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BlueBSH 08-29-2011 10:03 AM

AC starting to freeze?
 
AC has worked fine for the 2 yrs I have owned the house, last month had a cap go bad, replaced it, had them also check the refreigerant levels, they added 1.5lbs I think it was, AC was 5yrs old, prev owners apparently never had it serviced... worked until last night the furnace felt like there was little air coming out of the vents, and it was running forever and temp wasn't dropping much... went downstairs to the furance the thing sounded different, almost like the blower wasn't running at high speed, sounded more like low speed... (this is not a var-speed furnace, heat and cool are set to high speed, motor has 3 settings possible)

well shut it off for a bit, completely powered it down let it sit brought it back up, AC compressor unit came on fine, was running normal, went down to the furnace still sounded odd, turned it off, pulled the filter, wasn't bad, but was time to clean it anyways... (this is a washable filter since they dont make disposable ones in my size without special orders)

washed the filter, let it complely dry, put it back turned it on again, same thing, sounded like it was not running at full speed... then noticed that smaller line (liquid line?) was freezing cold, I thought that was supose to be the warm one? but where the connection is I think that is the orface? was covered in ice, this has never happened before...

I can't see into my A coil completely without opening the box up, but where the humdifier is mounted on it, when I take it's water pad out I can see the fins some of the A coil, and ontop at least it didn't look to be frozen over, at least not yet, not sure what the underside looked like..

let it sit idle for a while, then noticed the ice was melting and a LOT of water ran out the drain line probably a constant stream for 5 to 10 minutes was't keeping track of time too well..


what is causing this? In theory the filter is clean, the outside unit was serviced and refrig was checked and topped off....

could the high speed on the blower of gone bad and it is reverting to a lower speed which isnt getting enough warm air over the A coil to keep it from freezing?

JJboy 08-29-2011 10:29 AM

Set your thermostat to fan on....if the speed is still running slow, the motor/capacitor is bad. If the motor started running in high speed. You have to check the controller board......model and serial ????/

BlueBSH 08-29-2011 10:35 AM

Quote:

Originally Posted by JJboy (Post 717208)
Set your thermostat to fan on....if the speed is still running slow, the motor/capacitor is bad. If the motor started running in high speed. You have to check the controller board......model and serial ????/

I'll have to check the speed again when I get home, it sat idle all night just to make sure if it was iced over its all melted before I try again

Aire-flo
AF92MPE125U5B

is the furnace model

BlueBSH 08-29-2011 12:07 PM

turned it back on today and the blower sounds like its running at full speed right now, checked the temps at the return and after the A coil also

Return temp:70 degrees
Above Coil: 36.5 degrees
Total trop 33.5 degrees

now I'm lost, what would of caused this? anything else to look for?

JJboy 08-29-2011 12:28 PM

Low refrigerant, bad TXV....etc......needs to hook up the gauge and check pressures


Return temp 70F??????? we are talking about your home or your refrigerator LOL

BlueBSH 08-29-2011 12:31 PM

Quote:

Originally Posted by JJboy (Post 717260)
Low refrigerant, bad TXV....etc......needs to hook up the gauge and check pressures

alright, thanks will have to get a pro out then, I don't have a set of gauges, nor do I like working with refrigerant :laughing:

BlueBSH 08-29-2011 01:03 PM

Quote:

Originally Posted by JJboy (Post 717260)
Low refrigerant, bad TXV....etc......needs to hook up the gauge and check pressures


Return temp 70F??????? we are talking about your home or your refrigerator LOL

whats wrong with the return temp being 70 degrees? that's the ambient temp in the house when I started the system back up, and the temp that I pulled when I checked with a thermometer at the return duct filter

right above the furnace A coild it was 36.5 degrees

by the time it got to the other end of the house the air temp coming out of the vents was only 60 degrees

JJboy 08-29-2011 01:31 PM

70 is cold....what is the outside temp?

anyway temp above the coil should be around 55-58

BlueBSH 08-29-2011 01:38 PM

Quote:

Originally Posted by JJboy (Post 717292)
70 is cold....what is the outside temp?

anyway temp above the coil should be around 55-58

well today the outside temp when I checked this unit was only 68, so 70 isn't too much of a shock for inside, yesterday the outside temp was 87 and inside temp was 78. and very humid

NitroNate 08-29-2011 01:54 PM

if air flow is ok, most likely it's a bad txv or evap. coil. if it's low on refrigerant, the coil is probably shot and is starting to leak. the leak could be anywhere, but evap. coil is the first place to start.

BlueBSH 08-29-2011 08:25 PM

pro came out and looked it over, checked all the temps, levels, etc said it looks perfect...

now I am really lost on why it was acting wierd yesterday and started to freeze up

JJboy 08-29-2011 08:41 PM

I think you set your thermostat to 60F when outside temp was 68F.......try to leave thermostat at 72-75F

BlueBSH 08-29-2011 09:55 PM

Quote:

Originally Posted by JJboy (Post 717577)
I think you set your thermostat to 60F when outside temp was 68F.......try to leave thermostat at 72-75F

*lol* nope didn't do that, its a programmed themostat and we never override it... its set to 72 for cool and 68 for heat 7 days a week, and it was almost 90 outside when it froze ;)

BlueBSH 08-30-2011 06:52 PM

well happened again......

its 88 degrees outside, house is 80 degees inside, had it off all morning since it was so cool in the morning, after 2 hours the temp dropped a whole 1 degree... checked it and its starting to freeze again......


so airflow is fine.... clean filter
refrigerant is ok
outside unit is running fine apparently according to the hvac tech...

now im just lost...

worked fine for 2yrs at least and fine until this week

beenthere 08-30-2011 07:10 PM

Does your system have a TXV?

Did the tech only look at pressures, or did he also check SH and SC.


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