I don’t know what else to do

Msteam1

I have a problem radiator. It’s a two pipe system, the inlet is on the bottom of the radiator. I have…

Cleaned out the condensation line of rust/blockage.

Disconnected the radiator and cleaned out with water to check for blocked cells etc.

Replaced the condensation trap.

Made a slope towards the condensation trap.

The radiator is on the first floor. I have radiators before and after on the second floor that are getting heat. (They are all fed on a large supply line from the basement.)

My issue is I’m only getting heat to maybe 3 cells out of 17 and it’s unreliable at best. There is an air vent installed and I have tried running it with and without the air vent. It is my understanding that a two pipe system does not require an air vent?

I’m at a loss.

Grallert

Is that radiator in the same space as your thermostat? There are a couple of reasons that radiator isn't fully heating up. One reason is the steam can't get in. Could be a blockage like water in the return a stuck trap. If some steam is getting in the valve is likely ok. another reason is the thermostat is be satisficed before the radiator fully fills. Can you put your hands on the return line from that radiator?

Can you get into the space below that radiator?

retiredguy

2 pipe steam radiators should not have a vent installed on them. I would check the steam supply piping for a blockage or a low spot where water can collect. Also, check the steam valve to make sure that it is fully open and not restricted in any way. Just because the stem of the valve is up does not mean that the valve is open. The valve could be broken. If all else fails, I would remove the radiator and use a compressor to blow compressed air through both the supply and return piping in a few short bursts. You said that you replaced the steam trap. Did you use a cage replacement or install a new trap? If the cage was replaced, make sure you got the correct unit and installed it correctly. Could you post a couple pictures of some rads that work better than this one?

bburd

On a system with radiator traps, there is always the possibility that traps on other radiators are stuck open and steam pressure in the return is preventing that radiator from filling with steam from the supply.

mattmia2

https://forum.heatinghelp.com/discussion/comment/1827665#Comment_1827665

sort of. it isn't the pressure but the heat from the steam closes the main vents(or traps) and the trap on the radiator before the radiator is finished venting. are your returns steam hot if you feel them?

another possibility is failed crossover traps on the main or water seals that were below the water line on the old boiler and are now dry with the new boiler. excessive pressure can cause steam to blow past water seals too.

bburd

Yes, traps are designed to close on temperature. If a trap fails open however, it may pressurize the return with steam. If there is steam in both supply and return pipes, there may be no pressure differential to move steam through some radiators.

mattmia2

https://forum.heatinghelp.com/discussion/comment/1827668#Comment_1827668

the pressure happens because the steam closes the venting on the returns before all of the emitters have filled with steam, not because of the pressure of the steam per se. If the system is working correctly the vents on the returns should never close except for in a few specific vapor systems

Msteam1

@Grallert thanks for the response. The thermostat is not in this space. The radiator is cold and the heat system is on for substantial time. No there is no return steam to the return line. I will plug the “air vent.” yes I can get below to access supply and return lines.

Msteam1

@mattmia2 A fair bit of that is over my head…there is not steam to the return lines on any of my radiators functioning or not.

Msteam1

@retiredguy it’s a 2” supply line so I’m fairly confident it’s not obstructed. It COULD be a failed supply valve. I will check that. Yes I replaced the cage unit. This is the same style unit and the replacement I found online.

as for functioning rads I have 14 upstairs and 7 downstairs currently.

Msteam1

@bburd non of my returns have steam in them.

mattmia2

https://forum.heatinghelp.com/discussion/comment/1827698#Comment_1827698

they feel cold? check especially where the vent is on the returns. the vent could be bad too. or missing.