View Full Version : Air Handler Condenate Problems


Larryboy
08-12-2010, 03:47 PM
Been having issues with my new Trane heat pump air handler with overflowing condensate from every seam of the unit. Just could not believe that it was a mfg issue. I searched and search for an answer and finally found it. It's all about negative or positive pressure and the p-trap design. Water can easily be forced through the system instead of going down the drain, all the time wrecking havoc with water going everywhere.

Here's a link to the Trane pdf file, shared in my Google docs. (it was to big to attach at this site).

https://docs.google.com/fileview?id=18g3AJy9TGc4AGMv9D-apofhmFiE6pVg9sJYBKrXwqhAv1L0ReRTV6Seg9ZBY&hl=en&authkey=CNfYqowF

MrMark
08-12-2010, 03:53 PM
How are these systems designed to get rid of condensate? Do they require an outside drain or do they try to evaporate their water like some portable units do?

How would they get rid of the condensate if installed in a cellar?

bazar01
08-12-2010, 05:16 PM
How are these systems designed to get rid of condensate? Do they require an outside drain or do they try to evaporate their water like some portable units do?

How would they get rid of the condensate if installed in a cellar?

If the airhandler is above grade, it just drains to a PVC pipe drain to the outside of the house.
If the airhandler is below grade, you can use a condensate pump.
The key to properly drain the condensate inside the airhandler is the height of the trap to overcome the negative static pressure inside the airhandler.

hydramatic
08-12-2010, 06:00 PM
the sheetmetal man who built your handler, missed the stack height..or the A coil still has the instructions package taped to the underside of it...been there and seen that 20 times.

MrMark
08-12-2010, 06:37 PM
If the airhandler is above grade, it just drains to a PVC pipe drain to the outside of the house.
If the airhandler is below grade, you can use a condensate pump.
The key to properly drain the condensate inside the airhandler is the height of the trap to overcome the negative static pressure inside the airhandler.

So there is no such thing is self evaporation of condensate on these type units?

Airhandler is evaporator, expansion valve, and fan, correct?

would the pump have a float to turn it on when the reservoir becomes full?

I don't totally understand the trap concept on this, looking for more info/drawing if anyone has knowledge they would like to share.

totally off the wall question but why do I see so many roof mount AC units in residential areas in the central valley of CA (it's hot there)? What is the deal on these roof units, where are they popular and why?

hydramatic
08-12-2010, 07:20 PM
roof mount / noise abatement..harder to steal..meth and crack heads don`t have ladders

bazar01
08-12-2010, 07:55 PM
So there is no such thing is self evaporation of condensate on these type units? If you prefer that route, there is such thing as a 120/230V condensate management unit that boil off condensate.

Airhandler is evaporator, expansion valve, and fan, correct? Yes

would the pump have a float to turn it on when the reservoir becomes full? Yes it has a built it float switch in the tank

I don't totally understand the trap concept on this, looking for more info/drawing if anyone has knowledge they would like to share.

totally off the wall question but why do I see so many roof mount AC units in residential areas in the central valley of CA (it's hot there)? What is the deal on these roof units, where are they popular and why?

I guess as the previous poster said, for security? That will be a pain to service the outdoor unit

answers highlighted in blue

danski0224
08-12-2010, 08:23 PM
If the P trap is not right, it will not drain.

The specs should be in the instructions.

Problems are aggravated if the ducting & static pressure is not where it should be.

Plugged air filter, too.

Freejack
08-13-2010, 02:14 PM
I don't totally understand the trap concept on this, looking for more info/drawing if anyone has knowledge they would like to share.


The trap on the air handler drain is similar to the trap on a sink, in that it is intended to use water to create a barrier. In this case, the intent is to create a barrier between the negative pressure difference of the air handler plenum and the unconditioned space around the unit so that water can be evacuated out. If there was no barrier (ie a straight pipe or drop), the negative pressure in the air handler would prevent the condensate from draining.

The design of the trap should be such that the negative pressure does not have enough "lift" (to use a pump term) to draw the water out of the trap.

Jake

MrMark
08-13-2010, 03:15 PM
Thanks for all the info, guys. That helps a lot.