Utah Wildlife Forum banner
21 - 25 of 25 Posts

·
Registered
Joined
·
11,158 Posts
The user manuals on the furnace show "non condensing furnace".
So you might have another issue, if you had enough water in the trap to cause it to freeze and break. It doesn't sound "non condensing" to me. Thats a pretty big volume within the elbow to have been full of water.

-DallanC
 

·
Registered
Joined
·
4,553 Posts
Discussion Starter · #22 ·
trying to learn more....
...I'm no HVAC expert.


So, here's what I'm figuring out: I have a Bryant furnace (800SA series non-condensing) with an attached 3.5 ton evaporator coil (CNPH series). It's the evaporator coil that has the drain lines. I found the manual for this evaporator. It states under the Condensate Drain Line Connection section:
Condensate Drain Line Connection said:
A trap is not necessary on the condensate line. Consult local codes for additional restrictions or precautions...

...If unit is located in or above a living space where damage may result from condensate overflow, a field−supplied, external condensate pan should be installed underneath the entire unit ...

...As an alternative to using an external condensate pan, some localities may allow the running of a separate 3/4−in. (19 mm) condensate line (with appropriate trap) per local code to a place where the condensate will be noticeable

...If the condensate line is to be connected to a waste (sewer) line, an open trap must be installed ahead of the waste line to prevent escape of sewer gases.
My unit is in the attic, with two drain lines (primary and secondary) which are both plumbed to the outside of the house. The secondary is located where it would be noticeable.
The trap has nothing to do with air-flow as suggested by the youtube video in my opening post. It is only necessary if draining to sewer to prevent gasses -- like any other p-trap in your house. If I'm draining to the outside, no need for trap.

So, from this doc -- I don't need a trap.
I'm going to remove it.
 

·
Registered
Joined
·
634 Posts
The purpose of the p-trap on both the furnace and the A/C coil is to keep it from sucking in dust. If it were me, I'd use vinyl tubing that can freeze and not break. I'd also do the vent after the trap, so siphoning doesn't suck the trap dry. It's not just for sewer gas... But whichever you want. I'd also make sure there's enough vertical drop from the entrance to the trap to the exit so that it doesn't get sucked back into the unit.
 

·
Registered
Joined
·
15 Posts
I have been doing commercial HVAC for 28 years and have seen many units on roof tops with no drain attached to the unit at all and they have no problems at all. So I would just run a straight drain line out to avoid any drips that might ruin your ceiling
 

·
Administrator
Joined
·
21,923 Posts
This thread got me thinking so I looked at mine. Almost brand new furnace and a/c, installed in April or May.

You will notice that there is no P trap. When you put your hand over the upper pipe you feel air coming out, not being sucked in.

Get rid of the trap, maintain adequate slope and be done with it. That's my opinion anyways.


Sent from my SM-N976U using Tapatalk
Yeah. Some of this stuff is Building Code regs.

In high-humidity Illinois condensate traps n drains for air conditioners were a big deal, essential. Here in the low-humidity southwest Wyoming part of Utah they're not needed.
 
21 - 25 of 25 Posts
Top