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MurphyMan 09-10-2012 05:08 PM

Heat Pump Condensate Leaks
3 Attachment(s)
Hello Experts.

We bought a house with a 20 y.o. Carrier heat pump that seems to be working well. Had a contractor check it out when we first moved in, last winter.

The old condensate line was previously plumbed into an open sanitation drain in the crawl space. I corrected that by closing the sanitary completely, and running the condensate out and away from the house.

There is a second heat pump Fujitsu, with the air-handler mounted on the second floor. It also had an improper condensate line.

I ran a new line from the Fujitsu, down to the Carrier drain, into a P-trap, then outside the house. When I installed the new drain line, I double verified good slope and free drainage. So far, so good?

All summer, the condensate line has performed it's job, and we can verify by the big wet spot out in the yard. However, there sometimes is a little stream of water coming out of the bottom of the air handler and draining into the garage floor drain. I have a humidity indicator in my conditioned, encapsulated crawlspace, and it has been higher than I expected all summer.

I think what may be happening is that extra water is trickling down the fiberglass insulation on the inside of the air handler, and is evaporating into the conditioned air.

This afternoon I looked a little closer at the unit and ran a brush through the primary drain. I also noticed that there is a small overflow hole right next to the drain connector and it seemed to be clogged with debris.

So, I cleaned it all out and will wait for another hot and humid day to see if we get the trickle on the floor again.

Is there anything else I should consider? Are my connections for the drains and P-trap on track? Any other suggestions?


MurphyMan 09-10-2012 06:29 PM

Hold My Horses

I put everythig back together and figured that everything would work right. An hour later, my wife tells me that it's leaking again? WTF? :furious:

I took the top panel off and saw that the condensate tray just had a little water in it, but the coil was spraying water all over the whole compartment! The drain apparently has nothing to do with the problem.

I thought all the water was supposed to trickle along and down the coil, but instead it's all over the place.

So, now what? Is the fan going too fast? Is this normal?

Thanks for any suggestions.

JJboy 09-10-2012 07:22 PM

Clean the coil:thumbsup:

MurphyMan 09-10-2012 10:04 PM

The coils look clean, and maybe the pro cleaned them last December.

Should I get some coil cleaner solution from the local HVAC supply house and have a go at it? What can I mess up?

JJboy 09-10-2012 10:22 PM

Also look for crack at the drain pan around the coil.

MurphyMan 09-11-2012 06:36 AM

No cracks in the pan. I even poured in a couple quarts of water over the coil to verify drainage. All good there.

I need to learn more about how dirty coils can cause excess moisture. Sure, I fully understand how visible dirt will muck things up, in all sorts of ways. But my coils look clean. Can they build us an invisable surface coating that will cause grief?

MurphyMan 09-15-2012 03:58 PM

New information - still need help
The coil is still dripping water.

I was at my local HVAC supply store the other day and ran into the guy that installed my system in a previous house we owned. Nice guy.

I told him about the dripping problem and he asked "What brand"?
A. Carrier, Model FA4A. Bryan was very familiar with the problem and said he tried everything when he took service calls, trying to fix it. Cleaned coils, slowed down the fan, etc.

He said that air handler combined with the slope coil caused all sorts of problems when first introduced. He said at the time Carrier issued a retro-kit to fix the problem. He said they issued them for free, at least at first. Apparently my air handler never got the upgrade.

He said it was it was a series of very thin strips of aluminium, placed just downwind of the coil, and they collected the water to deliver to the drip pan.

I am trying to find this kit somewhere on the web. I have downloaded all the manuals for this unit and fail to find any mention of the kit.

Anyone familiar with this kit and know where I can get one? I can't seem to fine the air handler model on the Carrier site. If I had a part number, I might be able to find one on Ebay.

hvactech126 09-16-2012 09:16 AM

What is the full model number? (need to know what size unit you have)

You need : Downflow Conversion Kit
Fan coils are shipped from the factory for upflow or horizontal--left applications. Downflow conversion kits provide proper condensate
water drainage and support for the coil when used in downflow applications. Separate kits are available for slope coils and A--coils.
REQUIRED USE: This kit must be used whenever fan coils are used in downflow applications.

KFADC0201SLP used on systems up to 3 1/2 tons
KFADC0301ACL used on systems 4 tons and up

MurphyMan 09-16-2012 10:11 AM

The Air Handle model number: FA4ANF036000BAA

Product # FA4ANFO36

S.N. 3894A00856

Thank you for your help, however, I'm not sure that those part numbers are what I'm looking for, at least according to what Bryan told me. I did find one of those part numbers on Ebay, and the photo of the kit doesn't look like the parts Bryan described. In the meantime, I'll pull the cover off my air handler and see if I can determine if that kit has been installed or not.


hvactech126 09-16-2012 10:30 AM

KFADC0201SLP is the kit that your AHU would need. My guess is that only part of the kit was installed as it is necessary to convert your ahu to down flow. The other part of the kit has to do with condensate control. This is the only thing that I could find for any type of condensate issue for carrier equipment.

Just found this.....

MurphyMan 09-16-2012 10:38 AM


Originally Posted by hvactech126 (Post 1010917)
KFADC0201SLP is the kit that your AHU would need. My guess is that only part of the kit was installed as it is necessary to convert your ahu to down flow. The other part of the kit has to do with condensate control. This is the only thing that I could find for any type of condensate issue for carrier equipment.

I did a lot of looking too. Thanks for the link for the installation instructions KFADC0201SLP kit.

Looking inside the unit, I can't really see any parts that looks like the ones I see on Ebay. I guess I'll just order the kit and see what shows up.

hvactech126 09-16-2012 10:41 AM

Just found this.....

MurphyMan 09-16-2012 11:12 AM

2 Attachment(s)
I thought I had it figured out, but now I'm confused. The installation instructions, KFADC seem to be close, but they do not match the parts shown in the photo in the Ebay ad (attached). Also the bit of the instructions that I can see in the Ebay ad don't seem to match the ones you sent. Good try, though.

My unit seems to have a top coil bracket, with the gasket, but it doesn't quite match the one shown in Figure 4. Similar, though.

I have no idea what is shown in Figure 5 and I don't know how that would recent condensation from dripping off the coil fins above it.

Also, these are installation instructions. According to FADC, I would have to pull the coil out of the unit, a job that is about five levels above my pay grade.

Finally, Bryan said it was a retrofit kit and I have found nothing resembling it.



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