Skip to main content ↑ ↓
Topic: Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine (Read 638 times) previous topic - next topic

Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine

I have a problem with our aqua hot heating system. When we turn on the heat only the back blows out hot air, the front blows out cool air. If I run the engine the defroster blows hot air but the panel on the cabinet behind the passenger seat still blows cool air. I assume the reason for this is the couch uses the hot water from the radiator when the engine is running for the defroster. I have tested the hot water and it works. We have replaced the front AC a few years back we don't use it very often when it is cold enough to require the heater but I think it worked fine before we winterized the couch in the fall of 2024, we had a friend stay in it this spring and it didn't work. Due to lots of things this is the first time I have had time to try to troubleshoot this problem. Any ideas?
 We have 2003 U320 Build #6206 Duo Therm 5 button controller
John & Holly Zick
2003 U320
38' Build #6206
FMCA F495485

Re: Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine

Reply #1 –
Aquahot zone valve for the front zone could be stuck closed, so fluid isn't able to circulate.  You can try "percussive maintenance", aka tapping on the zone valve, to see if it opens.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine

Reply #2 –
John, call me, Rudy Legett.
7 one 3. 8 one 8. 3234
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine

Reply #3 –
Hi Rudy, This is actually Holly John's wife. Sorry for the late reply, I had dog agility this afternoon and then we went out for dinner. I see you are off line right now. I can call you tomorrow AM if you give a time that works for you or you can call me at 262.993.5103. I am usually up by 0730 Central and I will be home until around noon.
John & Holly Zick
2003 U320
38' Build #6206
FMCA F495485

Re: Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine

Reply #4 –
Call after 8 am till 8 pm central time.  It would be helpful if you are at the coach with the cover over the burner removed.

A volt meter set to dc volts, 0 to 20 vdc scale with one lead grounded.  The heater case is ground.

Plus a hammer or a large wench nearby too.

Call me then

Update, had a nice phone visit with Holly.  Turns out the pump would not run when powered up.

Another update, pump has started to run.  So she will see if it stays that way.  Yea, I hope

Holly is very good with her tools, Bravos to gal
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Aqua Hot Problem Front part of Coach blows cool air out, Rear works fine

Reply #5 –
Well the pump continues to run however there is still no heat the hose coming out of that pump is cool and the others are hot so even though it is running it is not pumping anything so a pump is on order. Thank you Rudy for your help you are the best.
John & Holly Zick
2003 U320
38' Build #6206
FMCA F495485