Balancing hydronic system

John_54

I have a 24 unit 4 level apartment building about 50 years old with hot water heat. I had some work done this year on a couple of radiators this year and the tech turned off the two taps that control the water flowing to each of the 2 zones. These were turned back on when the work was complete but since then I have had to turn up the water temperature at least 20 degrees to keep the apartments on the 4th floor on the left side (furtherest from the furnace) of the building warm. No complaints from anywhere else. I have a feeling the valves were balanced which we have lost. How can I re-balance the system. I only have the two valves splitting from a common supply and 2 return pipes with separate circulators.

The radiators in the problem apartments are all warm and they have autovents so there is no air problem. The circulators were new at the start of the season and the pressure is fine.

Tom Meyer

Question

Before we start wondering about system balance, a question:

What work was done on the radiators? Are there shut off valves in the apartment on either side of the radiator?

Tom Meyer
Senior Designer/Trainer
Precision Hydronics Corp
www.precisionhydronics.com

John_54

I had a couple of rads that weren't working. One had 50 year old construction debris (cement) in the pipe which was cleaned out. The other needed a valve on each pipe so it could be bled from both pipes. They both work well now as do the other 136.

The rads only have 1 quarter turn valve.

Charlie Tomkinson

We had a problem like that. We had to turn the water temperature up and replace the main pressure gauge which was giving a false reading.

John_54

The pressure seems alright 38 pounds and the temp is already up to 160 degrees.