Double trapping on Two pipe

Solid_Fuel_Man

Was at a job yesterday where the maintenance guys installed a new steam unit heater. They are running the condensate uphill in two lifts each about 24".

Piping goes like this, out of bottom heater horizontal 4' Ystrainer, float trap, vertical 2', horizontal 30' float trap, vertical 2', horizontal 50' back into common condensate return. Nothing is insulated in the entire 40,000 square foot facility and they run at 5psi....

There is of course no heat to this new heater. The vertical piping is due to roof pitch and the condensate return 4' above this heater. Industrial facility.

I am unsure of how anything is pitched or if it is totally level. Both steam and condensate pipes are 1 1/4 iron.

Jamie Hall

I'm no expert on these things, but... seems to me that the first trap would probably be fine. Water comes in, float rises, trap opens, pressure pushes the water up to the next level. But... when water gets to the next trap up there and the thing opens, where is the pressure going to come from? By that time the first trap is closed. Unless you got real lucky and got both traps synchronized...

Solid_Fuel_Man

That was my initial line of thinking as well Jamie. I am a water guy, so things with traps are mysterious.

Pumpguy

IMO, second downstream trap should be removed.

Easiest solution to this problem is to have first trap discharge downhill into a small float operated condensate pump. Pump then acts as a mechanical condensate lift up to higher return line.

If this is a gravity return system, condensate pump's receiver should be vented to atmosphere. If this is a vacuum return system, condensate pump's receiver should be vented back to a vacuum return.

This is a classic mechanical lift application. I can provide piping drawings upon request.

EBEBRATT-Ed

Condensate pump as mentioned is one way.

The other way You only need 1 trap, 2 wont work. Drop down from bottom of unit heater at least 12-14", strainer, trap check valve on trap outlet. after check valve rise immediately straight up above top of return line and drop into top of return. Let gravity take the condensate back to the boiler.

If the return line has to go up in steps, not so good but with 5 psi at the heater inlet this will raise the condensate up to 10' you only have 4' so it should work.

If it is only a float trap you could be air bound. The trap should be an F & T trap. The air will come out back at the vented condensate return tank

Size the trap for the btus or lbs of steam the unit heater is rated for x 1.5---2.0 for a safety factor to take care of the warm up load

Solid_Fuel_Man

Thanks guys, I have not been back to that site to see what has transpired. I suggested they try removing the innards from the second trap. Not sure if they are F&T or just float. I was not involved with any of the install/piping.