- This topic has 4 replies, 4 voices, and was last updated 20 years ago by marcelg.
20 Apr 2001 at 10:51 pm #278962MasterPlumbersKeymaster
help!i am trying to get some advice on the condensation drain design for a combo walk-in cooler/freezer…we normally run the drain from the fan coil drip pans trapped to the back wall and on out to a floor sink leaving an air gap……..we have been told by a planchecker that we will be required to trap and vent (to the roof) the condensate line every 15 ft…..if this is true then we have over 100 units incorrectly installed!!!!Is this a new requirement?have you run into this before?… thanks in advance for any help/advice you could provide…..firstname.lastname@example.org
21 Apr 2001 at 12:17 am #299697SylvanLMP
Sorry but this sounds about right.
The code I use does allow up to 25 ft BUT it still must be roof vented and the roof terminal must be increased to 4″ to prevent hoarfrost.
Try getting a variance with a common indirect line like we use on commercial laundries
23 Apr 2001 at 1:58 pm #299698fourth year
In this area, condensate drains, since they empty to an indirect waste are not governed by the plumbing codes and the only reason for the vent is to prevent siphonage of the coil’s trap.
and the trap is only to maintain the positive pressure in the unit which is why the depth of its legs is determined by the pressure in the unit.
24 Apr 2001 at 11:24 pm #299699SylvanLMP
Even the simple basic (VERY BASIC) standard plumbing code Chapter 8 section 801 deals with this type of discharge.
If you want you can send me a private E mail and I am sure of my list members can help you in this area.
Have you considered the possibility to over size the waste and vent piping and asking the powers that be to allow you to use a single vent stack with branches above the flood level of the units in question?
The intent of the code is to set up minimum standards of protection.
If you can calculate your condensate rate and figure 1 GPM = 1 FU as per most MODERN countries and area’s where they have legitimate codes then you could size these lines hydraulically saving lots of roof penetrations and taking a heck of a chance of oscillation from l these roof openings causing trap seal losses
[Edited by SylvanLMP on 24 April 2001]
[Edited by John Aldrich on 25 April 2001]
13 May 2001 at 12:47 am #299700marcelg
What do you mean when you say “and the trap is only to maintain the positive pressure in the unit which is why the depth of its legs is determined by the pressure in the unit”.
I thought that a condensate line trap, in a walk-in fridge, was to protect it’s contents from cross-contamination in case the floor trap failed. Sort of a back-up prevention same as for the air break (usualy 1 in or pipe diameter from flood level rim) in case of a sewer back-up.
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