Aqua- Hot Rewire

[Ck2hans]

Spent sometime bonding with my Aqua-Hot and now understand why the living room is always so hot (even with the AC on). As built by Aqu-Hot the #2 pump which is designated for the living room area (in my coach) is also the stir pump. What that means is whether or not the living room heat is on or not, if the Aqua-Hot is running it uses the #2 (living room) pump as a stir pump and circulates hot water through the living room heat exchanger then back to the tank. Living room heat exchanger fan DOES NOT come on under these conditions (#2 pump running as stir pump). This ends up creating a lot of heat in the living room area after awhile.

In my mind (which is a scary thing) if I can rewire the system to make the water bay heat exchanger come on as the stir pump instead of the living room pump it would solve the heat issue in the living room.

I have attached the wiring diagram from my unit, problem is Zone A pump is actually the wet bay pump and zone B is the living room pump in my coach. My knowledge is not enough to know if just switching the in and out heating hoses from zone A pump to zone B pump would fix the issue or if rewiring would be required or perhaps both. My inclination is switching hoses alone is not enough because the living area and wet bay are on different thermostats.

My comprehension of electrical systems is limited, maybe someone could clarify a solution in laymen's terms for me.

Thanks in advance
Chuck

[Gil_J]

Why in the world would you have a pump always on? That makes no sense. Don't you have a main Aquahot control switch inside the coach? If your coach still has the plumbing drawings,see what Featherlight intended.

[Ck2hans]

A Stir pump is necessary for proper operation/circulation of water while the burner is running and heating the tank. When the Aqua-Hot burner is running the water needs to be circulated in the tank to avoid hot spots, hence the need for a stir pump (a Aqua-Hot word). The newer Aqua-Hot in the Tiffin I owned had a separate pump for a stir pump. I guess the older units use one of the existing pumps.

I did resolve the issue by moving the pump, heat exchanger, & thermostat wires around to change what pump, & heat exchanger comes on as a stir pump while the burner is running.

Chuck

[freds]

A Stir pump is necessary for proper operation/circulation of water while the burner is running and heating the tank. When the Aqua-Hot burner is running the water needs to be circulated in the tank to avoid hot spots, hence the need for a stir pump (a Aqua-Hot word). The newer Aqua-Hot in the Tiffin I owned had a separate pump for a stir pump. I guess the older units use one of the existing pumps.

I did resolve the issue by moving the pump, heat exchanger, & thermostat wires around to change what pump, & heat exchanger comes on as a stir pump while the burner is running.

Chuck

Hmmm, are you sure that there wasn't a summer valve somewhere in the system to bypass the toe heater? (Just guessing)...

[Gil_J]

Unless the only call for heat is domestic hot water, then at least pump will be on. I guess I still don't see the need. If a pump must run and none are being called to support a heating zone, I wonder why they don't have a solenoid controlled loop so heat doesn't have to go where it's not needed.

Thanks for the education.

[Joe Camper]

I was under the impression that there were paddles inside the vessel that slowly rotated and circulated that water but I guess that's not right?

[Ck2hans]

Service Manual - Stir pump.pdf

See attached page from service manual.

Mine was plumbed wrong, Zone B was used for the living room and Zone A was used for the fresh water bay. Rather than opening up the system and replumbing it I switched the wires on the relays (A & B) for the pumps and heat exchangers so now Zone B is the living room & Zone A is the fresh water bay (see wire diagram in first post). Also had to move the wire coming from Diesel Burner C-plug (8 Pin) from Relay B pin # 6 to Relay A pin #6 (again reference wire diagram in first post).

I am not to good with electric systems so this took a lot of sitting and staring at the drawings and the system, then some holding my breath once I changed it and turned it on. Apparently I did it correctly, it's working

Chuck