AquaHot Plumbing Problem

[Lee Bornstein]

Have 2000 Monaco Executive with AquaHot baseboard type heating.

AquaHot unit functions normally.

There are three zones, each with its own pump and return line.

Bedroom Zone and Bathroom Zone work perfectly.

Living room zone has three heat registers, two on slide (Galley toe kick and under sofa) third is under dash.

Cant get any hot water to Living room zone - pump is running but water doesn't flow. tested each heat exchanger for blockage by disconnecting them individually and bypassing.

Removed and tested check valve and that too is OK. Primed Living Room Zone pump and that pump is building pressure in the supply line to the heat exchangers.

Since there's 3 exchangers (2 on slide) my guess is that there's a T to split flow to the Slide and to the front unit.

Have examined all piping on slide and see no problem there.

Can't trace piping from AquaHot unit since it is threaded through the coach frame then appears in the slide and in the front of coach.

How do I troubleshoot this further?
Called Monaco and they're no help - they don't have documentation on coaches built before they reorganized after bankruptcy.

Would like to get this fixed so we can do some dry camping before summer.

Any Ideas???

Lee

[vito.a]

Do the fans come on?
If not, then it may be a thermostat issue. You could try swapping the two thermostats. Do you still have the old 4 button Duo Therm thermostats as they can be problematic.

Then I would try swapping the pumps from a good zone to the bad one and see if that fixes the issue.
I would also look at the Aqua Hot plumbing where it enters the slide out. That's the most likely point for a kink or blockage.

Just a couple of side notes. Most Monaco coaches are set up with zone 1 up front, zone 2 in the rear and zone 3 in the center bath area.
Also, Aqua Hot was a very expensive option ($10-12k) for the original owner.

[Lee Bornstein]

Fans do come on - new thermostat in front.
Checked plumbing in slide - all ok.

Pump #1 for front zone is working and building pressure.

If there were a Kink on slide then front unit would still function since coolant to that exchanger doesnt go through slide.

Lee