Are my main vents broken shut?

Daniel_3

Who knows how old they are but I have two main vents at the and of my dry returns. One is a Dole 3B and the other is an Amtrol float type with a small screw cap on top (seems to be for a hydronic system since inside the screw cap there is a pin which depresses). Well after trying to blow through them there is no flow. I know this, that normal 1/8" rad vents should let air through yet it seems these don't let anything through so I'm thinking because they are fused shut permanently that's why it takes about 1 1/2 hours of burn time to get from 60^ to 65^ in the morning because the mains are not being properly vented. I'm already looking for new main vents as I type this. One piper steam with about 2,500 sqft. of living space. The mains are about 34 ft. and 39 ft. a piece and dry returns are about 35 ft. a piece.

Big Ed

Main Vents

1/8 tappings are too small for main vents. Should be repiped to a 3/4 tap. In the mean time use a Verivent from Heat timer. Very fast venting.

Improper venting would efect the balance.

William Faust

why a larger tap?

I assume that there would be no need to repipe the tap from 1/8" to 3/4" if the Heat-Timer VARIVALVE could vent air as fast as needed. Do I understand this correctly?

Daniel_3

The first vent from Amtrol is definitely a hot water vent. The Dole does flow air but slowly and with some strange sound as if it has some blockage. I am planning on getting some hoffman 75's so I'll deal until then.

Daniel_3

The Dole 3b is a 1/4" tapping

Daniel_3

I just noticed something in "The Lost Art" after considering the venting of the dry returns at the boiler area. Why should I spend the time venting the massive amount of air on the 33ft. long dry returns when I could tap and pipe up 15 inches two main vents at tht end of the main on the other side of the basement?

Steamhead (in transit)

You're absolutely right

and if you're using Hoffman vents, I'd use two #75s on each main with a #4A added to the longer one alongside the two #75 vents. You could also use two Gorton #1 vents on each main along with the Hoffman #4A on the longer one.

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Daniel_3

That's exactly what I'll do Steamy. Thanks!