The pan under the heater is full of water. I obviously have a problem with the drain line, but I can't figure out how water is getting into the pan. I don't see any leaks in the pipework above the pan but it has to be leaking from somewhere.

Any suggestions on the source of the water and any ideas on how to unclog the drain line?

The condensate line? Run hot water and see if it drips.

Did water heater stop working and then you found drain pan full? if so, was there an error code of some sort? I would start with removing the water from the drain pan first with a shop vac, towels, etc. Is it wet under the unit? did you do some maintenance on it recently? is the insulation wet under the unit?

Have someone run the hot water while you watch the unit. If it's coming from water heater, you should be able to see it dripping under the unit. You can take the cover off the unit as well in case it's coming from inside the unit. Is it an old unit and full of sediment or old heat exchanger?

Does condensate line share a drain with a/c condensate? if so, maybe that got clogged with algae and backed up?

I am guessing it is something to do with the vent condensation. From your picture I cannot tell if there is a condensate drain installed.

There is a fair amount of condensation produced in cold weather. Have to handle it properly.

My condensate line is behind my unit and its easy to see it dripping into the drain. I agree with previous poster about not seeing one in the pic.

The 1/2" pvc that comes from the center of the heater and makes a couple 90 degree turns is his condensation line. I have the same water heater.

I would hire someone to come check that and clean your unit (this should be done yearly at a minimum). Is the clear filter with rocks in it looking nasty?

AgResearch said:

---

The 1/2" pvc that comes from the center of the heater and makes a couple 90 degree turns is his condensation line. I have the same water heater.

---

So do I.. but my drain line has an open end that goes into a drain.
His seems to go into acid neutralizer, then drops below the insulation and who knows where.

Also that pvc on the left, that is coming off the blowoff/expansion valve, and it's capped. That is supposed to go into a drain.

Yeah the pressure release valve has me scratching my head. Is it capped off or the angle of the picture not showing another 45 or 90 degree fitting.

I did open up the hot water and could hear water circulating through the heater but it did not start dripping anywhere. Below are some additional pictures. I understand from the messages you guys have posted that this "condensate nuetralizer" with the part number CN2-VHB12 is some sort of filter. I also see that it recommends that it is changed out annually. This has been in service for 5 1/2 years and it's never been changed. Live and learn I suppose.

I have a plumber coming out tomorrow morning and I will watch him swap out this filter so I can do it myself going forward. I'll put it on a 2-year swap out in the residential PM system.

where does the pvc go after the neutralizer? Into the insulation and..??? through the ceiling/floor?

62strat said:

---

where does the pvc go after the neutralizer? Into the insulation and..??? through the ceiling/floor?

---

Yes, it goes to a drain line that sticks out the side of the house.

Like this?

Gus said:

---

Like this?

---

No. It is at the same elevation as the attic. It runs straight out horizontally once it goes into the insulation.

Ok, mine looks like above but with 4 pipes and the one smaller pipe at attic level is my a/c condensate overflow. I'm guessing that one of those 4 pipes is my a/c main condensate drain line and one is my water heater condensate drain line? Maybe your setup has the tankless water heater condensate tie into the a/c condensate line and exit the house at about attic level? I don't have an acid neutralizer but maybe that's because mine doesn't tie into the a/c? There is a p-trap however between the tankless unit and drain.

Why does this have a condensate line filter? Whats the point? Its condensation just let it drip off into the drain or outside....
I have the same water heater. Plumber didn't install a condensate filter. Don't recall seeing a recommendation for one. Putting a few cups of bleach down the line does the same thing without the need to get all filter plugged.

FunnyFarm14 said:

---

Why does this have a condensate line filter? Whats the point? Its condensation just let it drip off into the drain or outside....
I have the same water heater. Plumber didn't install a condensate filter. Don't recall seeing a recommendation for one. Putting a few cups of bleach down the line does the same thing without the need to get all filter plugged.

---

I know this is a new code thing that is coming to water heaters and hvac. Not really seeing it in dfw yet, but I've heard about it. I don't get the reasoning either.


To the OP. if it isn't the condensate drain, then it has to be either a leak in the unit or a roof leak around the vent pipe.

UPDATE: I had a plumber come out and look. He could not find a leak on the water heater itself or any of the plumbing. We cleaned the pan completely on Wednesday and on Saturday morning there was a small amount of water in the pan. What's bazaar though is that there was a slight amount of water in the drain pipe. It appears that there is water getting into the pan FROM the drain pipe.

I have blown air and sucked air with my shop vac from both ends of the pipe. I have traced the pipe as far as I can and can't find where any other drain pipe (such as A/C) that is tied into the drain pipe that could be feeding water into it.

I put a paper towel in the pipe where it enters the drain pan. I'll check it daily to try and figure it out. So it's still a mystery. I sucked over 4 gallons of water out of the pan so something is not right but unfortunately we've yet to find the smoking gun.

Clean and dry the pan and put a large piece of kraft paper or wrapping paper down in the pan. If there is a drip, this might help show you where it is originating.

Like someone mentioned above, I believe it's a new code enforcement due to the acidic nature of the high efficiency units. They don't want it draining into sewer but I think it's ok to drip onto vegetation, but the drain has to be no higher than 6 inches off the ground like in the pic.

Maybe with the recent cold weather, there was more condensate in the line than usual and it backed up? Maybe the new filter will help? If it was dripping above pan, I would think there would be some splash collateral (new term?) around the pan?

Like mentioned earlier, you could clean the drain with vinegar or bleach once a year like an a/c line?