Please try to measure your 24 volts at the reversing valve with an analog voltmeter;not a digital meter. Before this beats you up, try an external 24 volt supply to the valve. @4 volts should give you cool no 24 volts gives heat.
Originally Posted by dback
Some good advice has been given.
You can also :
-rv engergized in cooling , you have 24v at rv coil , unwire coil and do a continuity check.
-lightly tap on ends and side of rv with 24v present.
-new rv's are china and junky. Ranco seems to be long gone. They have a poor material for the piston and can be easily frozen during the brazing process. The capillary lines are also problematic.
-if the coil checks good and you have voltage , but its still in heat , then bad valve.
-if it changes over while tapping on it , then you still have a bad valve , but it is now cooling.
-this is a new unit warranty situation , if it were not then adding SUPCO oil and allowing to circulate through for a while , then tapping on the valve very patiently over and over will work about 60% of the time.
-also the china bodies are easily distorted during heavy handed installation and it takes very little runout to cause a piston to bind.
If you do have to replace the valve under warranty you can :
-pump out the unit by closing the liquid line valve and watching your suction pressure by connecting to a true suction port inside the unit. (since it is stuck in heat)
-when installing the new valve what works well is to carefully coat the entire valve in heat paste , then wrap in wet rags and have a helper add droplets of water to the wet rags during brazing.
-use a relatively high heat to braze as quickly as possible.
-you can cut the old valve out with long stubs and bench braze the stubs using the method on a work surface , then use couplings to install the new valve in unit.