I have a 1998 4-ton Carrier heatpump. I have been replacing the blower fan motor control module about every 1.5 years or less.
It has happened so often, that I bought an extra "emergency" one when I replaced the last one. I just used the extra one on hand as the last one that I put in only lasted 8 months.
These things are about $200 bucks each. They have a one-year warranty IF the dealer installs them, but no warranty if I install them. Since I live in the boonies, and it's difficult to get the dealer out in a timely manner, I DIYed the last 3.
What gives?
Thanks.
Mike

 

It's hard to tell. Could it be that you've got something funky going on with your electric. Being out in the "boonies" you may have fluctuating voltages "surges/drops" that may be shortening the life of these modules. You could try adding a surge protector to the circuit and that may help if that's even the problem.

 

One of the service techs admitted to me that Carrier was having a LOT of problems with these modules (which, I understand, got him chewed out by his boss). Must be a design flaw.
I installed a "whole house" surge protector for my entire electrical panel a few years ago (and I have another for my computer), so I'm not sure that would help.
I know very little about HVAC. Looks like I'll just have to live with it until I replace the unit, unless Carrier improves the replacement part. I've had nothing but problems with this system since I bought it. I have over $8,000 in it now, and it still isn't working just right. The dealer has been "far less than helpful", but Carrier itself has replaced the compressor (NOT including labor) and a couple of these modules.
My first and last Carrier and my last business with the dealer, the largest in this area. In the first place, they installed a 4-ton, which I've since learned is way too large for my house. I have had three other dealers AND a Carrier rep out here who have told me that they shouldn't have installed more than a 3-ton unit.
Believe me, as a real estate broker, I have cost that dealer far, far more than $8,000 in referral business since 1998. I live and do business by the Golden Rule, and I am definitely doing unto others as they have done unto me...long, deep and continuously. LOL
Thanks.
Mike

 

I've not been a big fan of Carrier residential stuff for a long time. The last one I put in I tried to talk the lady out of but she insisted since her old one lasted 25 years. She's not had any mechanical problems out of it but after the install she couldn't stand the noisy scroll so I installed a sound blanket to deaden it.

 

Im like Matt ,I dont care for the heatpump you have there now but oh well.
MIKE you say boonies , surge protector and new compressor. I dont think that is what is doing it to you here . So the cost is small "maybe $10.00" and If you can buy at Grainger or Johnstone supply go and get a #ICM2O3B or other make timer. Its a time delay on start up after a power outage."Time delay on break". You can put it inside or at the ouside unit. You just wire it in on the tstat wires going to the compressor. This way if the lights just flick on and offthe compressor cant come back on right away. Just think that poor compressor is trying to start against 250 to 300psi and it cant for a while so it just rides on the klixon . Its like that here im in the city and I have never had as "BAD" electric as we have here. I even have time delays on my fridge and deep freeze.I think the techs down here just live on compressor replacement caused by the power company. I do have a square D surge protector in the panel and one on my PC here .You do need them when spikecomes in. I also found that Im better off with a small cheap battery back up on the PC. This one will hold me for 5 min. Some times the lights go on and off so fast I think they did but didnt see them . BUT ill here the battery back up kick in to cover it and then turn back off.
As I said Mike the cost is low give it a try for sure.We have been putting them on A/C units for years

ED

 

being oversized will cause the indoor fan control to operate A LOT more often, wearing it out quicker.

are we referring to the control board in the AHU that the low voltage wires hook into? does the fuse blow?

what exactly does it do when it fails?

being in the boonies suggests a possible voltage drop....which would cause your problem, both the boards and the compressor

my 2 cents

 

Ed, thank you. There already is a 5-minute time delay on the system for power outages, mode changes, etc.
hvac4u, the dealer supposedly "slowed the indoor fan speed down to low". At least, that's what they told me.
On my on, I bypassed the downstairs zone control damper motor and set that damper wide open. Only the upstairs zone control opens and closes. This has helped the operation and temperature balance of the system. The son of the dealer, supposedly their top tech, said that he didn't even know that you could do that with the dampers or how to do it (I showed him how.)
It's not the control board and it doesn't trip the breakers. There is an indoor fan control module mounted on the bottom of the indoor fan motor. It just stops working when it fails, and of course, the indoor fan stops circulating air, and everything frosts up. When my heatpump stops heating or cooling, and I don't feel any forced air from the vents, I lift the top of the outdoor unit to see if the fan is on. If it isn't, I know that it's yet another motor control module failure.
I check the plug-in contacts with an ohm meter to be certain that the one that I remove has failed (no continuity), and I check the motor (always OK).
I guess that I'm just going to live with it a while until I bite the bullet and replace it.
Thank you everyone for you insight. I know zilch about HVAC, and before I replace it, I'm coming back here for your opinions on the best to get.
Mike

 

If you have the ability could you possibly relocate the fan board so it's not on the blower housing? I've seen where the vibrations of the fan housing will cause the solder joints on the circuit board to crack.

I still think it's bad voltage. If you have a multi-meter check the voltages at differant times of the day and see if it's normal.

 

There is no visible evidence of any solder or other damage to the control module. They look "brand new" even after they fail.
I will follow your advice about checking the voltage periodically. I don't know what I can do about it, if I find major fluctuation, but I'll check it out.
Thanks.
Mike

 

is this a variable speed unit? sounds like a package unit also. what is the make and model? i can look up the part that is failing and see if there are any bulletins on it

 

Sorry you are having so many problems with this air handler. One thing you can check is to make sure the wires going to the module have a drip loop. There was a service bullentin issued a few years back on this. In some cases the motor had to be rotated in order to accomidate this. The wires going to the module need to dip below where they plug into the motor and then back up. This will allow any moisture that forms on the wires to drip off instead of running inside the module, which can short the modules. Another way of looking at it, is that it should form some sort of p-trap, like under a sink. Hope this helps.

 

No offeense to any of the other replies, except nominal's (His is the only one that is in line with your problem). The ECM motors (any brand) are very susceptible to moisture. Since your motor is after the indoor coil (on most heat pumps), it can get moisture in it quite easily if...
Indoor coils are not clean
If you are using a Electrostatic filter. These are death to most systems, but especially heat pumps. Their pressure drop is too high and can cause the fan to pull moisture off the coil. Accentuated even more if you have a Hz. application. Use a good pleated filter instead. Don't pay more than $10.00 for a pleated. Anything more is just hype, and more air restiction. Do Not use fiberglass! They let as much dirt and dust through as they catch!
Make sure your condensate drain line is properly trapped. A good rule of thumb is 1" per ton, and has at least 1/4" per foot slant (of fall)
Make sure your return air is large enough. Again, a good rule of thumb is @ "least" 1 sf per ton. This seems to be one of the most common oversites.
Make sure FCU is level or @ least (if not) that is unlevel towards the drain.
Heat pumps are great, and now days, may possibly be the the most efficient heat source there is. In regards to DX systems that is. The largest problem is finding a company that has techs that actually (and really) know how to work on them. Properly!
I hope this help you solve your problem. Good luck