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Evaporator Coil dripping


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I have a 2 ton A/C unit (r22) which runs to a closet air handler. I had been having to recharge the system about once or twice per season. Using a freon detector I could tell that the evaporator coil was leaking and decided that I didnt want to leave a leaky coil for the next owner (I am moving soon). My old coil, which worked fine overall was a single flat piece angled from down in front to up in back. The filter is mounted below and the fan is mounted above and pulls air from below, through the coil and out to the house. I bought a new coil, same height and width (mostly) but a bit thicker. Piston is .059, which I believe to be correct for my R22 unit.

The placement of the coil was fairly easy but the install was a bear, mainly due to difficult positioning of the output. Eventually it sealed up, held a nice vacuum and the was filled with R22. The system blows cold air now but as soon as the blower turns off, there is so much water in the fins of the evaporator that it drips down in to the filter. Not just a little either. Worse than that, I can tell there is so much water inside the air handler that the wires inside are wet.

The day we put it in it was very humid. But this seems excessive. I don't ever remember seeing much water on the previous coil and I never had water on the filter.

I'm at a loss as to why the new coil is acting like this. Can anybody give me an idea what is going on?

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I'll assume that new coil is an exact replacement coil, has the same exact slant as the old one and is not an 'R410A only' coil. I'd wait until humidity levels in the house were 'steady-state' before judging it. You might also check if the thermostat you have installed has a dehumidification setting which slows down the blower to drop evaporator temps for better dehumidification performance. Finally, the refrigerant charge may not be correct. Sometimes charge levels favor the formation of a little ice when it's calling for cool but as soon as the call is satisfied it melts almost instantly and you have a small torrent of condensation.

Marc

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Thanks for the response.

"Exact"? The system is very old. I'm not sure if the evaporator coil is part of the tempstar cooling unit or the fedders heat/air handler unit. Whatever the case I couldn't find an exact match. Old coil was 16x17x2 while the new one is 16x16x2.5. The piston on the new is .059 which I believe is correct....but I'm basing it on a chart I ran across online. Could that be wrong? It's a 2 ton unit.

The new fits nicely where the old one sat...gross size is essentially the same...had to put a couple holes in the frame to screw it in to existing holes. It also sits at exactly the same angle. I'm assuming that's ok.

I've been leaving the fan on all the time which seems to keep everything fairly dry. But if I only run the fan when the ac starts, then when it shuts down it still drips a lot of water....pools in the pleats of the filter then drips thru.

Michael

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Thanks for the response.

"Exact"? The system is very old. I'm not sure if the evaporator coil is part of the tempstar cooling unit or the fedders heat/air handler unit. Whatever the case I couldn't find an exact match. Old coil was 16x17x2 while the new one is 16x16x2.5. The piston on the new is .059 which I believe is correct....but I'm basing it on a chart I ran across online. Could that be wrong? It's a 2 ton unit.

The new fits nicely where the old one sat...gross size is essentially the same...had to put a couple holes in the frame to screw it in to existing holes. It also sits at exactly the same angle. I'm assuming that's ok.

I've been leaving the fan on all the time which seems to keep everything fairly dry. But if I only run the fan when the ac starts, then when it shuts down it still drips a lot of water....pools in the pleats of the filter then drips thru.

Michael

Then there's the added possibility that the coil and/or piston isn't correct for the condenser unit installed and for the characteristics of the blower. Blowers that usually accompany gas furnaces don't move as much air as the 240V ones that accompany electric heaters. That could be a factor.

If the dripping is more than you're willing to live with and you're going to do this yourself, you might try a 0.053 piston if the head pressure stays within bounds.

Better advice is to get more technical expertise onsite. Your situation sounds tricky but a resourceful AC tech should be able to solve it.

Just on the off chance: Does the exiting air flow from the condenser go straight up or is it somewhat at an angle to vertical?

Marc

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Then there's the added possibility that the coil and/or piston isn't correct for the condenser unit installed and for the characteristics of the blower. Blowers that usually accompany gas furnaces don't move as much air as the 240V ones that accompany electric heaters. That could be a factor.

If the dripping is more than you're willing to live with and you're going to do this yourself, you might try a 0.053 piston if the head pressure stays within bounds.

Better advice is to get more technical expertise onsite. Your situation sounds tricky but a resourceful AC tech should be able to solve it.

Just on the off chance: Does the exiting air flow from the condenser go straight up or is it somewhat at an angle to vertical?

Marc

I can't possibly sell this house if it's leaking water like this... even if they didnt notice..

I think I'll try the different piston size. I think it's fairly easy to switch out. And I certainly don't want to take the whole coil back out.

The system is entirely vertical.. air in the bottom and straight out the top in to the ceiling. It's a wall mounted, all electric closet system. And it used to work pretty well until I decided to fix the leak....

Thanks again for your responses and your time. If that doesn't help I'll call a pro out.

Michael

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