't. You are trying to second guess the system - it knows what it's doing :-)

Without enabling the burner, you run the risk that the coach freezes......if the electric element can't heat the boiler up to its working temperature (and you have prevented the burner from coming on if needed) then the circulating pumps never start, and no heat gets delivered into the coach.

[smlranger]

pasdad1 has it right. I was new to the Aqua Hot system myself when we got our Allure last April. I checked with Roger Berke (he is an expert and has an excellent forum for owners of hydronic heating systems) and he recommends leaving both the electric element and the burner (whether diesel or LP) on if you want to ensure that you have adequate heat. Leaving only the single electric element on with the burner off will make you vulnerable.

Now, with the larger Aqua Hot (600 models) with 16 gallon coolant capacity, they will heat the coach without using diesel or LP in most cases with just the electric elements. However, those models have two heating elements and a much larger coolant tank than ours (5 gallons).

[voltdoc]

Originally Posted by ShadowBolt

Now I'm not sure I do. When it's really going to be cold (lower 20's) I set the thermostat to gas at 50 degrees. Zone one and three are turned on. The LP burner and the electric burner on. Works perfect. Sat morning it was supposed to be in the upper 20's so I turned off the LP and left the electric burner on. Just for kicks before I walked out I turned up the thermostat to 55 (it was 50 in the coach at the time) and nothing happened. I waited and waited. Shouldn't the heaters come on even with just the electric burner on? Joyce had told me when we first got the unit that I should set the heat to gas and zone 2 only when it gets central Texas cold. I just don't trust the floor heat that much. Oh and I also keep the basement heat on low anytime I'm running heat.
I guess either I don't understand or my electric burner is not working.

JJ

JJ, Did you find any resolution for this issue?

Hmmm, in my opinion and experience the answer is yes the heaters should come on for the condition you described. To clarify, for Zone 1 and 3 you should hear the heat exchanger fans come on. For zone 2 you might not hear it, but the booster pump (in the PS wet bay) should come on.

I just tried it on my Aspire (with the 350LP AquaHot) to be sure. Electric on, Burner (LP) off, thermostat set to GAS. Heat exchanger fans come on immediately.

I know someone else mentioned the heat exchanger fans don't come on until the water temp gets hot enough, but that's not the case on the Aspire's with the 350LP Aquahot - at least that's not how it is set up on mine. Probably the diesel burner units are rigged differently, I don't know.

Also, I have found that if you are just using the electric element (burner OFF) and it gets too cold, the heat exchanger fans will just run indefinitely - there are not enough BTU's generated by the electric element to raise the temp inside the coach. That is opposite of your experience.

To troubleshoot:

1) Verify the Water Heater breaker has not tripped - the green light being ON at the switch (12v DC relay circuit) does not mean the electric element has AC power.

2) Verify the green light comes on when you turn on the electric switch for the AH. If it doesn't your electric element will not be energized - get back to me as I had that problem and can tell you where to look for the fix.

3) Check the thermostat fuses - I think there's one in the bathroom panel.

4) To see if you are generating hot water with the electric element, try shutting both electric and burner switches off, let the system cool down, then turn on your electric element and see if you get hot water (from the faucet) after a half hour or so. Alternately, I noticed when the electric element gets the water up to temp you can hear it "sizzling" via the AH exhaust pipe.

If the water is in fact heating, and all the other checks above are normal, from the symptoms you described, I might first suspect there is a thermostat or thermostat wiring issue.

FWIW, we live aboard now, but find the fireplace is a fantastic heating alternative. It has its own thermostat and for temps down into the mid 30's we heat the entire coach pretty comfortably just with that. Our fireplace is located midship. If you have one, it might be a good backup and probably uses the same amount of juice as the AH electric element. Of course that won't help keeping the wet bay above freezing.

[Dr4Film]

Roger Berke is the Aqua-Hot Guru and if you own a Aqua-Hot unit I would STRONGLY suggest that you join his Hydronic Heating Forum.

There is a ton of information on that site, more than you can ever imagine.

Also, for the life of me, I just don't understand what people are thinking who constantly play with their Aqua-Hot switches. Obviously those people don't understand the system.

I have owned the Aqua-Hot unit in my coach since 2003. Since that time, BOTH the diesel and electric switches have been on ALL the time, 24/7/365 days a year, unless the unit is being serviced.

The electric side has thermostats the same as the diesel side does. The electric will keep the boiler fluid at temperature UNLESS the demand for heat or hot water EXCEEDS the ability for the Electric Assist to keep up with the temperature or demand. That's when the diesel kicks in. The thermostats are at settings to allow the Electric Assist to do its thing FIRST and if it can't keep up, that's when the Aqua-Hot sends in the BAD BOY diesel unit to fire up and supply the demand needed.

They work in unison not separately. If one or both switches are off, then it won't work as it was intended to.

My advice is to turn the switches on and leave them on UNLESS you are storing the coach in a warm climate for an extended period of time. If you are storing the coach in a cold climate and don't want to winterize the coach then leave the switches on so that the Aqua-Hot doesn't freeze. If that were to happen, it will cost you THOUSANDS of dollars for a new unit.

Dr4Film ----- Richard

[CoreyinWP]

Excellent post as usual. Thanks!

[glenda1908]

I agree with everything Dr4film stated. Yes, Roger Burkes forum is a great source of information. He helped us out when we were having some problems and pointed us in the right direction. It has been below freezing here in VB for over a week and now we have a foot of snow too....yes in Virginia Beach. We park the Tour next to the house and have kept the burner on since the cold snap and it has kept the coach and basement warm and toasty. We decided not to winterize because we often like to just take off for a weekend when the mood strikes us. Also good to know that the coach is so well insulated. The snow on the roof is still there from yesterday so we know the heat isn't escaping through the ceiling.

[brobox]

Richard, thank you for that informative post. That makes a lot of sense.