Hydronic Heating problems

Question

It seems to me like my main floor zone is circulating really slow. It take 2-3 hours to heat the main floor from 16-19. the supply pipe is crazy hot while the return i can hold my hand on comfortably. I did just have to replace the zone valve but it’s working correctly now. I had air problems that seemed to be coming from leaking bleed valves in the radiators but I fixed them, and bled the system.

The best I can come up with is maybe there’s a slight blockage in the system and the circulator is having a hard time getting by it, but I’m stuck on how to determine what it really is.

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Adam 2 years 5 Answers 423 views

Answers ( 5 )

  1. Yeah I hear ya but a blockage is the last thing I’m thinking. A failing pump could be it. But without being there it’s a little hard for me to say.

    But we really need to know what the pressure is in the system. Make sure sure the fresh water supply valve is open and that you leave it open. On the regulator there is a bypass switch. Open that up for like 15 seconds to let more water in. Where are you located?

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  3. The zone valve is opening, I check it manually every time I try to figure this problem out. I’ve bled the system several times the way you do in your videos into a bucket until no more air comes through. I wouldn’t think its air in the lines because I don’t hear the usual noises, and heat does eventually make it all the way through each radiator so it is circulating in some way.

    Half way through writing this I decided to bleed the lines again. There did seem to be some air in there, but another thing I noticed is when bleeding the lines with the pressure reducing valve closed, it empties into the bucket at little more than a trickle. I’m thinking more and more there is something lodged in a pipe or maybe a shutoff valve is not opening when it seems to be (failed rubber seal?)

    Also just turned on upstairs and downstairs heat at the same time. return pipes for upstairs were hot in a few minutes, main floor return still cold. Checking the radiators after 20 minutes, heat has almost reached the last one before the boiler.

    I’m pretty much convinced there’s a blockage, and its enough that the circulator┬ábarely gets by as they generate very little pressure if I remember correctly.

  4. I’m thinking the gauge is working but you don’t have enough pressure in the system for it to read, well maybe. You’ve a regulator after the city water so you should have that much pressure in the system. If you did the blow off would blow anyway.

    It really sounds like you have air in the system and or the zone valve is not opening.

  5. Well that’s a problem I only just noticed in the last few months. The pressure gauge doesn’t move at all lol. Somehting im gonna fix in the summer when I don’t have to worry about heat. It’s combination pressure /temp gauge on a kerr saturn, boiler is only around 5 years old. Temperature reads fine. I have checked the expansion tank and even opened up city supply to max out the pressure in the system (40psi) to see if that would help but no. The thing is, upstairs circulates perfectly fine.

  6. Most important question is, what is the PSI on the gauge?

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