Aqua Hot: Zone #4 & Pump #2 lights on all the time

[Newcsn]

Getting ready for first winter trip & checking out the Aqua Hot system. Opened the bay door and noticed that the Zone #4 & Pump #2 lights on the control panel remain lit all the time. The system is off (both diesel & electric) and the interior thermostats are all off as well. Yet, these 2 lights remain lit all the time - unless I shut all power of to the coach. I reviewed docs on Aqua Hot website & couldn’t locate any trouble shooting for this situation. 
 

Any ideas? 
Thanks

[96 EVO]

Is it close to freezing?

It may be your wet bay heat exchanger, which I recently learned can run even without the boiler fluid being warm.

[vito.a]

Turn on your Aqua Hot diesel switch and let it run through a complete cycle.  Then check each zone for heat as well as hot water.  After that check your lights.

[Old Dog]

One pump runs whenever the unit is on to maintain circulation, there is no mention of it in the manual and got that tid bit from a tech. I think it was pump #2, not sure if it varies by system.

[96 EVO]

38 minutes ago, Old Dog said:

One pump runs whenever the unit is on to maintain circulation, there is no mention of it in the manual and got that tid bit from a tech. I think it was pump #2, not sure if it varies by system.

Stir pump.

On my 450D model, that will only run with the diesel burner running. 

Mark has a pump / zone running with no power source turned on.

[Frank Bergamo]

6 hours ago, 96 EVO said:

s it close to freezing?

It may be your wet bay heat exchanger, which I recently learned can run even without the boiler fluid being warm.

I believe it is set up this way so it will keep the wet bay from freezing when running down the road. The engine loop is what heats the fluid even though the diesel burner, electric element and inside thermostats are off.  Hope this helps.

[96 EVO]

1 hour ago, Frank Bergamo said:

I believe it is set up this way so it will keep the wet bay from freezing when running down the road. The engine loop is what heats the fluid even though the diesel burner, electric element and inside thermostats are off.  Hope this helps.

Your probably right Frank!

The problem with that setup is, owners who fully winterize their water system, park their coach without shore power, and the wetbay pump and heat exchanger fan runs cold fluid, doing nothing but running their house batteries down.

Edited January 25 by 96 EVO

[Garry Donohue]

On the subject of the wet bay heater running the batteries down, would it help if you turned the wet bay heater knob all the way down? This hopefully keeping it from turning on?

[Frank Bergamo]

Turning it down will work to a certain degree, but forgetting to turn it back up could potentially cause a problem later on. Ideally, I believe Monaco designed the coach to be plugged in at all time when parked for extended periods of time , preventing battery drain. 

[96 EVO]

Aqua Hot could have supplied a bay thermostat with an 'OFF' mode.

Monaco (and other manufacturers), could have wired it so that the 'salesman switch' shut off all power to the unit.

[Newcsn]

On 1/24/2023 at 11:26 AM, vito.a said:

Turn on your Aqua Hot diesel switch and let it run through a complete cycle.  Then check each zone for heat as well as hot water.  After that check your lights.

@vito.a Thanks for the feedback! Did an annual maintenance, let the system run a complete cycle & we have heat in all zones. However, because we’re winterized I won’t be able to test the domestic hot water side for another week (heading south).

One issue: Even though we have heat out of every exchanger (including the wet bay heater) the Zone #3 light on the control panel never lights. I even cycled on the engine block heater and the light doesn’t light. Any ideas?

Thanks, as always!