Cruiseair Solenoid Coil question

[Sailor John]

Good day all,
I have been trying to diagnose the non-functioning heat side of my Crusiair 16K AC. (The cold side works well). This is the AC unit that serves the main salon. It is not going into heat mode when the thermostat is turned to heat. No click, no whoosh, nothing. After some beneficial research through this web site, I was able (gratefully) to ascertain that my coil (that makes the solenoid work) may not be functioning. When powered up in heat mode, it does not cause the solenoid to move and there is no electric current creating a magnet in the coil. I traced and checked all the wires and everything seems to be fine.
My question is, does anyone know where I can get a replacement coil? I have attached a picture with the relevant details stamped on the coil bracket.
As always, I appreciate any suggestions.
Thank you all,
Sailor John

[KPTIM]

Hi John,
You need to make sure the coil is good or bad for sure bad. The first check is to measure the resistance of the coil winding. Disconnect it from system and use an ohm meter it will read almost a short (just a couple of ohms) if it's good and of course it will read an open circuit if it's bad. Do not try to power the coil up if it is not on the valve (it needs the metal slug in the valve to keep the inductance right) or it will burn up.

It is possible that the heat side of the thermostat is bad. In this case the AC cool will still work. On the older Cruiseair thermostats there is a dead band between heat and cool desired setting.

Of course the refrigeration transfer/reversing valve can be stuck (the internal plunger that the coil moves). If that is the case you will have to make a decision about how much money to put in an older system to replace the valve or the entire compressor/condenser unit.

I may have one at the house if your coil is bad and you can't get it from Cruiseair.

Post more or send me a PM

Tim

[Reefgeorge]

Measure the behavior at the leads going to the coil when there is a call for heat to see if the system is trying to move the valve. Also on my system you hear a click right before the compressor starts for cooling which is the reversing valve equalizing the pressures before the compressor starts. I am not sure if those older units start that way.

[Sailor John]

Hello again. I really do appreciate the assistance!
I did the ohms test on the coil this evening. It showed .18 . So it's not open, but I don't know what it should read. Next, with the compressor running and the thermostat in heat mode, I tested the 2 wires that go to the coil. There was no power showing.
So....
Now I am wondering, might the T-stat be faulty? Is there a way to 'short' or trick the T-stat into heat mode?
I have enclosed a few more pics: The first shows the ohms test,, the 2nd shows the line test to the coil, and the 3rd shows the top of the T-stat, removed from the wall, but not disconnected. (I noted a very small diameter 'pipe' running from it).
Again, your help is truly appreciated!
Sailor John

[Reefgeorge]

Is there a change in the voltage at the coil leads between call for cooling and cal for heat? I don't know off hand which position is energized.

[Sailor John]

Hello Tim and George (and everyone else too),
My understanding is that the reversing valve is energized in heat mode.
When I put the t-stat into heat mode, there is no action or sound at the reversing valve or solenoid. Nothing vibrates, clicks whooshes etc. (For reference, the other Cruisair unit has definite action taking place. Sort of a Click—Whoosh---Click, then the heat just pours out)
When I tested the leads to the coil in heat mode, there was no sign of power. (See pic #2 in last post). Yet, the coil seems fine through the ohms test (Pic 1).
Is it possible to put power directly to the coil leads to see what happens? Will I damage anything?
Certainly appreciate the help,
Sailor John