Main vent recommendation?

danmayer175 · January 20

My main is 65 ft long and about 1.5 cf volume. I have a single Gorton #2 on it now. Is adding another #2 worthwhile?

Long Beach Ed · January 20

Try running it with the vent removed. If the main heats much faster than with the single #2, then another addition may be indicated.

dabrakeman · January 20

Make sure this test is run with the system well warmed up both times. Typically one Gorton #2 would be considered enough for that volume though.

Big Ed_4 · January 20

What is the problem as to ask ?

danmayer175 · January 21

I ran two tests with the header already hot. Open 1/2" bushing saw steam in 2 minutes. With the #2 it was more like 3:30.

danmayer175 · January 21

https://forum.heatinghelp.com/discussion/comment/1836594#Comment_1836594

Last runout is slow to heat up.

delcrossv · January 21

What's on that runout? What vent on the rad? Riser to second floor?

Steamhead · January 21

https://forum.heatinghelp.com/discussion/comment/1836643#Comment_1836643

https://forum.heatinghelp.com/discussion/comment/1836644#Comment_1836644

Add the second #2. This will get steam to that last riser much more quickly.

danmayer175 · January 21

https://forum.heatinghelp.com/discussion/comment/1836664#Comment_1836664

There are 2 radiators, both have varivalves on middle setting. The second floor rad is slowest (and farthest from boiler). Every other runout is in the first half of the main, this one is the end of the line, just before the main vent.

dabrakeman · January 21

Obviously you can try slowing down some of the quicker radiators to help the balance. Adding the second #2 may help a bit as well. I would raise the main vents up on a nipple and antler. Looks like you have plenty of room.

delcrossv · January 21

What @dabrakeman said. You can also try a riser vent at the top of that runout and insulate as much of it as you can.

danmayer175 · January 21

I'm adding an antler tonight. I have the Gorton #1 that was on the main when I moved in, so I'll add that first and see if it helps. And then tune the Varivalves I have all over the house. I'm planning to replace them all, but it's a pricy proposition and this #1 is free to me!

danmayer175 · 1:16PM

I added the antler and the #1 last night. I think it's about 30 seconds faster. The last radiator vents a little quieter and seems to be heating up faster.

Steamhead · 3:17PM

Those street elbows don't have full-size 1/2" passageways. This can slow the venting rate. I'd change them to regular elbows and short nipples.

SteamingatMohawk · 3:36PM

Be aware that the varivalves do not shut completely. At the minimum setting they are equavalent to a #4. See the chart.

https://www.heatinghelp.com/assets/documents/Vent-Valve-Comparison.pdf

SteamingatMohawk · 3:36PM

Main vent recommendation?

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