Got a universal under dash AC-- HEAT unit with 3 speed fan switch and a low to High temperature switch-- AC is very cold using above switches on AC unit panel---- But now I need a set-up to make the heat work--the hot water hoses are tied in direct in back of unit in and out now hot water is running thru heat coil all the time-- seems like I need a water valve and a switch for heat---What do you suggest who had this set up and what parts did you use--info on parts used and pictures-- Thanks
English cars had cable operated hot water valves as well. Doubt they would be cheap. Even though they are English they won't leak oil but can't say about water.
Get a cable control valve (see pic). They have vacuum control valves too. May have to pick a vehicle to find what you need.
I understand about the inline hose valve--WHAT makes the unit know it is time to get heat on as of now it only has cold air I got to be able to shut ac off and SWITCH over to HEATER-- got to know what kind of separate switch set-up I need -- looking for what separate set-up is needed to just turn heat on ? ? I have cable heater valve installed all that does it shut it off in summer-- I need a separate switch or set-up to just turn heater on and isolate AC side ---
I put water cut off valves in BOTH of my water lines to the AC/Heat unit... makes AC that much more efficient. I open both valves in the winter... might be overkill but when trying feel AC in a convertible you need all the cooling help you can get. I normally use the valve given above by hot rod37 or one very similar.
If the heater core and A/C evaporator are in the same housing sharing the same ducting IMO to run A/C you must have a switch to activate the clutch on the compressor. For heat you just need to let the hot water into the heater core through the previously mentioned water valve and turn on the fan. Your A/C switch is A/C when on, heat when off.
Hotrod 37 is faster than I am, I've had the Ford truck heater control valve saved on my Ebay watch list for years. FORD E & F SERIES & BRONCO HEATER VALVE C3UZ18495A YG133 STYLE, 1 YEAR WARRANTY | eBay They are easy enough to find at your favorite local parts house though .
I walked into my local parts house and dug through their valves until I found one that fit what I needed. I'm nobody special, they don't know me, but if you ask with with confidence they'll usually let you look. Devin
Look at the print/instructions of your unit. I’ve personally never seen an under dash AC unit which also had a heater exchanger inside, but if yours has both there must be a knob, level, etc on the front to activate the heater which deactivates or locks out the compressor clutch. I’ll bet there is a a wire that’s for an electric valve you install on your engine whether it be screwed in to the water pump or intake or inline in one of the hoses Aftermarket complete systems have electronic valves which when in the AC mode continue to circulate the hot water thru hoses but not to the inside evaporator using a bypass system.. I’ve included a photo of mine for an Old Air Products combo unit. No engine coolant circulates or dead heads at the interior unit unless I select the heater. You definitely do not want to blow thru a hot exchanger to then go thru the evaporator trying to cool you.
NEVER no directions with unit that would be easy--- in the back as in picture 2 ac Connection and 2 hot water connections--- on front panel is the 3 position fan switch and other Temp switch is LOW or rotate to High-- AC works perfect compresses and Trinary switch all working PERFECT----- But need a switch to tell the unit AC off turn heat on ---
That old air products heater valve is a Mopar valve. Some searching suggests that your unit may be a very close relative of this Cold Master unit. A/C KIT UNIVERSAL UNDER DASH EVAPORATOR / HEATER AIR CONDITIONER 450 COMBO W/ ELECTRICAL HARNESS – Cold Masters INC (coldmasterinc.com)
With the compressor off the ac will not get cold. For heat ope the hot water valve. Turn on the ac switch and all will be good. The water valve must be in the pressure side of the water pump.
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