Replace Heat Pump Defrost Board?

Macdaddy4738

Macdaddy4738

Well-Known Member
Joined
Jun 1, 2005
My defrost board on my heat pump isn't working right. It doesn't put the unit in defrost long enough. I had my standard HVAC company come out and take a look. They diagnosed the problem and I told them to get the part and fix it. The cost is....high. I really didn't mind it, but the part was supposed to come in Friday and here we are at 9:30 on Monday and I haven't heard from them.

I looked the part up and it seems to be pretty cheap even with the sensor. It almost looks like a plug and play install too. The sensor looks like it just clips on. Is this a DIY item? I'm thinking if these guys don't call back I might just try it myself...
 
Depending on make and model.
They are often just that simple, plug and play.
 
Ron said:
Depending on make and model.
They are often just that simple, plug and play.
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This.
I remember going through this same thing several years ago. I was shocked at the price difference between buying the part overt he shelf at Reedy's vs what the local HVAC guy wanted to charge. I understand markup, warranty etc but it was like 5x the cost. Was just a screw and pop in.
 
Ended up just having them do it because I really don't have the time to be messing with it. Not sure what they did, but it's still not defrosting correctly.

Now the thermostat reads "waiting for equipment" and the unit just shuts off. It doesn't keep the blower fan on or heat strips and it doesn't run the outside unit on AC, it just sits till it deices (and that's only like 10 percent of the time). Sounds like they bought the wrong board. It's a Goodman though, not like some sort of exotic off brand.

This is what it looks like after maybe an hour and a half of run time. I would assume that amount of ice buildup on a 45 degree morning isn't normal?

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What kind of tstat do you have? I haven't messed with the new smart tstats but I also haven't seen one that says it waiting for equipment. how does the tstat know it's waiting for equipment? it's an analog signal to the tstat with no return signal to the tstat.
 
peewee said:
What kind of tstat do you have? I haven't messed with the new smart tstats but I also haven't seen one that says it waiting for equipment. how does the tstat know it's waiting for equipment? it's an analog signal to the tstat with no return signal to the tstat.
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It's a Honeywell wifi one. Basically on the same level as the Nest.
 
Macdaddy4738 said:
It's a Honeywell wifi one. Basically on the same level as the Nest.
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this does sound it could be t-stat related.

If you're out of ideas, buy yourself a $20 simple old-school analog t-stat and swap it in, just to rule out that fancy one being the culrpit.

These cool new t-stats are really neat and convenient but can make troubleshooting challenging. I've heard tone of stories from friends w/ Nests and similar about having issues that stemmed from them.
 
peewee said:
What kind of tstat do you have? I haven't messed with the new smart tstats but I also haven't seen one that says it waiting for equipment. how does the tstat know it's waiting for equipment? it's an analog signal to the tstat with no return signal to the tstat.
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The waiting for equipment thing is a built in compressor protection on the thermostat. It locks the unit out from restarting earlier than 5 minutes if it has been shut off. This feature has always worked fine for me.

RatLabGuy said:
this does sound it could be t-stat related.

If you're out of ideas, buy yourself a $20 simple old-school analog t-stat and swap it in, just to rule out that fancy one being the culrpit.

These cool new t-stats are really neat and convenient but can make troubleshooting challenging. I've heard tone of stories from friends w/ Nests and similar about having issues that stemmed from them.
Click to expand...

Well that would suck. I think I've had the thing for a little under a year so it may still be under warranty. It's a Honeywell RTH-9580.
 
Your thermostat has probably been hacked.
 
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