Single condensate drain line for a Lennox C33 cooling coil and SLP98 FAU

[JKopp]

Condensate water cannot overflow or back up into the fau heat exchanger with this set up. Equipment is set in fau closet with a raised platform for return air. Home has very nice hardwood flooring all around this interior fau closet. With this mechanical switch I don't anticipate water damage from this installation. Without these safety switches a condensate back up on a call for cooling would fill the heat exchanger, overflow the fau vent/trap assembly and make a mess.

John



3/4" Cross tee allows for the installation of a safety switch to break the "Red".


Photo taken from the back of closet looking out at drain assembly and me.


Drawing of this drain set up.

[jimmyed]

Add on txv's? Lennox still in the stone age?

[SBKold]

So you write these manuals for lennox jkopp?

I have to admit they are by far the best instructions ive seen.

[JKopp]

Thanks SBKold, I have a passion for doing illustrations that are correct. So many of them are not correct. Some of my work has made it into Lennox install instructions. The coil condensate drain line drawing, equipment hold down method and equipment elevation extenders fixed and adjustable for the XC series units using 2" ABS fittings to name a few. I also have several HVAC related patents.

We purposely install coils with external TXV valves because we have had to replace a few. Much easier when they are external.

John

[SBKold]

noticed you posted on jimmyeds picture about combining puts positive pressure on fau but I'm curious what happens once water evaporates from the trap?

From the pictures of actual install I can see how your vent placement provides the solution.

However just going by diagram it does not stress the importance of installing the vent never perpendicular to air flow thru trap.

I also cant see the actual lower vent configuration in the install pics.

[JKopp]

One of the issues with our install is the factory FAU trap clean-out is going to be very hard to get to being this is a closet install. Then I am now reviewing Lennox's latest and greatest install instructions and they redesigned the trap clean-out. Maybe to make servicing the thing easier? They and I have both routed the drain line in front of this new horizontal clean-out. It would take installing a 90° fitting to offset the drain line over from in front of the clean-out depending on how much room one has. Looks like I need to rework my drawing.

[Bsmith816]

I myself always run evap coil dain and furnace drain completely separate. Lennox changes their condensate trap every month I think