York Defrost Board

[Rafael Nowning]

Ina previous post, I mentioned that control boards are replaced and there is really nothing wrong with them. In recent months, there has been an increased number of defrost boards from split system heat pumps returned for warranty. In-house testing of some returned boards has found that a majority of the boards were not defective.

The following information will help you better understand the operation of the board, and give some insight to other possible sources that may lead a technician to condemn the board when it is actually not defective.

These defrost boards have an internal five-minute compressor time delay that will be initiated anytime the room thermostat satisfies or the high pressure switch opens. In regards to the time delay, one thing that has been seen is that if there is a problem with the compressor contactor coil (such as being shorted or pulling in rough, or sticking occasionally) the board will have a tendency to go through the five-minute time delay, attempt to energize the compressor contactor, but will immediately return to another five-minute time delay and continuing repeating the time delay.

Yes they did allow me to return the board back found that the new board want in to defrost either Iplace the pin cause board test mode go into defrost did work for what they show me. So I decide to go with ICM defrost board it work I just return Lennox back for refund the were not happy say when temperature were 54degree it want go in defrost that is crazy should be able to still jump test pin to make it in defrost mode with in 5 to 21 second if please I formed me with more information , thank You

flash code 2 is high discharge PRESSURE (over 400 psi) I would look to see if you have a problem with the OUTDOOR metering device if it is a TXV. If itis sticking shut, the pressure will climb. Also, indoor air flow is important

Hey Jason I came across a problem like that I found out you got to determent the pressure low side and high if your low side drop in pressure then you have a fault Txv replace Txv. That one solution the next solution is check indoor coil from being block air flow clear or clean the fins,the next attempt to see it if being over charge recover some the freon.one these 3 solution should clear you up .

BTW, next day after the tech was here, I began to hear a rattle seemingly coming from the compressor or very near by that can be heard at the air handler inside as the noise is transmitted along the refrigerant line.

I confirmed from the pub that defrost initiates no sooner than 40 minutes of accumulated compressor run time after the previous defrost cycle and ONLY IF the difference in outdoor coil temp and outdoor ambient temp calls for defrost. My concern is that each time the 40 minutes of accumulated run time passes, the unit defrosts without fail, even with little or no frost buildup, even when the ambient temperature is just below 50 degrees. (It refrains from defrosting if the ambient temp is above 50 as the manual says it should).

My just replaced unit had the old style timer defrost mechanism and was set at 90 minute defrost intervals and worked fine that way for years. My concern stems from that experience; my understanding is that demand defrost is more efficient implying I would be experiencing less frequent defrost cycles with this new unit, not twice as many!

I have a very old York model EICPO30AO-6a and it quit defrosting, after inspecting I noticed the tube that goes into the evap coil is missing off the defrost timer , can you supply some info on how this set up works . Had a new main board about 5 years ago.

The main board replacement was a direct cross , no mods ,no time temp adjustment , the defrost control is mounted on the front panel section with the tube port on the switch. So I can test the defrost control with a vacuum pump ? Dealer did say way back this was a weak link . is there an update for this . The tube is probably inside the condenser somewhere .

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