Please help me help my tech
First, a timeline:
April 30, 2009: Tech replaces evap. coil because pan has rusted through
June 14, 2009: A/C stops cooling altogether
June 15, 2009: Tech finds it frozen up and 6 lbs (out of ~8 lbs) low on refrigerant. Replaces refrigerant. Can't find a leak
June 16, 2009: Tech comes back because of inadequate cooling. Finds obstruction in filter drier and replaces it, and cleans condenser unit.
June 19, 2009: Tech comes back because of inadequate cooling. No problems found. Adds some refrigerant, but says it didn't really need it.
The A/C hasn't been working correctly since it initially froze up, though it is blowing cold air. It functions fine from about midnight to 10AM and has a return/supply differential of 20 deg F (78-58). Starting at around 10AM it struggles to maintain 80 deg F and the house slowly heats up to 85-87 deg F, peaking in the late afternoon. The return/supply differential shrinks to ~13-14 deg F. It takes until midnight to cool back down to 80. It runs constantly from 10ish until midnight.
It is an older system (16 years) and has been trouble free until the leaking pan issue. I would've had the whole thing replaced, but I am moving within a year and it had been performing wonderfully besides the leak.
The tech is coming back tomorrow to take a look again and I want to be able to ask intelligent questions when he does. Ignoring the potential of having a leak, what could cause this type of performance issue?
My guesses so far:
1) Compressor problems (he said he checked it and it showed signs of age, but it was functioning OK.)
2) Large cold air leak in attic (I looked and didn't find anything).
3) Blower problem
4) Expansion valve problem
5) Improper charging procedure
6) Improperly sized replacement evap. coil
Do all of these make sense for the issues I am having? Can you add any more?
I appreciate any help I get.
Time to call in the pros. This guy is guessing at things.
I would've had the whole thing replaced, but I am moving within a year and it had been performing wonderfully besides the leak.
So you're going to leave the new owner with a cobbed up mess...
How tall are you Private???!!!!
from the ammout of times refrigerant is added sounds like a leak somewhere and needs to be fixed.
if the system was evacuated and charged properly then it should not never need refrigerant added again unless it has a leak
That was my first thought too.
Originally Posted by Gunnery Sergeant Hartman
BINGO! I found your problem..............your tech.
easy!! Purchase a new HVAC system (not from this Co.), the new owner will appreciate this! (it deff wont hurt selling your home)
2. Get a new tech!
Those are your options.
You cant be guessing like your tech... Where did you come up with that list anyway?
Return Air drawing hot air from the attic or garage area?
Perhaps, none of the above...
Originally Posted by MEENag
It sounds like the Return Air is drawing hot air from the attic or garage areas.
When those areas are not so hot it cools better & has close to a normal indoor SA/RA temp-split.
When those areas get hot, bingo it no longer can handle that extra hot-air heatload.
First, check the Condensing Temperature (CT) verses the outdoor Ambient (OAT). The CT spread will increase during the hot part of the afternoon & into the evening.
First, check for temp changes at Return Registers, then just before air enters the blower. Much temp increase during those hot periods? Depends on how the Return Air is ducted as to where you're most likely to find those air leaks. If chamber under the furnace, air could be coming down unsealed walls into the chamber.
Correct any Return Air problems. -Darrell
Last edited by udarrell; 06-29-2009 at 11:58 PM.
When I said "besides the leak", I meant the rusted evaporator coil pan that I had replaced, not the potential refrigerant leak that hadn't happened yet.
Originally Posted by Gunnery Sergeant Hartman
When I decided to replace just the evaporator coil because of the rusted pan and not get a whole new system, my thinking was that my system had performed without flaw for 16 years and that it might well last another 4-5+ years. It wasn't about the money, well partially, but it was more about not wanting to trash a perfectly good system. Whoever buys the house will know the age of the system and will take that into account when making an offer and I won't have a problem making concessions for it. Thanks for making a judgement on my character though.
Where did I come up with that list? I made it up and came here and asked if any of them made sense and if anyone had other ideas. Clearly I'm no HVAC pro.
Please shoot down any of my guesses that don't make sense.
If I thought this process would've been any more than a quick evap. coil swap, then I would've had the system replaced.
The tech is a nice guy and was recommended by several people. He charged me a small amount for his first visit after the evaporator coil replacement and didn't charge anything for the next two visits. He's the owner of a two truck independent business and has probably lost money because of accepting my job. I figure I'll give him another chance tomorrow and then call in someone else if he can't figure it out.
Excellent suggestion. That's the kind of information I was looking for. Thanks.
Twilli says HVAC guys are hard on H/O's. Cause some of them used to be H/O's themselves
No Heat No Cool You need Action Fast
Yes, I'm a s
It appears everyone is avoiding a response to my post explaining why all the symptomatic experience data points to hot air sources entering the Return Air.
Because of when the indoor split is reduced, e.g., when the attic or garage would be hot, it is an easy diagnosis. The indoor temp-split is mainly dependent on indoor Return Air temp & humidity levels.
Additionally what is the humidity levels in your attic or garage.
I have seen & solved this problem many times during my many decades as a Tech & Contractor. Smaller Return Air leaks are usually overlooked leading to costly inefficient performance.
It is possible you might learn a little HVAC by going to my Internet pages, for this month of June alone hits appear to be going over 80,000, & the HVAC pages lead all other pages by a wide margin for number of hits.
Do you want to solve the problem or just talk about it?
If you don't want to respond to my analysis, perhaps I should quit trying to help anyone solve their air conditioning problems.
Why should I spend any time & effort in an attempt to help anyone solve their problem on this forum, when I'm ignored & when there is no feed-back?
I guess I'm a spoiled child, I want a two-way communication, or it's so-long it's been good to know you.
You might spend a fortune on new ultra high efficiency equipment & end up with hot-air, pardon the pun. - Darrell
Last edited by udarrell; 06-30-2009 at 07:54 AM.
Reason: Sorry, I hit Enter instead of Shift Key, so title, post not finished