Which line require venting on 2 pipe steam

heatseeker1

Can anyone tell me which lines need air vents? Should they be on the supply line or on the return line? I currently have a one year old Gorton #2 on the return line but it spits water and makes a lot of noise at the end of the cycle.
I also have one Hoffman 75 on the supply line. It was installed about a year ago.

Steamhead

You should have vents in both locations, and neither of them should spit water.

What pressure are you running? Where is the pressure control set, and what type is it?

heatseeker1

I am running 0.5 lbs of pressure on a Pressuretrol.
The Gorton is sitting about six inches
vertically above the horizontal run of the return. A local plumbing person who has only made suggestions over the phone thinks the Gorton is spitting water because it may need to have been installed about a foot above the horizontal but he realizes that there may not have been enough space above the return line to place it at least 12 inches above.

Fred

@heatseeker1 , you can't get down to .5 PSI Pressure on a Pressuretrol. That .5 PSI on the scale on the front of the Pressuretrol is actually the Cut-In pressure (pressure at which the burner will fire, if the Tstat calls for heat. Inside that Pressuretrol, there is a white wheel. What is that set at? If it is set at "1", that is the Differential which means the boiler has a Cut-Out of the .5 PSI plus the "1" PSI for a total Cut-out
pressure of up to 1.5PSI. Typically, that's fine but Pressuretrols, while set properly need to be recalibrated, from time to time to make sure they are reasonably accurate. They can allow the pressure to build up to several pounds, even thou they are set properly. That's why we suggest you install a 0-3 PSI gauge on your boiler, in addition to the standard 0-30 PSI Gauge. The 0-3 PSI gauge will actually let you see how much pressure there really is during a heating cycle. Depending on the type of 2 pipe system you have, you may even want to consider a Vaporstat. They allow you to adjust pressure down to ounces rather than pounds.But first things first. Put a 0-3 PSI gauge on the boiler.and see what's going on.

EBEBRATT-Ed

Lower the pressure as much as possible. Raise the vent as much as possible. Locate the return vent 18" back from the end of the main.

Pictures of the boiler and near boiler piping will help

MilanD

I second what @Fred said.

Pressuretrols can be very inaccurate. Get a good 3 psi gauge so you can monitor. 2pipe systems are generally vapor systems and are best when operated below 1 psi.

Fwiw, your vents also may be stuck open or are not seating properly when trying to close. Sometimes debris can get stuck in the vent and prevent it from closing. IF the vent is relatively new, unscrew it and try to shake it out, or blow some compressed air from the bottom and the top and see if that helps. IF they are old, try getting new vents. Everyone here including myself is very happy with Big Mouth from Barnes and Jones. It's a fairly new vent on the market. It can be purchased from Amazon (search 'big mouth vent'), or send message to Peter with Barnes and Jones through this platform (@Sailah - he'll be getting them out in a few weeks on Amazon). BTW, those are excellent vents!

Jamie Hall

You may have -- probably do have -- a pressure problem. However, if that Gorton is on a dry return, as your comments seem to indicate, you have something else going on as well. There should never be enough water in a dry return to cause a vent to spit. Your pressure may be way too high, backing water out of the boiler into the returns, or you may have a piping problem. I take it that this return is near the boiler? Perhaps a picture or two of the near boiler piping?

Steamhead

Big Mouth vent won't work here. It lacks a float to close against water. Remember, this is a dry return on what sounds like a Vapor system, so it's a "B" dimension rather than an "A" dimension. Water will back up into a "B" dimension much more readily than an "A" dimension.

To the OP: Turn off the power to the boiler, then remove the cover on the control. Inside, you should find a white wheel with numbers on it. This sets the differential between when the control stops the burner and when it re-starts it. Turn this wheel down to 1.

You should also check the pigtail (looped pipe) under the pressure control. If this gets plugged, the pressure control won't be able to sense the boiler pressure and stop the burner at the proper pressure.

If you still have trouble, the next thing to check is whether the return line near the floor level is clear. If not, have it replaced.

You can also replace the existing pressure control with a Vaporstat that cannot be set higher than 1 PSI.

Where are you located? We may know someone who can help you out.

Gordo

@heatseeker1 : I believe a 16 oz/in2 vaporstat was put on your system, as well as a three psi gauge. I could be mistaken.

Once the vaporstat was installed, there was no more water hammer nor spitting vents. That is what I remember.

Unfortunately, all too soon thereafter, the vaporstat failed (most likely caused by the wild water fluctuations due to the oils from the re-piping you had done) and a local person was called in who misread the units on the vaporstat as 16 psi/in2 (!) and sold you another pressuretrol to add to your collection of two others. Or so I was told.

You also had two large convectors at the front of your house that do not heat very well or at all because for some reason the steam is not getting through the supplies to them. The valves were broken and could not be removed and in the time allowed. The steam lines to the convector, especially the living room, appear to be clogged with rust. The return lines were found to be clear. Possibly, I am in error.

Also, not a few of your other traps may have failed open and can allow steam into the dry return. Adjustments were made with the inlet valves to temporarily stem the steam from getting by and one trap in the dining room (a Hoffman17A) was rebuilt. Or I could be wrong.

As with most convectors, they tend to get choked with dust and such over the decades of use and a complete cleaning of the fins can do wonders. That has been my experience.

As with most systems with steam convectors, the boiler quickly fills the small steam spaces and begins to short-cycle madly in spite of considerable down-firing. This also did not help the vaporstat to survive. Others may disagree.



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