Pipe from compressor frozen

[bicker]

Can someone knowledgeable about residential hvac please confirm an assumption? Our a/c was pretty ineffective for the last day or so. On closer inspection, I see that the pipe from the compressor outside into the house seems frozen or that it was frozen and the icing is melting a bit.

Is this "normal", in that it happens sometimes, and the "right" answer is to just shut the system down for a little while?

Another question: I assume that if you have a whole-home humidifier, that you're supposed to turn it completely OFF before you turn the hvac system to a/c. Is that right? (And by extension, forgetting to do so is a likely cause of that pipe freezing up.)

 

[janey99]

We had this happen a couple of years ago. It turned out the drain lines for condensation were blocked, which was leading the outside unit to kick on repeatedly, until the fuse blew on the automatic "cycle off" part and the thing just kept running until everything started freezing up.

The HVAC guys opened up our outside unit and you could see where the fuse was actually burned, and it needed some type of new swtch.

Probably not the most scientific explanation, but maybe somewhere to start.

Jane

 

[3boymthr]

DH is an HVAC. I see you also live in MA. One thing to keep in mind, you need to shut the unit off when the outside temp is lower than the temp that you have it set at. With lows in the 50's over night you're damaging the system if have it set at say 70 and you are running it overnight. DH is always talking about this happening. HTH

 

[bicker]

That's a big problem around here. We live right up against the Interstate, so keeping the windows open at night is simply not an option.

Well, thanks to our service contract, they're sending someone right out. He should be here in about 10 minutes. I'll know for sure then.

 

[rlduvall]

This has happened to us many times, unfortunately. In our situation, it has usually been because there is a small freon leak somewhere and our unit is low on freon.

Good luck.

 

[jocon]

We had this same thing happen. It usually means that air flow is restricted to the air handler. We found a hidden filter that must never have been replaced and the problem appears to be solved. It could also mean the coolant level is too high or too low (leak).

 

[ToyStory Fan]

First I'd start by checking the little things...
turn the units off as they have been strained due to the frozen pipes

then I would check to see that the filters have been replaced...if your unit doubles as a forced hot air or hydro air heat unit, the filters will likely be dirty/clogged from the winter season.

I would also check your drip pan that the airhandler unit rests in...this is a shallow (1-2" aluminum/sheet metal pan that catches any excess water) - remember the a/c is removing humidity from the air...if the handler is blocked it will have massive condensation build up and could also trip your drainage sensor.

If that pan is filled you will need to get a wet/dry vac and clear the water from it.

Once you've checked all that and the unit has had a fair amount of time to "defrost" and cool down I would turn it back on and wait to see if there is any change/improvement...if not then I suggest calling in an HVAC expert as you may have a leak or low freon situatiuon that needs to be addressed by a pro.

Good luck.

 

[bicker]

So the culprit appears to be the rehab we just went through. We had tons of water damage this winter and the crew was in here over the last two weeks doing all the repairs and such. Evidently, that kicked up a lot of dust and debris, which clogged the filter. That, in turn, backed up the system, freezing the coil. The tech ran the heat for twenty minutes, the ice melted, and now the system is working fine. He's checking the levels and such, as he normally does, but nothing seems awry.

 

[Janet Hill]

DH is an HVAC. I see you also live in MA. One thing to keep in mind, you need to shut the unit off when the outside temp is lower than the temp that you have it set at. With lows in the 50's over night you're damaging the system if have it set at say 70 and you are running it overnight. DH is always talking about this happening. HTH

Does this mean then that if you lower your thermostat to 45 it will be ok?