Contractor Talk - Professional Construction and Remodeling Forum banner

21 - 40 of 48 Posts

·
Registered
Joined
·
12,044 Posts
You want a capped T for negative, for a positive pressure system you want an open T. My HVAC guy doesn’t even put a trap in for the AC. The furnace trap is internal.
Don't bother putting the trap on it you have an open T (on either system). Totally negates the funtion of the trap.

Tom
 

·
Registered
Joined
·
6,409 Posts
Don't bother putting the trap on it you have an open T (on either system). Totally negates the funtion of the trap.

Tom
The inspectors wanted an open T because they said it prevents the positive pressure from blowing the trap dry and provided access to clean. Like I said though; they don’t even install them anymore around here.
 

·
Registered
Joined
·
12,044 Posts
As I've been saying a proper trap is needed. Only way to get a properly designed trap is to do the static testing and the math. Spent 5 years dealing with 40 roof top units. Biggest issue was the trap when the units were originally installed. Each unit ended up with it's own unique trap. I wish the trap in the video was available in the '90's, would have made my life easier.

You tell us they no longer use traps in your area. The video you posted shows how bad that can be.

Tom
 

·
Registered
Joined
·
10,826 Posts
As I've been saying a proper trap is needed. Only way to get a properly designed trap is to do the static testing and the math. Spent 5 years dealing with 40 roof top units. Biggest issue was the trap when the units were originally installed. Each unit ended up with it's own unique trap. I wish the trap in the video was available in the '90's, would have made my life easier.

You tell us they no longer use traps in your area. The video you posted shows how bad that can be.

Tom
I posted the video. We use traps. But we often come across some installer who claims "you don't need one."
 

·
Registered
Joined
·
6,409 Posts
You tell us they no longer use traps in your area. The video you posted shows how bad that can be.

Tom
That video only addressed negative pressure systems, I’ve never seen one around here, probably more common in commercial units.
 

·
Registered
Joined
·
220 Posts
Discussion Starter #35
You do realize the water is drawn wrong. They'd be even at the lowest point.
Not necessarily. The suction of the negative pressure would cause it to be higher on the equipment side. Thats why they give calculations for the depth if the trap.
 

·
Registered
Joined
·
220 Posts
Discussion Starter #37
Fortunate for whom? Not for the installer ... I’m declaring the installation not acceptable unless they can show otherwise. And since i have not paid them yet ...
 
21 - 40 of 48 Posts
Top