Hot water radiators not getting hot...Everything seems to be working fine. 2 story home. Airlock?

OSU496

Came down to get things rolling this year and oiled everything before turning on the system and the pump was barely spinning the coupler. Replaced the bearing assembly and put the old impeller (impeller looked fine) on the new assembly attached to the old motor and now the pump is running smoothly. However...the radiators on the 1st or 2nd floor are not getting hot.

Water coming out of the boiler is piping hot and boiler seems to be functioning fine at 15 psi. We think that an airlock may be the issue but I have bled each radiator throughout the house and just got water out of them? Thoughts??

UPDATE: I don't know much about the expansion tank but there is a pipe running from the return to the tank and below that there is a valve that says Air Charge this way.....Operating other way. Not sure what this means but originally I thought this would take the air out of the system so I opened it up and got A LOT of air out. This in turn has filled the expansion tank up with really hot water??

Thanks!

nicholas bonham-carter

If that is the old style expansion tank, it will need to be emptied of water, so as to reestablish the air cushion. Does this valve have a Schrader valve such as on tires to pump air in?
Check and see if there is a valve which has been closed on the lines leading upstairs.—NBC

OSU496

No Schrader valve. I have included pictures of the valve and piping down there. I did not drain any more water out of the valve but the tank is about half full now. I’m assuming the boiler took the extra water? There is no shut off closed going upstairs. A boiler professional we know has told us to get to the closest radiator and then let cold water run out until we get hot water...

Pictures below:

Jamie Hall

That air tank has been there awhile... is there a sight glass on one end of it? If there is, it should show the water level as being roughly half full. There may also be a float or other type of valve which will release air if the air volume is too great. There may also be a valve which releases of the air pressure is too great.

There must NOT be an air eliminator anywhere on the system.

OSU496

Jamie,
There is not a sight glass on the end of it. After trying to bleed some more and getting a little more than luke warm heat out of the downstairs (and one upstairs) radiators it seems as if the expansion tank is about half full now.

The first floor and one radiator upstairs are now heating up and getting hot water (although not NEARLY as hot as they should be w/ T-Stat on 80 F) but after 2 hours or so they go back to cold but the pump is still running.

UPDATE: Noticed that the pressure on the system is at 10 PSI...this is a 2 story home. How do I add pressure to the system??? I have read to add water, but the incoming water valve from the city is always open?

Thanks again!

JUGHNE

Did you remove the pump body out of the piping/flanges?
If so is the arrow pointing the same way it was?

It looks like you should be pushing water into the boiler.

OSU496

Yes...the entire pump and motor was taken off the flanges. We replaced the bearing assembly and put the old pump on the end of the new bearing assembly.

The pump body arrow is pointing up like it was before...

Side Question: Can you purge air out of the system through the relief valve on the boiler? Even after I bled all of the radiators I had pipes rattling like crazy so I did this and got A LOT of steam and air before water came out...

OSU496

There is a continuous feed into the boiler...how do I push water into the boiler???

JUGHNE

Your hot pipe out of the boiler is on the upper left on that side of the boiler…..the return into the boiler is lower right...yes??

So just a wild guess here....

With the arrow pointing up, the direction of the water flow, BTY, you are pulling the water out of the lower part of the boiler.

You have an extra pump body on the shelf there. Study the in and out. The inlet has the big bulge on the back of the body.

Let us know....it has happened before.

JUGHNE

Was this problem resolved?

HVACNUT

Is it a mono flo system?
Perimeter loop with 2 branches to each radiator?

If so, and if the returns are getting hot, you'll need to bleed each individual radiator.

I dont know why you spent time and money on a B.A. when you could've just dropped the pressure to 0 and replaced the whole thing with a new wet rotor pump.
Unless the bolts needed a visit from the sawzall, it would've been much easier.

JUGHNE

He has not been back. I wonder if he flipped the pump body and it fixed things? I am curious to know if that was the problem.

I called that out on one other posting in the past and that OP did reply that that was the case.