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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 953
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I have replaced defrost board and sensor on a XP-14-036 and

Customer Question

I have replaced defrost board and sensor on a XP-14-036 and it still ices up .What to do ?
JA: What's the make and model? And can you guesstimate how old it is?
Customer: Lennox Xp-14-036. About 6 years old.
JA: Do you plan on doing the work yourself?
Customer: yes
JA: Anything else we should know to help you best?
Customer: I am a heat pump contractor
Submitted: 9 months ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 9 months ago.

Hi I'm Brian and I'm here to help!

Let me find the defrost board for that unit and I'll be right back.

Expert:  Brian HVAC Guy replied 9 months ago.

Ok, just had to refamiliarize myself with that board. Of course the first thing to do (and I'm sure you've done it) is to make sure the refrigerant charge is at proper level. If you've replaced the defrost board with the OEM board, it is a true demand defrost control and should defrost properly if all other components are ok. Did you replace both sensors? If the outdoor ambient sensor is bad or way out of range, the defrost board will default to time defrost mode and that could be your issue. Check the sensors, make sure they're reading accurately. This Manual shows a temperature/resistance chart in figure 5 on page 5. You can also set the termination temperature jumper on a higher setting and that may help. The default position is 50, you could go up to 80 or 90 and see if that corrects things.