Community Forums

greggstout · 08-22-2020, 08:02 PM

We just picked up our new (to us) Monaco Sig. It has 3 roof air conditioners with two thermostats. The front living room is supposed to be a zone on the front thermostat, and the hall and bedroom supported as zones 1 and 2 by the second thermostat located in the bedroom. When the front A/C is turned on, it is very loud in the living room area, and a fair amount of air circulates cool, not very cold, air. When the front is off, and the rear is turned on, the front appears to still comes on, though the thermostat is off. There is never a strong airflow from the ducts in the bedroom, nor in the hallway. Without climbing on the roof and observing the units come on, I suspect the do not. I'm wondering if the RV lot wired both thermostats to the front unit, and it is the only one working. Any thoughts and experience would be helpful.

Gregg Stout

K7JV · 08-22-2020, 08:23 PM

I would expect significant similarities between your Sig and our Dynasty, both '06's. In ours, there is a central duct that runs nearly the length of the coach. The front heat pump "feeds" into that duct about 4' or so behind the front seats. The mid-coach heat pump "feeds" into that duct about 3' or 4' forward of the back wall of the front living area. The bedroom heat pump "feeds" into that duct above the bed. There aren't any dampers to control the flow within that duct, so the tendency is for the bulk of the airflow from each of them to discharge closest to the unit, but there will be a significant but decreasing amount thru the vents as you move towards the front and rear extremes. It is a very poorly designed system from an engineering standpoint.

I'm expecting you have the AquaHot for your "furnace" heating. That is very much zone by zone as the heat exchangers are contained within the respective coach living areas. In our case, the front thermostat essentially controls the forward living area. Zone 2 on the rear thermostat controls the bathroom, and zone 1 on the rear thermostat controls the bedroom.

We have found that the zone 2 heat pump works pretty well when operated along with the front thermostat heat pump to keep the front of the coach pleasant. The rear zone 1 actually does pretty well with the bedroom.I tend to think of the front one as being front living area, the middle one being "whole-coach" support and the rear one being the bedroom. We find nearly zero value from the heat pump in either mode, in the bathroom, as it is on a spur duct from the main center duct. That is a shame, too, because the temperature probe that senses the temperature that it is controlling to is located in the bathroom. So the control feedback loop is seriously compromised.

One other thing to remember is that whatever MODE you select for zone 2 on the rear thermostat will be the ONLY mode that will operate in the bedroom area. In other words, you can't run zone 2 on the A/C or heat pump and zone 1 on the AquaHot. Zone 2 rules. I find that extremely frustrating much of the time, but we've lived with it for 15 years. You should know about that little (big?) quirk, though. Kind of a bummer, though, as we like a cool bedroom and a warm bathroom.

Post any more questions you may have about the HVAC on your coach and there should be many on the forum that will have good information for you. Cheers to you, and enjoy that new-to-you beautiful coach!!!

JJTL · 08-22-2020, 08:43 PM

Well explained, K7JV! Not much I could add to that excellent summary. We find this to be true on our coach as well. The mid unit is the “whole coach support” unit as you say.

So I will just say welcome to the forums, Gregg! You’ve come to the right place. As you’ve witnessed already, a wealth of knowledge and expertise here.

Glad to have another Signature owner among us.
All the best!
Josh

kenwyatt · 08-22-2020, 09:44 PM

Would agree with all the above. The duct design is terrible. Mine has a register in the closet that robs air. Also the bathroom register gets very little air due to the design. Also pull your registers and be sure there are no leaks between the ductwork and ceiling panel allowing some air to go into the dead area above the ceiling. Pulled all of mine and found leaks. Helped to seal them with foil tape. Also the biggest bang for the buck was to go up top and replace the insulation inside and outside of the plenums. Posted pictures on one of the threads.

hypoxia · 08-23-2020, 08:50 AM

On my '07 Signature Rear Thermostat in A/C mode Zone 1 Bedroom (Rear) and Zone 2 Galley (Middle). When in AquaHot, Zone 1 is Bedroom and Zone 2 is Rear and Middle Bathrooms.

Repair history was showing a constant rear A/C airflow problem. I removed the rear closet A/C outlet grille and could see outside. The rear duct had never been capped at the end. Airflow is fine after capping it.

You could lower the ceiling covers for the A/C inlets and have access to see the ducting and whether it needs taped with metal tape to seal it. The filters probably need cleaned anyway. While in there look for the "phone" A/C data connectors. They probably need cleaned as they are a common source of HVAC problems.

When you finally get on the roof my suggestion is to check with a meter for the capacitance values of the A/C units. No meter? Either get one or replace all capacitors (not made in China) and PTCR's on principal. You won't regret it in the long run. Also spray the coils clean on the A/C units.