Lennox Diplomat Seems like a circuit board problem. Full of freon, blower runs, wants to freeze up. New in 1994 Can I still buy a new circuit board somewhere?

hat is the compressor atop the engine.
you skipped step #1
0: new compressor put on ( has oil with or not? oops.
1: do vacuum leak down test. if fail and did, fix this now.
2: pull a full vacuum max, for 30mins. (tool called pump vac
3: put in the freon, by weight, and test it, using manifold gauge per the manual, on car. (service man)


off hand blind , wrong pump or wrong port adapter.

Generally sounds like they are thermostats

Take it back. If the new one doesn't perform like it should get your money back and buy a Stihl. They will fuel and run the machine before you ever leave the dealer with it to make sure it runs like it should and they can answer any questions and even get you parts. Husqvarna may do the same thing

If you need further help, I’m available over the phone at https://www.6ya.com/expert/kelly_69a0cf1b13789df1

I would buy another board. The boards contain safety features.

Your control may a defected relay to the blower under heating mode. If that is the case you will need a new control board or replay.

open in resistor w/ standard hvac. contorl module w/ auto hvac.
test all and the blower motor itself

You mean a wiring diagram? Blower problem or Compressor doesn't come on? Is it full of freon? Does the compressor come on if you jump the low pressure switch?

theholts220 - Sounds like they needed to install a bit larger transformer . You can also buy a A 50 Sensing relay that attaches to the wires for your motor and when you turn on the furnace it will allow the power to go to the humidistat. Very strange though they do not use a lot of power. Check and make sure the wires are not pinched or touching metal somewhere.


TLuzzo - The humidistat seems to be working when you turn it down. The wires for the solenoid should be hooked up to your furnace circuit board. The instruction manual will tell you where. If you dont have a spot on your circut board the A 50 sensing reley is they way to go. They are inexpensive

The contactor on the outside unit is sticking and must be replaced. The inside unit cycles off and the outside continues to run causing the refrigerant lines to freeze up.

Found system was slowly loosing coolant through a variety of miniscule leaks in rusting part of condenser. Apparently coolant level had dropped sufficiently in the blower repair interval to where the system no longer functioned with adequate efficiency. Bottom line - low coolant level as is the first suggestion in most related ac repair forum sites. I'm buying a Trane, this system is no longer economically feasible to maintain.