Community Forums

Les1951 · 10-07-2020, 01:45 PM

In my on going battle to eliminate gremlins from dash air conditioning, I noticed with the A/C off and the temperature set to minimum the air from the vents is at least 10* warmer than ambient air. The same with the recirculation open or closed. Does anyone get cool ambient air through the forward vents ?

Skip426 · 10-07-2020, 01:54 PM

Your problem sounds like the coolant flow control ( ranco valve ) isn't full shutting down .
NOTE: Even with the valve closed it can take several mins for the heater core to fully cool .

Many members have placed manual shut off valves in the heater hoses to aid dash A/C operation.

jestal · 10-07-2020, 02:23 PM

my memory is that the ranco valve/switch is in the AC return line and that is what turns the AC compressor on and off based on the thermocouple attached to the evaporator core.

The Entegra system does not have a valve to turn off heater water automatically like some other systems do. The heater hot water from the engine circulates all the time I thought. Putting a manual shut off valve in the heater lines would be a good idea though as it would definitely take heat out of the combo heater//evaporator core. I've made a note to do this on our coach

There are shut off valves in the heater coolant lines from the engine but they are in the rear of the coach underneath the engine. had to even find them with all the plumbing back there sometimes. they are really only meant to keep engine coolant from spilling out the heater core ports until the heater hoses are hooked up. they are manual valves and not readily accessible but they could be used to stop heater water flow in the warmer months I guess if you don't mind crawling under the coach to get to them.

jestal · 10-07-2020, 02:32 PM

Quote:

Originally Posted by Les1951

In my on going battle to eliminate gremlins from dash air conditioning, I noticed with the A/C off and the temperature set to minimum the air from the vents is at least 10* warmer than ambient air. The same with the recirculation open or closed. Does anyone get cool ambient air through the forward vents ?

Our coach acts much the same. The air pickup for the vent is the two rectangular openings in the HVAC case visible when you open the front cover and look at the back of the dash up above the generator. Those openings not only let in dust and dirt swirling up behind the front cap (especially if the generator is running) but they let in hot air that is likely warmer than ambient due to the sun load on the front cap an/or heat from the generator if it was running. Those openings close when the mode switch is moved to max AC. Any other position they are open for air intake and pull in dust and dirt and warm air.

I put a piece of hooked velcro around the perimeter of each of the holes and cut a piece of the air filter media used on the inside air returns. It sticks to the velcro and works as an exellent HVAC inlet air filter. Only necessary on the classics as I believe the new coaches have an inlet air filter.

Les1951 · 10-07-2020, 03:28 PM

We have replaced the hot water valve, it seems odd the AC needs to overcome a +10 F degree over ambient temperature to cool. I suspect after a new condenser, expansion valve, hot water valve, compressor function test, and $4,000, it all boils down to a refrigerate leak... How tough can it be to find a leak ? We have put dye into the system and had it worked on 4 times [emoji35]

Les1951 · 03-16-2021, 06:23 PM

Well, today we took the coach in for another attempt to fix the dash air conditioning. First they inspected the system with a black light and found evidence of leaks on the compressor, and dryer. They installed a new compressor and dryer and tested the system. The temperature at the vents was near 100* which was 10 degrees above the ambient outside air of 90*. Using a thermal sensor they found the temperature at the condenser to be 30 degree’s different, which indicates normal operation. Further investigation determined the hot water valve was not plumbed properly (backwards) This valve had been changed at NIRV, but the tech here thought it was likely installed incorrectly at the factory, and NIRV probably put it in the way it came out. He had seen this before on Entegra’s and Newmar’s.
So it appears likely I had three problems, an improperly installed hot water valve, an internal leak in the compressor, and a bad dryer fitting. It is working very well right now !
This system had never cooled well. The vent air was always warmer than the outside air, and the cooling was always marginal. I hope this helps some of you guys with your trouble shooting !

Nowabeachbum · 03-16-2021, 06:51 PM

Well, I guess I’ll put my black light away![emoji3] Our heater control valve was plumbed backwards too. It showed up as soon as the temp in the engine built up and then suddenly the ac was blowing hot air.

Gary.Jones · 03-19-2021, 11:59 AM

Suggest going to a company that specializes in truck and trailer air conditioning and refrigeration systems. I had much more luck with a specialty shop than I did with an RV repair facility.

Gary