Mastercool in window AC unit leaking


Old 06-22-18, 07:54 PM
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Mastercool in window AC unit leaking

I installed a Mastercool in window AC unit(model number MCP44C) and when the pump is turned on it continually leaks water from the overflow spout. I adjusted the water flow control but it keeps leaking. I put a bucket under the spout but I have to go empty the 5 gallon bucket about every hour or it overflows. Is this unit supposed to leak this much water?
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Old 06-23-18, 11:00 AM
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You posted in the air conditioning section.
You might have better luck in the evaporative cooler section.
Old 06-24-18, 09:00 AM
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I think there is a small (1/4") branch line that comes off of the pump discharge line and is directed to the overflow pipe. This feature is supposed to keep mineral buildup down by allowing the unit to add a constant stream of fresh water to the basin while the unit is running. If your water is isn't loaded with minerals you won't have any problems with capping/plugging this line.
Old 06-27-18, 09:32 AM
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You are right, I was able to plug that line and now it doesn’t leak, I have a water filtration system so my water doesn’t have a lot of minerals, thank you so much for the help
Old 07-01-18, 03:30 PM
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You still need to bleed off a little bit, water filtration or not. When water evaporates, it leaves behind a lot of crud. The water in the cooler will get salty in a couple weeks and your pads won't last as long and those things are expensive to replace.
Just cut the bleed off down to a really slow rate
Old 09-02-18, 12:32 PM
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I have similar problem. My unit is wall mounted on a carpeted sun porch so needs to be dry. Installer (handyman) said we didn't need several of the screws, 4 L shaped metal supports, 2 media support parts, and "notably" a 13 inch black tube about 3/8 inch diameter with a black fitting on one end. IS THIS the BLEEDER HOSE? Do we need it after-all? Can it be reconnected, and how?

He has adjusted the float several times but the unit is still leaking from the overflow outlet area, especially after unit is turned off after being run. Do I still have a float level problem? He says that drainage from wet pads adds water to the reservoir after being shut off. Do I have a defective float perhaps or still set too high to cut off the water supply? Unit is about 1 month old but I still have to keep a bucket under the left side under the overflow. I am not sure if a float adjustment or faulty installation. Suggestions???
Old 09-02-18, 03:34 PM
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Didn't he leave the instructions for your unit ?? This an evaporative cooler..... not a window A/C.

The units are normally mounted outside and the draining water is a byproduct of the operation. That small flow of water allows the old water to drain out allowing fresh water to replace it. That's one way that the cooler flushes out mineral buildup.
Old 09-03-18, 01:26 PM
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Thanks Pete, Yes I have the manual, and on line INSTALLATION AND OPERATING MANUAL, but not much help/confusing! . I plan on spraying the media pads with 1/2 cup white vinegar about once a month, to dissolve mineral deposits, and drain the reservoir when the cooling season is over to control the mineral build-up. (Did not buy the optional purge pump kit).

I am not a plumber, but I assume the float works like a toilet float, mechanically cutting off the inlet when level reached. I am still not sure what the black tube (described before) IS, or whether actually needed. Installer used a copper water inlet line, Diagrams seem to show a junction in the main water line, and some kind of connection through the overflow drain fitting to hang out the bottom of the unit with a nipple end, reinserted. Nipple can be open or closed, but not sure of it's purpose or where it attaches.

The unit leaks/drips from the "inside" of the overflow drain, which makes me suspect a float adjustment problem or a defective float. When running cooler with fan, it doesn't seem to leak. When I turn off the unit, the drips start, at various rates. I understand that gravity drains the saturated media pads after operation,which can cause the reservoir level to rise above the over-flow drain and cause leaking, As said in prior description, unit is installed on an un-heated, un-air-conditioned oleofin-carpeted "bust-out" addition/sun porch/entry to a mobile home, (yes, not a typical "outside" installation where drips do no damage!) Keeping a bucket under unit is unsightly for my entry. (maybe I could replace with a cold hardy plant in a pot that appreciated the watering???) Any suggestions/advice welcome.
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