Radiator valve issues... not the one that is always asked about.

NewJerseyKirk

Hi all,

Big thanks in advance, have found this place so helpful. So jumping right into it, the vents on my single pipe steam radiator system open for really long periods of time letting out what I can only assume is a lot of steam (we've been having to add water every few days, more when we had that super cold snap recently - I also held a glass up to the vents and it definitely is at least some steam coming out).

Here's the catch, they open when the radiators are completely up to heat (they are very hot and its across the entire radiators), so not at the beginning when the system is warming up, and it isn't just one, its many different radiators that do it. I have replaced the valves with many different types and openings.

I've called the company around me in north jersey who is highly recommended as a steam heat expert and here is all the things they've tried.

• Replaced all the valves (again) with their recommended brand and opening, and rebalancing the radiators.
• Swapped the main valves from 1's to 2's, (there are two main valves).
• Drained, skimmed, and serviced the radiator.
• Cleaned the pigtail and reset and tested the pressure gauge.

They mentioned we can try adding another main valve to one of the lines which doesn't have one (I think) and maybe that would work? But I'm a little hesitant because in addition to already spending a chunk of change on this if the radiators are all heating up, isn't that showing that air isn't the problem? There also isn't a lot of banging or anything. And why would it take so long for them to close then?

A bit more info, it's an old house (1885) and the system isn't the prettiest. There can be a lot of surging in the site glass, and the water is pretty dirty especially at the beginning of the season.

Thank you all in advance for your help!

Jamie Hall

If there is actual steam coming out of a vent on a radiator, there are only two possibilities: the vent has failed open or you are running excessive pressure. And the latter — excessive pressure — will cause the former in time.

jesmed1

I'm not an expert, but I'll ask the obvious question. What pressure is the boiler cutting out at, and are you sure it's cutting out at the right pressure? The pressuretrol can be set correctly, but if it's out of calibration, it won't actually cut out at the set pressure. A number of steam users here have noted in past that their pressuretrols were out of calibration.

EdTheHeaterMan

There are different parts of a one pipe steam system that often are improperly named when describing a problem. by using the incorrect name, that sends the professionals in the wrong direction for problem solving. Here are some names of common parts that often are called something that they are not.

Radiator Valve: This is an actual valve with a handle that you turn to open and close. It is installed on the steam pipe that just at the entrance to the radiator. On a one pipe system, it must be either fully open or fully closed. There is no throttling of the valve at some midpoint in order to reduce the steam to a lesser amount that full open. Doing that will often block the returning condensation from the radiator to the piping system.

Radiator Vent. Here are two typical radiator vents one is adjustable and the other is a fixed orifice. the idea of this part is to allow air to leave the radiator so steam can enter the radiator. Where there is air there is no steam, so removing the air is an important factor in getting the radiator hot. once the steam is in the radiator, the vent should close as a result of the high steam temperature.

Main Vent. These vents are located at the end of a main steam pipe after all the branches to the radiators. The idea of this vent is to remove all the air in the steam main out so the radiators can all get steam from the main at the same time. In some larger systems you may find more than one of these vents on a tee fitting at the end of the steam main, just before it turns down to the condensation return piping

We often find some non professionals calling a steam vent a valve for one reason or another. when this happesn we look at the wrong end of the radiator where the actual valve is located for an answer to a vent question. Can you see how this can be confusing? I was wondering if you might restate you problem with this new information?

EdTheHeaterMan

these things are what you say are already done:

• Replaced all the valves (again) with their recommended brand and opening, and rebalancing the radiators.
• Swapped the main valves from 1's to 2's, (there are two main valves).
• Drained, skimmed, and serviced the radiator.
• Cleaned the pigtail and reset and tested the pressure gauge.

I believe you ment that

• Replaced all the VENTS with their recommended brand and opening and rebalancing the radiators
• Swapped the main VENTS from 1's to 2's (there are two main VENTS)
• Drained, skimmed and serviced the BOILER
• Cleaned the pigtail and tested the pressure CONTROL

Does this soung correct?

NewJerseyKirk

https://forum.heatinghelp.com/discussion/comment/1890572#Comment_1890572

Yes, sorry for the wrong terminology, that is exactly what I meant!

NewJerseyKirk

https://forum.heatinghelp.com/discussion/comment/1890568#Comment_1890568

Thanks for the reply, it's set to 1.5 but not sure if it is working / cutting out at that. Any way to test that? I asked them to check it when they did all the work and they said it was working, but it seems to set off the vents only after firing for awhile, which might mean the pressure has built up?

mattmia2

you can add a low pressure gauge in line with the pressuretrol to see the actual pressure, like a 0-3 psig or 0-5 psig gauge. sometimes they are calibrated in oz/in^2 instead of psi.

some have claimed that steam with a lot of carryover can cause vents to not get hot enough to close.

if the main vents are inadequate and/or if the boiler is very oversized the velocity of the air in the radiators could be propelling particles of rust in to the seat of the vent.

do the vents fail to seal immediately after yo replace them or does t take a few days or weeks. if you screw in a brand new name brand vent and fire up the boiler for a long cycle, do you see steam leaking out the vent on that first cycle?

you can also try boiling the vents in vinegar and rinsing them out, i'd try one and see if it makes a difference before doing all of them