3 ton, 1200 cfm..

[rpope904]

I posted here a couple of days ago, due to my coil freezing over.. I had the repair tech back out, I am in test and balance so my repair ability is limited.. He checked the freon, said it was good, and added alittle more.. Well, once the sun went down, so did the coil temp. I had strapped my temp probe on it and closed the unit up. I got my flow hood out, and checked the return, which is right off the wall which the unit is on, was only pulling 750 cfm, checked 2 registers, one was giving 160 cfm, another 55 cfm, I pulled the coil cover off, to bypass the return and checked them again the first one was now 250 cfm, the other was 105 cfm.. Almost 100% improvement. I know that 1200 cfm is just an average, not all will get it, but 750 is way too low. I called the guy back out, he took the coils and pressure washed them, I checked it when I got home, and it's doing the same. What's my next step? Thanks!

[Mustang894me]

so many Questions.. OD temp? did he check a coil for build up? filter ok? why did he add Refrigerant? was it low? did he do a leak check? hows the OD coil look? if the freon was ok why did he add more? did he tell you the superheat or sub cooling? what was the pressures what is the wet bulb god i can keep going.

[rpope904]

OD temp was around 85, the condenser is brand new, installed 3 weeks ago, filter was replaced a week ago, No idea why he added any, he said it was fine, I put my gauges on it to check it as well afterward, and it was fine.. So it apparently wasn't when he checked it.. He didn't do a pressure test, I will do that in a few myself with my shortridge module.

[Mr Bill]

I guess that's no different than checking your blood pressure after the surgeon has done heart surgery. :LOL:

[beenthere]

OD temp was around 85, the condenser is brand new, installed 3 weeks ago, filter was replaced a week ago, No idea why he added any, he said it was fine, I put my gauges on it to check it as well afterward, and it was fine.. So it apparently wasn't when he checked it.. He didn't do a pressure test, I will do that in a few myself with my shortridge module.


Pressure was fine? What pressure is fine for 85 outdoor temp. I don't know.
I'd have to take temp readings. To find SH, and SC.

Your a T&B guy. Check how many CFM your actually moving through your system.

Do you have a manometer? If so, check your systems TESP.


Is your system a mismatched system?

[Mustang894me]

im taking it he used a 410a system... did he replace the indoor coil? are they compatible? did he do a static pressure before and after filter before and after coil. you sure the furnace is able to push there right air across the coil? if you mismatch systems put a new coil on a old furnace they might not be able to move the right air..

[rpope904]

It's pulling 750 CFM through the return, one register.. No outside air, and I will check the T/ESP in a sec on it

[rpope904]

He didn't replace the ID coil, he 'cleaned' it.. I haven't opened it back up yet, but i'd be willing to bet that it's still restricted. Perhaps I should just bite the bullet and replace it. (assuming the pressure isn't restricting it)

[beenthere]

You might be pulling 750 through that return grille.
But, with return leakage, you may be moving more air then you think.

You said the outdoor unit is only 3 weeks old. Is the indoor coil still the old coil?

[Mustang894me]

He didn't replace the ID coil, he 'cleaned' it.. I haven't opened it back up yet, but i'd be willing to bet that it's still restricted. Perhaps I should just bite the bullet and replace it. (assuming the pressure isn't restricting it)

holy hell .... how old is the indoor coil? did he use a 22 on 410a or did he use a new 22 on old 22 ... wow this seem like a botched job... is it a txv ... fixed orriface ...

[rpope904]

It's the original system, so 15 years old. He is meeting me and the flowhood tomorrow afternoon, It is def. a botched job, he is a friend of the person we're buying the house from, I am gonna have the ID coil replaced.. Everything seems to point to it being restrictive

[Mustang894me]

is the OD system a 410? or 22

[beenthere]

So what are the chances that the old outdoor unit was a 2.5 ton, and they stuck a 3 ton in.

[rpope904]

its a 22

[rpope904]

Probably a good chance, billy bob's AC work at it's finest. ;) before we moved in, the old OD unit was stolen, so I don't know what was there

[Mustang894me]

whats model # or new unit? do you know coil size? or model # of coil? ... opps lol been ther just asked that

[rpope904]

ID Model is carrier # FA4ANF936000ABBA
OD Model is Ecotemp # WCH3362GKA1

[Mustang894me]

hate too say it but might want to rip out both and start fresh... J manual with a 410a system maybe BB ac will work something out with you. remember be nice if you go at him in a pissed off mood you wont get much but an excuse. if he cant figure it out look into another company

[beenthere]

The indoor was probably set up for a 2.5 ton condenser.

[Mustang894me]

both 3 tons theres a block some where .. you said pressures were fine what were they .. what was you superheat? delta T ? therehas got to be a big air restriction the furnace what s the indoor speed on cooling ... alot of things still to check .. cant go into much more on diong here more post an you can apply for pro membership

[Mr Bill]

Sounds like something fishy going on here.
http://i99.photobucket.com/albums/l286/mrbillpro/fishy.gif

[Mustang894me]

whats your supply cfm?

[udarrell]

If the A-Coil was loaded with lint, then the curve in the blower wheel blades will be filled with lint too, if it is, it can't move much air even through 'now' the A-Coil is clean.

Check out the blower motor & run cap -if it has one. Do what it takes to get the 1200-CFM of tested delivered airflow; then recheck the charge & everything else!

If it's an Oil furnace, on most, the A-Coil should be installed at least 6" above the furnace - or there will usually be high back-pressure & very low airflow.

Also, make sure all the ducts are well sealed, including the entire Return duct system.

Others here have made excellent suggestions for you to follow. :payattention: - Darrell

[Mustang894me]

any word on how the meeting went today w/ the flow hood?

[rpope904]

Yep, no show. ;P I talked to the person I am buying the house from, who is his friend and told them I am tired of dealing with it, to just go ahead and install a new 3.5 ton air handler..

[dash]

So if the original ODU was a 2.5 ton ,now you'll be oversized and the duct system will be undersized . You need some Pro help here.

[Mustang894me]

Yep, no show. ;P I talked to the person I am buying the house from, who is his friend and told them I am tired of dealing with it, to just go ahead and install a new 3.5 ton air handler..

wow that sucks man sorry that he no showed ... hopefully the same guy is not installing the air handler.

[JWB]

I hope he didn't PRESSURE wash it.