Steam Main Venting

Malcolm_3

I have an 18 unit apartment building. One main is 81 feet with 3" pipe. At the end of this main is a first floor unit that is cold with the 2nd & 3rd floor is ok while the units before the end unit are overheated. The other main is 43 feet with 3" pipe and these units are over heated also. Both mains have Vent-Rite #75 at the ends of the returns.

Could you tell me what the venting should be for the mains?

Also if there is something else that I can look for that could be causing a problem.

I have a Heat-Timer MPC-7 that went bad and was told it could not be repaired. It's too old, no parts.

The replacement for this model would be the MPC Platinum, a bit pricy. I have looked at literature for the Tekmar 269. Any inputs to these or if there are any other controllers that could be considered?



Thanks

Steamhead

I'll bet it takes forever

to get steam to the ends of those mains. Both your Vent-Rites are too small. Vent the longer main with two Gorton #2 vents, and the shorter one with one Gorton #2. Run the presure low- under 2 PSI- and that should solve your overheating problems.

I'll let the outdoor-reset gurus tackle the Heat-Timer/Tekmar question.

www.gorton-valves.com

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