think i might have too much refrigerant in my York heat pump. There are two copper lines leaving the outdoor coils, going to the basement unit. The large line is freezing up. Vent temp is about 60. Ambient temp is about 75.
Type of HVAC: Air Conditioner
guage on low side reads about 20 when unit is on
All work to be done by licensed professional. WE KEEP GOING UNTIL YOU HAVE THE INFORMATION YOU NEED, I come and go. This is step ONE.
If it has been working earlier and is frosting the suction line now, then the problem is not enough air moving through the basement unit.
A dirty air filter will cause the problem
filter is clean
Any thing that blocks the air flow will cause the problem
had a technition do a tune up today. Think he might have been a jack-leg. Added refrigerant, now it is doing this
Too much refrigerant will not cause the icing, it will actually cause the coil to run warmer. too much refrigerant raises the pressure in the system, the temperature rises with the pressure
would too much refrigerant do this, or would too little? Low side reads about 20 on guages and vent temp is 60. temp was about 48 before he came
He probably added refrigerant because the suction pressure was lower than it should be
should it be this low? It a dual fuel heat pump. about 4 years old
The combination of not enough air flow and a full charge of refrigerant will cause the suction line to ice
Ive been at this for fifty one years so far
and I'm guessing that the suction line is the larger of the two?
We can figure this out one step at a time
I believe whatb you tell me. That's why i'm asking. You are the pro.
Yes suction line is the larger line
That's why I'm asking. I believe you are the pro
ok, and too much refrigerant wouldn't cause it to freeze? it was running better before he added it.
Let me ask a series of questions and stay on that trial for about five minutes and I will know whats wrong with it
What refrigerant does the system use? R-22 should run 60 psig suction pressure
R 410a the newest refrigerant should run 100 psig suction pressure
pressure is now 20
the 20 psig suction pressure read would be a system so low on refrigerant or so iced solid that you would get no cooling at all. Accordingly I suspect the suction pressure reading was taken improperly
Tell me if there is any air flowing out of the cold air vents
ok. I took it at the inlet on the back of the outdoor coils
yes air is flowing
Will the air flow lift a cleanex off of the supply air grill?
at least when it first comes on. I just turned it back on. Will see if the air flow lessens in a few min.s
Either the unit is not moving nearly enough air, or your gage is broken
or you are not operating the gage manifold correctly
just hypothetically...what would happen if he overcharged it.
with suction pressure at 20 psig and plenty of air flow across the coil, the suction line would be warm
unit ran fine before he came. Just wanted a tune up!
If he over charged it, and there was plenty of air flow across the coil and the room was at 70F a unit using R22 would run suction pressure over 60 psig into the 70 psig range
If the unit is running R410a and its over charged and is getting good air flow the suction pressure will run over 105 to 110 PSIG.
ok. think I should just get another technition to come out, now?
it is definately r 22
It would only run 20 psig if it were mostly out of refrigerant or there was very little air flow across the indoor coil...
ok. Then maybe he let refrigerant escape, instead of add too much
What caused you to call for service in the first place
unit was installed about 4 yars ago and haven't had a tune up. Just started getting hot, here in Kentucky, and thought I was overdue for a tune up
you said earlier that the cold air supply was 48F before he came, that would have cooled the house off very very quickly.
If the house was not getting cool with 48F supply air temperature, then there was simply not enough air. due to a blocked air duct or dirty cooling coil
I got my HVAC universal certification, back in 1995, but never ended up working as a technition, so I feel safer hiring someone to do the work...but still know enough to be dangerous!
When he added refrigerant, with not enough air blowing through the coil that would have caused the suction line to ice
yes, it worked fine before he came
Why did you call him?
The supply air temperature in cooling mode should run 15 to 20F cooler than the room temperature.
like I said, unit was new 4 years ago, and has never had a tune up. Just thought it would be good preventative maintanence
So on a 70F room. the supply air should run 48 or 50F.
that sounds right to me
If the room was below 70F, and... it was also not hot outside, say it was only 75 outside, then the coil would run below freezing and ice the suction line... it would have been running the AC under conditions it was not designed to run at.
So the coil runs below freezing, THEN if you add just bit too much refrigerant, it will ice the coil and it will ice the suction line
we try to keep the thermostat at about 75. It got up close to 90 today
If the supply air was at 48F with the room at 75F, then the system is not getting quite enough air flow, the suction pressure would have been low, but not at 20 psig. more like maybe 50 psig
then the repair man would have added a few ounces of refrigerant, and since the system is running short of air, it would have iced the suction line
You are the man. Thank you so much for the infomation. Think you have answered my question.
Especially if he was out earlier in the day before it got to 90F outside
I also think I might need a larger or an additional return line
house is 2200 square feet and only one return.
If suction line fits the outside unit it is the right size
its not likely undersized or the fittings wouldnt be compatible
I mean return duct
Too small a return air duct is a very common problem
and will cause the problems you are having
thank you. So glad you were up tonight. Think you solved it
it would be smart to add another return duct or increase it in size, and to add a supply air duct and an extra supply air grill
You can continue on through the repairs for days or even months after you click the accept button
yes the one I have now is only 14x30. I did at least insist on all metal ducts
If the ducts are insulated on the inside, the duct liner can come loose and restrict the air flow.
Retired HVAC/ Electrical & Boiler contractor. Industrial
thanks for you help. The jack-leg I had come out the first time had let refrigerant escape, instead of addong it. I had to have @ 4.5 lbs added and am in the process of having another return duct and grill added. Thanks again
Hello again, it sounds like you might have gotten a good man out there, let me know how it goes. Thanks for accepting.Phil