Low Pressure/Vacuum Systems/Heating Problem

Concerned Apartment Owner

The reason we were given for replacing the traps was to "Help distribute steam to the apartments and the apartments above." These problems happened last heating season as well. As far as the bathroom radiator. It was working fine at the beginning of the heating season. Have had problems since the thermostatic disk was installed. Is hot once the trap seal is unscrewed and the water and air drains out. Our building is using a VariVac system. Not sure of the size. Building is 29 stories. I plan on getting the book as well. Very interesting topic. Thanks for your help.

Concerned Apartment Owner

Low Pressure Steam/Vacuum Systems/Heating Problem

Thanks for reading this. Live in a highrise building, 29th floor,with low pressure/vacuum heating system. Having a problem with three radiators in my apartment. All the disks in the apartment were replaced this year. One radiator is not hot. The supply valve leading to the radiator is hot though. Sometimes when the heat is on there is a ticking sound in the second radiator. At other times half the radiator, ie the half farthest from the supply valve and closest to the steam trap is cold. This seems to happen when the heating units fan is running. The bathroom radiator no longer heats up. Had the handyman look at it. He opens the trap and lets the water out. Seems to work for a while then goes cold. I mentioned it to the building manager and he had the steam pressure turned up and hence more steam being used. When the pressure is increased this seems to work except for the bathroom radiator. So what's my question after all this??? I'm curiuous to know if problems such as this can be fixed without using more steam or balancing the pressure differential between the supply and return lines. Thanks

Christian Egli_2

And increasing the pressure did not work

You mention vacuum, does your building have a big vacuumizer pump downstairs? Has it been bypassed?

The problems you describe seem related to return lines that have become pressurized with steam.

They thus would no longer allow air to flow out of your radiators (which would stop them from heating), this pressurization could also work steam backwards the wrong way around your system.

You also describe mild water hammer which is consistent with return problems.

Remedies:

Reduce the boiler pressure.

Inspect and / or replace all thermostatic traps in the entire building.

Look for double trapping and master venting ill thought solutions someone may have installed on your system. Immediately delete any such configuration.

Get the building manager to read all of Dan Holohan's books.

Why were the discs in your radiators replaced? and was that the start of your problems? What other work was done at the time?

Other appartements having problems?