A/C NOT WORKING REPAIR.
being a victim of no cold air in my coach. i added a can of freon and it did not work. after research it is shown that the control valve for the hot water to the heater core is the issue.
there is a control valve that is the main culprit, please refer to the link from:
this is a complete service manual from evan-tempcon, the supplier of most motorhome a/c units. the service manual indicates also the the water control valve is the issue before any other service is to be done to the a/c unit.
i purchsed a new control unit from ( comfort air in grand rapids michigan, https://www.comfortairgr.com
they were helpful, friendly and had the parts in stock, it was $170 delivered, picture shown below,
it is super easy to install, the photo show it is above the battery and had 2 normal hose clamps used for installation ( credit to thor on this issue.
i did not drain the radiator the high location had very little loss of coolant, ( about 1 pint) took less the 20 min to install. getting the right screw driver took most of the time.
testing the result was more of a weird issue. to check the hose connections i had to turn on the heat for water to flow to both sides of the valve.
after getting normal engine temp. and plenty of hot air out of the dash vents, the a/c was turned on,
it took a long time to get cold air out of the dash vents
why? the heat setting had heated the the ventalation up to engine temp. it took about 15 min for the a/c unit to cool off the "ventilation core- box- air handling unit"
***if you do not wait long enough you can think the valve repair did not work****
then i had ice cold air and this was with the coach not moving just using the fan to draw air ( not best )
PART 2: WHY DID THE VALVE BREAK??
below are a bunch of photo's of the valve being taken apart for research.
there are 2 issues for failure of the valve, both are minor and could be serviced putting the valve back into use again
the large bull gear ( largest white gear) has a o-ring at the bottom between it and the actual control valve, this o-ring broke into 2 pieces jamming the gear. ( this gear will turn the valve). the o-ring is a dirt seal so i did not have any coolant leak.
the valve was stuck, the valve is a simple ball valve design. debris from coolant had lodge into the valve causing a sticking condition. washing out the valve removed debris and allowed valve to move freely. i can assume that most coaches sit for long periods and many probably never get there heating systems really used,
the lack of use of the heating system means no water flow to clean out debris/sludge.
so a habit of turning on the heater for awhile will wash out the valve .
on the road service??
if your valve goes bad during a trip can it bee serviced on the side of the road?? yes, the circuit board / gear section could be removed and the valve turned manually.
with the broken o-ring i could not turn it with my fingers, the valve when removed from control section also could not be turned with my fingers, but after cleaning i could. small pliers was all i need to move a clogged valve
comments on photos
broken o-ring and large gear shown
control unit with circuit board/gears and valve separated
gear box and circuit board
valve location in engine compartment
the new valve
all the pieces ( yes it went back together)