Some radiators not working

Jmassaro21

I just bought a house with a hot water boiler system with radiators and baseboard heating, 2 zones. Some of the radiators in the larger zone have stopped working and I’m not quite sure how to try to fix this myself. Any help would be greatly appreciated, as I have not been able to find videos online that look like my radiators. Here are some pictures 

JUGHNE

What you shown are cabinet hot water convectors. Probably older than the baseboard system. If so I would guess the large red pump runs the water thru the old units. Does it run when the tstat calls for heat?

The other small green pump in much newer and maybe does the BB heaters.
You may not hear it run, only feel the motor or put the tip of a screwdriver on the pump and the handle pushed into your ear, you should hear the pump/motor.

Jmassaro21

Ok thanks, it seems like the red pump is not working, I do not see and/or hear anything coming from it, and the pipe coming out of it does not get hot when the tstat calls for heat, while the other pipes are getting hot. Does that mean I just have to replace that pump? It’s a bell and gossett 1/12 HP pump 1725 rpm

mattmia2

It could be the thermostat or other controls as well.

How is the boiler set up, does it always stay hot or does it fore on a call from one of the thermostats? You would want to try jumpering the terminals where the thermostat for that zone connects and see if it heats that way. if that doesn't run the circulator, check to see if there is 120v to the circulator. If there is 120v to the circulator you can replace it with a modern circulator, if no 120v then you need to troubleshoot the controls.

Jmassaro21

When I first bought the house, one of the convectors didn’t work, but towards the end of last winter a few more stopped working. Do you think it could still be the thermostat even if some of the convectors were previously working?

mattmia2

If the circulator isn't running then they won't heat or won't heat very well.

Are the convectors and the baseboards on different zones or are they intermixed?

I'm not convinced the older style circulator is necessarily for the older convectors, the newer circulator may simply be a replacement from after that older boiler was installed.

What is that puddle in front of the boiler?

It i suppose could be a slowly failing circulator or it could be air or a few other things.

Jmassaro21

They are intermixed. One zone has convectors and baseboards, and the other zone just has baseboards

bburd

@op What is the pressure / altitude reading on the boiler gauge during a call for heat, and when the system is cold?

How many stories is the house?

Jmassaro21

It’s not a puddle, it’s some paint that peeled off the floor in that area. 

This is a small ranch home, so one floor with the boiler in the basement. 

Here are the gauge readings while cold, and then running after 10 min 

Ironman

Assuming the gauge is reading correctly, the minimum cold pressure should be 12 psi. Your fill valve may be faulty or improperly set.

The red B&G series 100 pump is three piece construction and you can easily see if the coupling is spinning in the mid section.

Jmassaro21

Thanks, so it seems like I could have two issues, a faulty fill valve plus a faulty pump. Are these easily fixed ?

Jamie Hall

And assuming that the gauge is reading correctly, not only may the fill valve be faulty -- but if it really is at or close to zero cold, it may be pulling air in on some of the radiators, which may leave them airbound.

I'd also be very suspicious of the condition of the expansion tank...

Ironman

Jmassaro21 said:

Thanks, so it seems like I could have two issues, a faulty fill valve plus a faulty pump. Are these easily fixed ?

That would depend upon who’s doing the fixing.

mattmia2

With that low a cold fill pressure it is probably pulling air in through the automatic vents on the highest emitters.

The pressure reducing valve(prv) should be keeping the system filled. It is that thing with the bail handle on the top to left of the green circulator. Make sure the manual valve before it is turned on (and any valve that might be between it and the boiler). It is poosible someone tuned it off a few years ago while servicing something and forgot to turn it back on and it just became a problem now. If that doesn't work, try pulling up on the handle on the prv and see if water starts flowing and bring it up to 12 psi on the gauge. You can also do it with a washing machine hose connected to one of the drains if the prv is bad. You will need to keep adding more water as the air bleeds out of the automatic vents. the cap on the automatic vents needs to be loose for them to vent air. Check them once you get the system filled to make sure they aren't leaking.

Once you get the system filled, check the pressure once it heats up, make sure it stays under 25 psi or so when it is hot, if it goes higher than that you have some sort of expansion tank issue.


Check the pressure a couple times the forst day then daily for the next week or so to make sure it doesn't fall again. If you manually filled it, you will have to fill it more as the dissolved air comes out of the fresh water.

Look carefully around the system for leaks ince yo get it filled. There may be a new leak or it may have just leaked slowly in minute and benign quantities around valve packings and the pump seal over a couple years.

Jmassaro21

I followed the steps to add water back to the system and increase the cold pressure to 12psi which worked, but when I called for heat, certain radiators still did not work. So I’m guessing the circulator pump is the problem? Should I replace the B&G one?

mattmia2

Did it stay at or above 12 psi once you started it? Are the caps on the automatic air vents open? Some of the automatic vents could also be bad or there may be manual vents on some convectors or baseboards.

The circulator could be bad but it is much more likely there is still enough air in the system from the lack of pressure to stop circulation.