DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   HVAC (
-   -   Furnace drain problem (

jkennedy99 12-27-2008 03:13 PM

Furnace drain problem
Hi, I purchased a new high efficiency Lennox G61V furnace a year ago, and have had problems ever since. After numerous visits from the installer, we've finally determined that water from the cold header box (which sit directly behind the combustion inducer fan), does not drain out until the furnace shuts down. So, basically if it is cold outside and the furnace runs for several hours straight, that water continues to build up and gets into the inducer fan, which cause all kinds of problems, and the furnace shuts down.

The service people I've used have called Lennox, but can not figure out why the water would not drain out until the furnace winds down or is shut off.

Has anyone run into this issue before? I'm a good $1000 in on maintenance fees right now and I'm not sure what to do at this point.

HvacWiz 12-27-2008 05:53 PM

Have the checked to see that the furnace is setting level or with a slight pitch to the front.

yuri 12-27-2008 07:10 PM

1 Attachment(s)
It needs an open 'T' on the drain line like this one and to be sloped slightly forward and level side to side. Also the discharge pipe from the furnace AND the black condensate trap MUST be on the SAME side of the furnace. If not it won't drain properly and water backfeeds into the ventor fan. There is an adaptor kit from Lennox if it cannot be setup that way. I have sold/seen 100's of those units and have had no drainage problems. Take digital pics of it with the front cover off and post them here and I may recognize the problem/with the other guys also.

jkennedy99 12-27-2008 08:16 PM

The furnance is level side-to-side. As I stand in front of the furnance, the level shows the furnance is almost exactly level, but it is just a hair angled to to the back. Is the normal set-up to be tilted slightly forward?

jkennedy99 12-27-2008 08:40 PM

3 Attachment(s)
Thanks Yuri, the furnace set up is an upflow position. The exhaust pipe and black condensate box are located on the same side of the furnace. The "T" you are referring to is in place (see attached pictures). There are two rubber hoses connected to the condensate box. When I pull off the condensate box (as the furnace is running) only the hose coming from the exhaust pipe has water coming out. The hose running from the large cold header (collector) box behind the inducer fan does NOT have water coming out of it. However, once the furnace hits the temperature on the thermostat and winds down, a good cup of water, or more, comes flowing out of that second rubber hose.

Let me know if you see anything on these pictures that does not look correct.

yuri 12-27-2008 09:01 PM

Looks reasonably good to me. I had a York unit with a similar problem and it needed to be sloped forward slightly. Get them to jack it up and slide a metal sheet metal S clip in to give it some slope. I would also check both the hose and ports from the collector box and the ports where the trap attaches to for blockage. They had a couple where the trap attaches that were not drilled out fully. You can also try run it without the burner box cover attached for a short while. That furnace should start draining within 3-4 minutes with the trap properly full/primed (longer if you drained it). If it does then the intake may be blocked/too long etc and possibly contributing to the problem. The pressure switch should stop the unit but that is still a possibility. I had 2 G26 units with partially plugged intake pipe which will increase the velocity of the flue gas entering the ventor fan and "carryover" water into the ventor fan. One had a burger wrapper get sucked in and the other was a wasps nest.
Good Luck

keithv51 01-25-2010 05:09 PM

Was there ever a resolution to this problem? I'm having a similar problem with the same furnace originally installed in December 2007. We detected the problem almost immediately and the installer has been very good about coming out to try to fix it but after replacing pretty much the whole furnace once and many individual parts several times we still have a problem. After running for about 40-45 minutes the furnace shuts down even if the desired temperature hasn't been reached. The error code usually shows 4-3 at that time, but sometimes displays 2-5. Sometimes the 2-5 code is displayed while the furnace seems to be running normally. The condensate drain has a steady drip while the furnace is running, but I'm not sure which of the 2 black hoses the drip is coming from. When the furnace shuts down I also get a fairly large discharge of water.

The furnace starts up again after some timeout. Once the desired temperature is reached in the house, operation seems fine -- we only see the problem if we need to raise the temperature more than a few degrees (like first thing in the morning).

The drain setup seems similar to what's in the posted pictures. The furnace is sloped slightly forward. From side to side, the large pipe that at least one of the 2 black drain hoses comes from is sloped slightly away from the side of the furnace the trap is on.

The installer got a Lennox tech to come out last week and they've suggested some things to change. However, I'm not very optimistic because it seems like he only suggested doing stuff that's already been tried at least once already.

yuri 01-25-2010 05:25 PM

Get your tech to read this service bulletin:
May have a partially plugged drain port.
Tell him to check the trap for small cracks and the port it attaches to. Can get airlocked if that happens. He should also remove and reinstall the trap and put silicone on the orings for the trap. Once again a TINY air leak can cause it to get airlocked/drain slowly.

keithv51 01-25-2010 05:37 PM

Thanks Yuri! I'm not sure the service bulletin applies. It seems to apply only to left side drain connections. I didn't mention in my original post, but ours is on the right. I'll mention it to the tech when he comes out anyway just in case.

I assume your other comments about checking for leaks would apply with either setup so I'll also discuss that with him too.

yuri 01-25-2010 06:00 PM

We have installed about a thousand of them so I am quite familiar with them. Blockage can apply to either side as it is an identical port fitting. VERY rare that we have drainage problems with them but my Cdn. Lennox tech guy suggests those other checks.

beenthere 01-25-2010 06:21 PM

Yuri dreams Lennox.

I think he went to school with Dave. :laughing:

yuri 01-25-2010 06:30 PM

Yeah. Started with Dave in 1978. Hooked up with Willis Carrier for awhile (rocky relationship). Beenthere myself a few times. LOL:laughing:

beenthere 01-25-2010 06:35 PM


Originally Posted by yuri (Post 389027)
Yeah. Started with Dave in 1978. Hooked up with Willis Carrier for awhile (rocky relationship). Beenthere myself a few times. LOL:laughing:

LOL... So you've kept your thumb on the pulse of things.

yuri 01-25-2010 07:00 PM

Yep. Mom still has one (son has spare parts). Going to pressure test one tomorrow.:)

Tator1076 01-25-2010 08:39 PM

I work on Lennox and the black cover behind the draft motor is on recall. The ports get plugged up time to time becasue too small. I just replace 10 of them all ready.

All times are GMT -5. The time now is 05:48 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1