Baseboard water heaters don't reach top level

nybigapple

3 story + basement building, with two apartments each floor, uses hot water baseboard heating. The pump was recently replaced from a B&G 100 pump, to a B&G NRF-36. The boiler was also replaced with the same model Weil Mclain. I was told the top floor has its own pump on the heating line. Initially both apartments on top floor did not have heat. Trying to bleed the top floor, one apartment was able to be partially bled, to restore heat. One apartment could not be bled at all.

How is that possible? Plumber said that the top floor needs a return line to the basement which it apparently doesn't have. He wants to drill down every floor to install that return line which seems wrong.

Ironman

Did the baseboards ever heat? If they did, then there must be a return line.
You probably don’t have sufficient static fill pressure for the height. It could also be improper pump location, but without being there to see it, it’s difficult to determine what’s exactly wrong.

nybigapple

Yes at one point they must have because this is a new complaint. It's possible I also misconstrued what the master plumber was saying. He said something about age, bad pipes, bad design with an additional pump inside the apartment, and ultimately needing a new return line. Possibly there is a return line that is no longer good? But he wants to install a return line as the solution to restore heat.

Jamie Hall

Far more likely that you simply don't have enough static pressure in the system. Particularly since you say that one apartment couldn't be bled at all -- which means that there isn't enough static pressure. An easy fix.

nybigapple

Can you talk more about what the fix would be? The NRF-36 is set to the highest setting. Shouldn't it provide more pressure than the old B&G 100?

Jamie Hall

The circulator pump has nothing to do with the static pressure. All it does is circulate the water -- as the name implies. Static pressure is the pressure in the system when the boiler is cold and everything is off, and is controlled by the expansion tank and, if there is a pressure reducing valve on the makeup water line, the setting of that valve.

The fix is to first determine what your static pressure needs to be, which is simply dividing the vertical distance, in feet, from the boiler to the highest point in the piping or radiators by 2.31. Then add 5. That will give you the required static pressure. Then isolate the expansion tank from the system and drain it completely, and add (or subtract it -- rarely) to match that figure. Then reconnect it to the system and add water with the makeup to reach that pressure with the system cold.

Now with a building that tall, you may find that when the system heats up the running pressure increases enough to approach the safety valve setting. In that case, the expansion tank either isn't big enough or has failed.

nybigapple

Thank you Jamie, I'm not qualified to do all that but knowing the process is extremely helpful. I think my master plumber should have known this and is possibly dishonest. I'll look into someone else about this.

Ironman

nybigapple said:

Thank you Jamie, I'm not qualified to do all that but knowing the process is extremely helpful. I think my master plumber should have known this and is possibly dishonest. I'll look into someone else about this.

He could simply be incompetent which is just another side of dishonesty.

neilc

can we post a picture of the boiler, and of the pressure gage there?

Rich_49

nybigapple said:

Thank you Jamie, I'm not qualified to do all that but knowing the process is extremely helpful. I think my master plumber should have known this and is possibly dishonest. I'll look into someone else about this.

A master plumber is a plumber , not all plumbers are qualified to work on heating systems or even know WTH they are looking at