Uneven Heat in mild weather/Venting?

jeff_50

I have a one pipe system with two mains. One is 46' vented with two Hoffman 75s, the other is 53' vented with a Gorton #2. The pipe diameter is 2".

Now that the weather is less cold, my system runs less
even. During a heat cycle last night, I noticed that the Gorton at the end of the 53' main never got hot enough to close while the two Hoffman's did. I checked the rads on the 53' main and found that some had heat, partial heat, and no heat. I checked the Gorton and there was no blockage. As long as it's fairly cold, all the rads come up nice and even. Do I still need more venting on the longer main?

Thanks (as always).

t. tekushan

venting

I recommend more venting on the longer run, until a point is reached where the main vents all close around the same time. The radiators are more likely to get steam around the same time this way.

You could put a T and an elbow or T and two elbows with two vents off the same riser. In any case, it should look like a tree with two vents on it. I think this will help.