Janitrol Central Air unit evaporator freezing

[Qball]

I just replaced the condensor fan in the unit. A few days later, after some decent use, I found that next to no air was coming through the vents. Upon investigation I discovered that the evaporator was iced up and blocking nearly all air flow. This has never happened in the 4.5 years I've lived in this house. Can anyone lend some insight as to why this would happen now? It's hasn't been extremly hot (I live in suburban Chicago)and the humidity is on par with this time of year.

Thanks, Mike

[Samurai Appliance Repair Man]

Well, it has nothing to do with your replacing the condenser fan, purely a coincidence.

[Qball]

I assumed that it had nothing to do with the fan replacement.  But you know what can happen when people ASSume things, right? I just thought it odd that it happen to ice up shortly after. 

[exsearsguy]

Filter and evaporator clean? Are you running it at night when it gets cool outside?

[Qball]

I looked at the filter and it looked to be time for a change and yes, I ran it at night when it was cooler

[exsearsguy]

WELL, IF IT GOT MUCH BELOW 75 DEGREES, THEN THE PRESSURES IN THE CONDENSER CAN DROP TO LOW,DROPPING THE PRESSURES(and the temps) BELOW THE FREEZING LEVEL IN THE EVAPORATOR. THEN YOU GET A FROZEN EVAPORATOR AT NIGHT!!!!

[Qball]

Alright, alright I learned my lesson. Sheesh, you don't have to yell at me!

[exsearsguy]

Sorry I yelled at you. But anyways, try waiting till the nights get warmer and see if you still have the problem. I think there is a good chance that it will fix itself. I know that the last few days down here in Tennessee the nights have been quite cool. Just right to cause your problem( even had a call on it yesterday).

[Qball]

No worries, ex. Besides in a week from this Monday my wife and I close on a new house and we wont have to worry too much about this old unit. I just wanted to be sure that I wasn't sticking the people buying our house with a bum A/C system.

[Guest ahammer48]

Hello

Has the freeze up problem gone away?? I hope its coincidence, but it could be that during the condenser fan mtr change out, U may have started a freon leak. U may have disturbed a bad weld joint or possibly one of the screws U removed to take the top of the condenser off has now punctured the coil when U re-installed it. Some quick checks:

I'm ass-uming U have run the unit after the mtr change out. Shut the power off 2 the condenser section and remove the top again carefully. Check all around the condenser looking 4 any oily/dirt spots. Pay particular attention to the areas where the screws go back in. U can make a bubble detector solution by mixing dish washing detergent with water. Use more detergent then water to make it so its not to runny. Use a paint brush and paint any suspect areas.

Even if U don't C any oily areas paint the pipe connections to the compressor-any screw areas that are close to the coil-where the pipes exit the condenser. It may not be a big leak that makes a lot of bubbles. It could be a squeaker and U might just C a little foaming. B patient.

If U have a set of service thermometers, stick 1 in the return air to the evaporator section (the furance section) & 1 in the supply air (cold air to the house). Do it as close to the cooling coil as U can. Your looking 4 a 18-22 degree spread between air in and air out. Example: return air is 74 degrees and supply air is 54 degress= 20 degree spread. If the sprerad is low (<=14 degress) U may B low on charge.

[Qball]

Thanks for the tips! I have run the unit since it froze up. It seems to be running well. No more problems. Besides in a week I'm out of here and into a new house. We're supplying a home warranty to our buyers so I'm not too concerned. If there's a problem, the warranty will cover it.

[jehiatt]

If it was freezing up it was probably low on freon and costing you a small fortune to boot. There is a fine line to charging a unit to get the maximum cooling for the current being drawn at the time.