Help identify small water leak coming from A/C Coil in utility closet

Old 06-20-09, 01:19 PM
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Help identify small water leak coming from A/C Coil in utility closet

I don't know much about Hvac, but my limited knowledge I am familiar with the outside condenser and the inside ( furnace unit, coil ..etc)
The thermostat is set on Cool (off course) ans we run the fan on 'ON' all the time so the air can circulate in the house.
I noticed there was a small water leak, they are small drops of water forming right at the bottom of the coil which sits on top of the Furnace Unit. The coil box is what sits on top of the furnace unit, right? unless it is called something else, so please forgive me.

These drops of water form at the bottom of this coil box and right above it I see the copper pipes that go to the Condensor outside. These pipes ( one copper and the other black) do sweat a little right where they connect to the coil box, bit it is not that bad.
The other drops of water at bottom of coil they form after a while either after the fan has been running for a while or while the A/C (cool) is ON.

Does anyone know why these drains of water form or if this is a serious problem?

I had the water drain hole ( with the hose coming from the A/C) somewhat sealed with Duc Tape because we has a mouse every once in a while come from that hole. ( all hvac/furnace/water heater are in the basement so that you know).

I wonder if sealing that hole was a bad mistake because this may have cause the hose not to drain properly and the water was escaping from other areas.

Should I keep the water drain hole open for air to circulate and so the drain hose drain water properly?

Sorry , I am throwing a lot here, but I just water to know two things:
1. what could be causing the water drops leaking from the side of coil box?
2. Should the drain hole in the ground stay open all the time(this is where the water hoze is inserted)?

Thank you all so much for any info I get, I really reall appreciate it.

Old 06-20-09, 01:25 PM
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Yes..the drain needs to be open all the time...put some heavy metal mesh (hardware cloth) over it if you have a mouse issue.

If you sealed the pipe, the water (condensate) formed by the A/C removing moisture from the air has no place to go.

Without pictures its a little hard to imagine exactly what you have.
Old 06-20-09, 01:28 PM
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this could be a few things your drain pan could be rusted and be leaking that is in the coil above your furnace you could have a blocked drain line that hooks up to your drainpan above your furnace you could have a freon or airflow problem which causes ice and if you plugged the drainline outside that also could be a problem .if possible with the unit off pour some water into your drain pan slowly if it overflows your drain line is probably clogged if it leaks without overflowing it may be a rusted or cracked drain pan (a lot are made from plastic) if it appears to drain properly you may have a problem with airflow or freon.
Old 06-20-09, 02:04 PM
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If I'm reading you correctly, you are saying that you are getting some sweating on the outside of the coil box, where it attaches to the furace BUT you are NOT getting a flood AND water is not leaking down inside the furnace section. Is that accurate? If the drain pan were rusted thru or the drain obstructed, you would have a lot of water leaking out.

1. get some plumbers putty and seal the penetrations where the tubes enter the cooling coil cabinet. Seal all penetrations, freon lines and drain lines.

2. get some contact cement and glue the end of black pipe insulation directly to the metal of the outside of the cabinet so it is airtight as well.

It's also possible that the coil cabinet is poorly/maginally insulated on the inside. You would need to partially remove the cover and look inside to check the insulation. normally I spray on contact cement [it comes in a spray can] and glue in new insulation to fix a problem like that. Actually I use commercially available products made for that situation but contact cement from HD will work just fine.

I'm not sure what you mean by drain in the ground. Are you talking about a French drain? An FD is a hole [maybe 8" round and 12" to 18" deep] dug into the ground outside then filled with pebbles/stones and then the drain runs into there. The idea is to keep the drain water from just forming a puddle or muddy place on the ground outside. if that is what you mean , then yes it should be free draining.

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