Thread: Exhuast Gases from Condensate Tube

This setup (see photo) is emitting exhaust gas at the open end of the trap adjacent to condensate drain in the exhaust line. I can't imagine that this is permissible, but wanted to throw it out there before I rote it up. Am I missing something?

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MH: The equipment is sure missing a lot. Who was the installer, Rube Goldberg?

Originally Posted by Mike Hunger

..........before I rote it up. Am I missing something?

Yeah, the W in 'wrote'. Sorry, I had to do that.

Is that loop in the line forming a trap of sorts? If it is, I don't see how gas can escape. There must be enough pressure in the flue to blow the trap clear?

A.D - Yeah, I got a chuckle out of that comment... his cartoons were funny.

John - I have a sticky "w" key on my keyboard (yeah, yeah, good story ). There wasn't any water in the tube... probably blown out, but the velocity of the exhaust coming out of the trap end was pretty strong. Also, I can't figure out why the exhaust tube (PVC) is insulated. Anyway, I wrote this up - I wouldn't want any CO in my crawlspace.

Mike, drainage of the condensate that forms in the exhaust is normally taken at the bottom of the fan housing inside the cabinet. The drain line is normally connected to the condensate drain line as is this one. The things I see wrong is that the vinyl tubing has kinked and could block the line, and the trap clean out (not a good design of one) is not capped. The best resolution IMO would be to change out the running trap with a standard trap design, with the clean-out directly above the trap and capped and the drain connected down stream of the trap. The loop in the vinyl would need to remain and needs to be supported to prevent kinking.

Is it really a condensing furnace? If it is, where is the drain line from inside the unit?

I don't see any connection to the A/C condensate drain. Also, If there is exhaust coming out of the trap, there is a blockage somewhere because if anything there should be a vacume due to the greater amount and velocity of gas passing up and out of the vent pipe.

Originally Posted by wayne soper

I don't see any connection to the A/C condensate drain. Also, If there is exhaust coming out of the trap, there is a blockage somewhere because if anything there should be a vacume due to the greater amount and velocity of gas passing up and out of the vent pipe.

I think the fitting on the left is a T' into the A/C.

That tubed drain set-up used to be required on older 90+ units. I don't believe it is anymore due to the re-working of condensate tubing in the newer units. Beyond it needs cleaning, service and re-piping. Punt to the HVAC guy.

Originally Posted by Vern Heiler

Mike, drainage of the condensate that forms in the exhaust is normally taken at the bottom of the fan housing inside the cabinet. ?

+1

The first thing I thought of was the furnace was installed wrong, there is no way for the condensate to get out from the draft fan housing.

Also I don't see a condensate drain line from the cooling coil, is it on the other side of the cabinet?

Drip tee used to be provided by manufacturers,now they have a tee setup with a trap built in,,This drain should be installed after a p-trap off the coil ,running traps are not code. I was curious about why the pvc vent was insulated with armaflex?

To help the exhaust condense and flow better. I see the pipe insulated quite often. I would think that the condensation from the flue pipe should be connected on the outlet side of the trap. Putting it on the inlet could blow exhaust fumes into the air handler and cause co to enter the house.

Originally Posted by Cobra Cook

To help the exhaust condense and flow better. I see the pipe insulated quite often....

How would that help the exhaust condense?

The "clear" tubing might be to big allowing the flue pressure to push the water out of that so called trap. On newer units (Coleman) that have a secondary drain in the flue as shown, have a 3/8 hose for a drain.
Most just allow the water to flow back down the flue and drain out.
Several manufactures require the use of the factory supplied trap on the furnace condensate line too. This Coleman furnace with the extra flue drain had an factory supply condensate trap.

WHOA!! Looking again at that photo, they have the furnace flue gases piped right into the evaporator!! OUCH!! does it smell funny in the house and they complain of headaches?

The furnace condensate must go in after the evaporators trap!!

Wayne... are you referring to the "Venturi Effect"?, like in old carburetors?

Rod... yep, the coil drain is on the other side.

Craig... yes, I would also think that the drain should be after the trap. Makes sense. The house is 4000+ sqft, with high ceilings. Good thing. I guess I was just sitting there sucking up the CO while checking it .
BTW, this was a Nordyne (Frigidaire) unit.

Thanks for everyone's comments!

John, just to keep all of the lines at a constant temperature even in the off cycle, and then it also depends where the system is installed too.