The case of the cold apartment, this Fridays case

RayWohlfarth

This case was a tough one to solve. The owner called and said one apartment was cold in a 12 story apartment building. The apartment building is close to 100 years old and so is the piping. The boilers were controlled by a Heatimer panel that cycled the run time according to the outside air. The outside temperatures reached the 40's during the day and the 20's at night. When we arrived, the apartment was around 64 degrees F. It was a two pipe steam system and the apartment had four cast iron radiators in four different rooms. The apartments above and below this one had heat as well as the apartments next to it. I thought it had to be something in common with all four radiators. Certainly it couldn't be four defective steam traps. That led us to the return pipes. I thought there was a blockage in the piping. The radiators eventually heated after the boilers ran for twenty minutes. The return pipes were not plugged or restricted.
As usual, I will tell you what I found on Friday morning at 6am EST when the video is published.
Ray

SgtMaj

Has to be an air issue. Wrong size radiator traps or cage units/bellows, wrong repair parts installed.

EBEBRATT-Ed

Bad traps in an adjacent apartment blowing through and pressurizing the returns in the apartment with no heat. Cold apartment can't heat due to trapped air in rads, steam pushing from both directions

RayWohlfarth

@SgtMaj and @EBEBRATT-Ed I had the same thought but the cause of the issue was the caulking was missing or cracked around the windows. It made the walls so cold, hit sucked all the heat from the radiator We discovered it by using our thermal imaging camera. At the time of this test, the outside air was around 36 degrees F. Here is the link to the video.
https://youtube.com/watch?v=9YJIFDuzw3Y

SgtMaj

@RayWohlfarth what type of radiator is that?

RayWohlfarth

Cast iron 

DJDrew

Cool lesson. Would be neat to go back and see the measured wall difference once the windows were sealed.

RayWohlfarth

Thanks @DJDrew I will let you know if I go back