I am new to this place and looking for help. Just feel that I wanna try to fix my heat system by myself rather than waiting for (really sucking) pes&g guys.

Repairmen came days ago and was bleeding the system. Now the radiators on the 2nd floor is warm, but the ones on the 3rd floor are not. I tried to bleed at one of the radiators on 3rd, water came out, it turned warm for a while but again became cold very soon. When I check in the basement, one of the pipes on the top-left corner of the picture is hot, the other is not (as marked in the pic)



That is a brief look at the heating system (boilers and pipes) in the basement. On the top-left corner there are 2 pipes which, I believe, come into 2nd and 3rd floor of my apartment. No other valves are found. The pressure meter is provided because I want to know whether that is too low pressure.

Any idea why this is happening and how I should solve that?

2 Answers 2


Judging from your pressure gauge your system pressure is far to low. You want the system to operate between 15 and 20psi. You need to make sure the pressure reducing valve is operating correctly and adding water/pressure to the system. Also make sure there is no valve closed going to the boiler fill line and pressure reducing valve. Some systems will just have a regular valve and it is up to you to add the right pressure to the system and then close the fill valve once complete.

You will also have to bleed any air from the system. You will need to have the system fill as you bleed it or else you will just remove more and more pressure instead of purging air.

If you can purge all the air and have the system fill back to 15psi your issues should go away. You will have to bleed out every radiator in the system to properly purge it.


You probably have a airlock in the pipes leading to the 3rd floor. If water can come out when you are bleeding then there is enough pressure.

Close all other radiators and see if that will clear it.

Otherwise the return pipe is not connected properly or just clogged. That is harder to fix.

  • Thank you! I closed all other radiators with a switch before posting the original thread and unfortunately that didn't solve the problem. Will the airlock go away if I bleed longer?
    – AlgRev
    Nov 23, 2014 at 18:43

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