how run a/c condensate drain - old house / no basement sink or drain..

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  #1  
Old 09-28-13, 04:01 PM
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how run a/c condensate drain - old house / no basement sink or drain..

Bought an old house w/ furnace & AC in basement but no sink or floor drains to run the HVAC condensate drain into. Previous owner had drain running into adjacent crawlspace, creating musty crawlspace smell..

Temporarily routed the drain into a 5gal bucket, was surprised to find water collecting even during heating.. sure enough, high efficiency furnaces create moisture.

Is it safe / acceptable to add an open drain w/ p-trap to the main stack (have a few stub'd branches available from previous plumbing adventures)? Will the A/C & furnace keep the trap primed or do I need to worry about it drying out?

In Michigan so not sure an outside drain is feasible due to freezing..

Thanks in advance!
 
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Old 09-29-13, 04:53 AM
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Research a condensate pump and pump it into your sewer line. Drill and tap the sewer line to accept a 1/4" mpt fitting. Using a 3/8" barb X 1/4" mpt fitting put that into the drain line and then connect the 3/8" ID hose from pump to the sewer line fitting. Most condensate pumps have a check valve in the hose fitting so you don't need to put a trap in the hose.
 
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Old 09-29-13, 06:09 AM
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Thanks for suggestion - I didn't mention it above but a condensate pump is already installed.

From what I've read, running the drain directly into a sewer line is a no-no? Most info I've found suggests an air gap is required. Is a check-valve durable enough to be considered acceptable?
 
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Old 09-29-13, 10:33 AM
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I've seen water damaged caused by an open drain connection into a sewer vent.
I like the idea of using a trap, but a solid connection would prevent water damage the day that trap fills with slime.

I'd install a T on the drain side of the trap and a pvc ball valve between the T and the pump, so that you can valve off the pump and blow out the trap annually. Pouring bleach into the T should help prevent slime build up.

I'd probably install a screw cap on the 3/4" PVC tee, but an open vent on a 2 foot piece of pvc above the Tee would be another option. (The pump on the drain would not allow me to have an open connection anywhere with the amount of water damage that I have seen over the years)
 
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