Community Forums

totohawki · 02-02-2011, 04:21 PM

We have an AGS system in our coach with a Comfort Control thermostat for our heat. When it is too cold for the Heat Pump, it is supposed to go into Aux Heat and start the furnace. We have had many repairmen check this out and can't find the problem because once in awhile, it will actually work.

It was suggested with put in a thermostat just for the furnace and operate it separately from the main thermostat.

Does anyone out there know what the problem is and if putting in a separate thermostat is the right thing to do.

Thank you

takepride · 02-02-2011, 11:54 PM

Toto:

Welcome to the forum!

I believe you may mis-understand the AGS system's function. The AGS will start the genset, when properly configured, when the thermostat calls for air-conditioning. It doesn't work for the heat pumps or the furnace. It is designed that way since AC is required for A/C. The furnace uses only 12 volts and needs no AC. The heat pumps use AC, and are part of the A/C units, but do not operate with the AGS.

To use the AGS for the air-conditioning, you set the thermostat to "Cool" and the AGS to trigger the genset when cooling is called. BTW, the genset will start whether you are plugged in or not (rather annoying). It can be wired, with relays to verify that there is no shore power, before triggering the genset (actually bypassing the signal when plugged in).

Hope this helps.

AC= Alternating Current
A/C= Air Conditioning
AGS= Automatic Generator Start

Old Scout · 02-03-2011, 07:15 AM

You didnt mention the year and model of yr coach but this is how it all works on my 03--hope this will help...First-- AGS is associated with the generator autostart and A/C, so not really an issue here. Second--your propane furnace is "slaved" to your front heat pump and thermostat, so your rear heat pump is not involved in the switch-over to propane [regardless of setting]. Third-- heat pumps tend to vary as to when they lockout from cold temps and go to aux. so its hard to tell when this system is actually working. Mine tends to vary quite a bit so it has to be in the low 30s to high 20s before I can be sure of the switch-over. Accordingly, I try to monitor the front system during the night [light sleeper] and when I notice that the front heat pump is going to defrost mode on a frequent basis, I manually switch to the furnace. Realize this is kind of a flaky answer but .....

Wayne R · 02-03-2011, 03:14 PM

Old, That is what i have found also. The cut over is past the point that I am willing to wait for. The system is good in theory but does not work well enough to keep the coach warm. Mine has Hydro Hot but the cut over would be the same.

takepride · 02-03-2011, 11:04 PM

Okay OS, now let me get this straight.

If the front heat pump is set to run on the thermostat, and the temperatures drop to a point where the heat pump is no longer viable, the thermostat (or brain) switches, automatically to an auxiliary mode, which signals the propane furnace to operate?

I haven't tried this, since I cannot stand how loud the heat pumps are. When on umbilical, I use ceramic heaters and when boondocking, I use the propane furnace. If it's really cold, I use both.

But the thought is nice....

Old Scout · 02-04-2011, 06:48 AM

Yup--that's how it works, but again, only with the front heat pump, and only after the heat pump has determined that the ambient temp is nolonger "viable" to extract heat. For example--it was 32 degrees in Lafeyette La last night and our pumps ran fine all night. Currently waiting for ice to melt!!!!!