2 out of 5 Radiators not hot


  #1  
Old 12-22-04, 05:17 PM
tommycjr
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2 out of 5 Radiators not hot

Hi,

I just bought a two story multi family bulding with a two zone oil fired hot water boiler. 20 pounds of pressure. I have two problems..

1. 2nd floor apartment. I could only bleed 3 radiators. The two in the front room would start hissing out air for a minute then just stop, no water, no air. I waited a few minutes, tried again and a little air, then nothing. I know the pressure is high enought because the others on the 2nd floor bled out water and are heating fine. The bottoms of the two faulty radiators are warm, up about 3 inches?.

2. 1st floor office, one radiator is real hot, the other is barely warm. I bled about 5 gallons out of the cold unit and still no heat, the water was just warm. The pipes to the radiator are very hot. It has just one port for the water into the radiator and I assume there must be a valve inside the pipe that let water in one way and out another.

Also, is there a good book on the market that would help educate me on the force hot water heating systems.

Thanks, Tom
 
  #2  
Old 12-22-04, 07:09 PM
A
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Location: Lake Murray, SC USA
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Tom - Welcome to the DIY Forums

If you cannot vent air until you get water out, most likely you do not have enough water in the system. Single best indicator is only the bottom half of the radiator will get hot......meaning there is not enough water to fill the rest of that radiator, or it has not been bled. If you do not know how to add water, check the previous posts for information about bleeding or auto-fill valves. See the first post on this forum on how to search for information in this forum. You need to be bleeding with the circulator not running. The pressure guage may not be accurate, so if there is not water to the radiator, there is not enough pressure, i.e. not enough water in the system.


You said "2. 1st floor office, one radiator is real hot, the other is barely warm. I bled about 5 gallons out of the cold unit and still no heat, the water was just warm. The pipes to the radiator are very hot. It has just one port for the water into the radiator and I assume there must be a valve inside the pipe that let water in one way and out another."

I don't understand what you mean by one port for the water into the radiator? What is a port? I have never seen a radiator with internal valves. Nor have I seen water flow in two different directions in the same pipe. So, please clarify. Do the hot and cold radiator appear to be different, or piped different? Do you know if they both ever worked before?

Post back and we will try to help you. Hit the reply button below.

I cannot recommend specific books, but if you go to the link below for the Bell & Gossett site, there is a wealth of information available.
http://www.bellgossett.com/
 
  #3  
Old 12-23-04, 05:14 PM
tommycjr
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Hi Rick,

Thanks for the suggestions.

I have two gauges on the boiler and one read 19 and the other was 21 so I assumed they were close and the numbers seemed right because I could bleed three radiators on the 2nd floor. After reading your post I decided to take a reading off on my boiler drain and it read 10 pounds, not nearly enough. I feed in more water until it read 20 pounds, then I started the circulators for about five minutes. The pressure dropped to 15 pounds. I added more water up to 20 pounds and went up to bleed the radiators. They blew out more air and then stopped, no water. I went back down to the boiler and the pressure was down to 13. I feed in more water up to 20 pounds and waited, I was thinking that I must be leaking water somewhere when I heard water draining down the vent pipe. I went up to the attic and there was a container with a sight glass in and the pipe went out the top and into the vent. Ah Ha. I went back to bleed the radiator and I got one to completely bleed, I added more water and the other radiator bleed water.
It is now hot in that apartment.

I still have the problem with the radiator in the office. Its stone cold and bleeds cold water, but the pipe that bring water in and out of the radiator is hot. There is only one pipe into the radiator. The pipe that carries the water comes out of the floor, attaches to the radiator and then continues back into the floor. The pipe is shaped like a sideways "C" with both ends of the "C" going into the floor and the radiator connected to the "C" at the midpoint. There must be a diverter at the midpoint that directs the water into the radiator and takes it back on the other side.

I have two of these same types in another room and they work well.

Thanks for your help, Tom
 
 

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