Changed everything, bled everything, but still having circulation problems.

PoDuck

I have been in this building for 2 years now, and this is my third winter. I have a three zone hydronic baseboard system, and it worked okay for the first two winters. This year, I lit the pilot on the boiler, and flipped the switch, only to start hearing gurgling noises in the system. Not knowing much about hydronic systems, I figured that the water would come out of the air vents, and all would be good. Well, it wasn't. I then called a technician to come look at it, and he told me he needed to change out my pressure reducing valve, my air vents, and the pressure relief valve, and it would be about a full day labor for two guys, and quoted me a price that was way too high. Not having the money at the time, I told him I would have to wait a bit on it. In the mean time, I started looking at the prices of the parts. I could get them all for about 1/5 the price I was quoted, and none were terribly hard to change, so I decided to do it myself and save quite a bit of money. It took me about half an hour, all by myself. I'm pretty sure he was correct about the parts he claimed needed to be changed. I also decided to add drain valves to the return side of the zones so I could bleed the air out of the system better. That wasn't part of what the technician was going to do, but that took me about an hour to plumb, and didn't cost very much for parts.

Anyway, once I got all these things changed, I bleed the system, and turned it on. I no longer heard the gurgling I was hearing, but I wasn't getting warm water returning through the return side of things. I closed off all but one zone at a time, and still couldn't feel any warm water returning. I thought maybe I hadn't bleed things well enough, so I drained each zone for quite a while, even though I saw no evidence of air coming out. Still nothing. This suggested to me that my circulator may not be coming on. I tested that there was power going to the pump, and there was, but I couldn't see or hear any signs that water was circulating, so I got a new circulator and replaced the old one. I now get hot water on the return of two zones, but not on the third, and even the ones that are returning warm water are constantly calling. Also, not all the baseboards are getting warm on one of the zones that is returning warm water.

At this point, it seems that the only thing that could be the problem is that I still have air in all three zones somehow. This seems incredibly unlikely, given how long I let the water run through the zones when I bled them, but I don't know what else could be the problem. There are no bleeders on the baseboards that I can find, so the only place air can come out is from the 6 air vents that I replaced. I don't see water anywhere, so I doubt I have a leak that is letting air in.

What am I missing?

Edited to remove prices

george_42

each zone should have near the boiler, a shut off valve and a hose bib that you can connect a garden hose to. you must close all the shut offs and connect a hose to one of the hose bibs. then as you put water into the boiler you open the hose bib and let water and air out till you get only water .keep boiler pressure below 30 lbs throughout process. do each zone the same way till all air is out

Ironman

Please remove pricing; it’s against forum rules.

What type of piping system do you have? If you don’t know, posting pics of the boiler, it’s near piping and where the branches tee off of the main will help.

neilc

Are you pumping away from, or towards the expansion tank ?
Post one picture of the boiler, floor to ceiling, showing the boiler, circ(s), vents, and Ex Tank.

PoDuck

george_42 said:

each zone should have near the boiler, a shut off valve and a hose bib that you can connect a garden hose to. you must close all the shut offs and connect a hose to one of the hose bibs. then as you put water into the boiler you open the hose bib and let water and air out till you get only water .keep boiler pressure below 30 lbs throughout process. do each zone the same way till all air is out

Yes, I put a hose bib on each of the return lines coming back on the return from the boiler. I also followed that procedure to bleed the air.

Ironman said:

What type of piping system do you have? If you don’t know, posting pics of the boiler, it’s near piping and where the branches tee off of the main will help.

I'll get to pictures in a bit. It's been really busy here today with people trying to get all their stuff repaired before Thanksgiving. I'm not sure what you mean by piping system though.

neilc said:

Are you pumping away from, or towards the expansion tank ?
Post one picture of the boiler, floor to ceiling, showing the boiler, circ(s), vents, and Ex Tank.

The pump is pumping towards the boiler from the return side.

neilc

yah, not the boiler, the expansion or compression tank ?
the boiler only makes the heat,
the tank determines where the air goes, or comes from.
got that picture for us?

Gordy

What’s the system pressure, and what kind of expansion tank do you have?

System pressure should be 15 psi to get water all the way up to the top floor baseboards.

If the tank is in the ceiling joists there shouldn’t be any automatic air vents in the system.

Did you replace the circulator with same size?

leonz

If you have changed everything and bled everything and have nothing but water "it aint an air problem" as Dan would say.

We need to know if you have a steel compression tank in the ceiling joists above the boiler as It sounds like you do have a
cylindrical steel compression tank in the basement cieling joists and it is waterlogged and as result you have low or no heat.
We also need pictures of the piping to this tank and pictures of both ends of the tank as we need to know if it has a gauge glass as well

WE ALL need pictures of the boiler from all sides, pictures of all the valves around the boiler and in the ceiling, pictures of the controls with the covers off, pictures of the near boiler piping including all pipe connections and the circulator(s).

Once you know how to manage the air system for a steel compression tank and take care of it you will have lots of heat.

pecmsg

How much have you saved?

maybe get the tech back and pay to get it fixed properly!

GW

I’ve been bitten by the “no air and no flow” bug in the past, not fun, there’s always a reason. Good Heating guys can find the problem