condensate drain trapping

[wakaru8]

I've been perusing through the Residential and Wall of Pride forums and have a question about condensate trapping on condensing furnaces. If the condensate is draining from furnace through 3/4" piping and into a pump, would a drain trap still be necessary? This an upflow system, a-coil on top, and condesing furnace. I haven't seen alot of pictures in the wall of pride section showing drain traps on some 90% units and was wondering what people are doing.

[tecman]

You should have a trap in almost all instances.

Read: http://www.trane.com/commercial/issues/iaq/iaq5.asp
for the long story on traps.

paul

[trane]

There is a trap in all 90% furnaces already so I never trap them again.

[t527ed]

what trane said

[dhvac]

long answer made short you PROBALLY do not need a trap if you are using a 90+ and a condensate pump

however a trap would not hurt

[dave and julie]

Thanks for the article. I'll be putting a trap on this weekend.

[trane]

Great, now all 90,s are going to be double trapped. It won't hurt but it also won't help. All you are doing is adding a likely place for the drain to cause future problems.

[wakaru8]

I see. Thanks everyone for clarifying.

[dave and julie]

Originally posted by trane
Great, now all 90,s are going to be double trapped. It won't hurt but it also won't help. All you are doing is adding a likely place for the drain to cause future problems.

I have an 80 and no trap between the humidifier and condensate drain. My drain is plumbed directly into the sewer and there is a trap there, but it has occoured to me that since there is an opening at the humidifier where air can be sucked in, and a place for it to go into the air handler through the drip tray, that I need another trap.

[square2round]

I've been told when using a condensate pump, no trap is needed. Therefore, I've never installed one when using a pump. If this is incorrect, please clarify so I can correct this.