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Heat going upstairs, but not downstairs AND now a wheezing from the boiler

noob Member Posts: 5
Hello. second time here at the forum. First experience here was great, so i'm back to try again.

This summer I converted a single zone radiant baseboard hot water system to dual zone -- up stairs and downstairs. Things seemed to be working fine until a pipe, (that I had not worked on), came loose. only about a 1/4 inch of the pipe had been seated in the elbow when it was sweated in. I don't know when that occurred, but it was more than 18 years ago (and most likely in the 1970's). This is for a tenants apartment that is attached to our house -- we share a basement. Anyway, I repaired the pipe. Seated it properly. Being a noob, I stuffed a bunch of bread up the elbow (a vertical member). Well, I couldn't get water to run through the system. Had to take it apart, and sure enough, I had a nice bread clog that I cleared out. Fixed that, but again, water was not running. Could feel a section of pipe where it was very warm on one side, and quite cool on the other, as if there was an obstruction there. I left it for the night, and when I came back in the morning, heat was flowing, so I assumed that whatever had obstructed the flow became dislodged and was now somewhere where it was not obstructing flow. But sure enough, a few days later, the heat was not flowing like it should. bled the radiators, could not discern any air problems. turned the unit off to give the boiler a chance to rest, turned it back on, and really, very little water flowing through downstairs run. Upstairs remains fine.
I turned off the upstairs zone to have water just go through downstairs run, but again, I could feel that no flow was going through the pipe. Indeed, when I close off the upstairs zone, turn off the new water feed to the boiler, and open up the run to let the downstairs run drain out, nothing comes out of the pipe, water is not moving. So i'm wondering if there is an obstruction somewhere along the downstairs run, and if so, what can I do.

So that's problem number one.

Problem number two is that the boiler itself is "wheezing" or "whistling" only when the boiler is firing. It is a Utica Boiler, circa 1970's I believe, 150AGB. I have googled "whistling boiler," and it seems to be a common problem. Note -- I have not had the boiler serviced in many years. I had a circulator pump replaced five or so years ago, but haven't had it serviced since then. Mostly because I was unsure as to what a technician would do during an annual service visit. One of the causes of whistling, from what I have read, is an obstruction in the boiler, perhaps from scaling or buildup. The water that had come out of the pipes was quite black when I did my work this summer, but is now pretty clear coming out. Also, the pressure readings seem to vary quite a bit.

I don't think the boiler wheezing is causing the first floor problem. I think there have been longstanding issues with the downstairs heat not working properly, even before I zoned it. I'm a decent landlord, so the tenants didn't complain when before the pipe burst, the temp WAS IN THE LOW 40's in the Apartment -- I had no idea !!!! Ive since been monitoring it and it never got above 64 (but that has to do with heat loss from old windows and very cold outside temps) As I type, it is now reading 56, up from 53 at 4:00 in the morning. Upstairs stays rock steady at the set point: 68.

Sorry for such a long post, wanted to be as thorough as I could be. I feel like the boiler wheezing is beyond my skill set, but the lack of flow downstairs really frustrates me.

Any thoughts are greatly appreciated.

Attached is a picture of that poorly joined pipe and one of the boiler specs


  • icesailor
    icesailor Member Posts: 7,265
    The first photo is of a 3/4" test cap. They only go in 1/2" to 3/8". What is supposed to be wrong with that?

    Never use bread or any temporary plugging device. You'll be sorry. As you found out.

    To get it out, learn to think like water and how it goes. Then, blow out the obstruction with compressed air.

    If the one zone worked well before you split it and now part of it doesn't work, you did something wrong.

    Think like water and figure it out. It might be easier for you to figure it out than some one off the street. No matter how experienced they might be. And you can always explain to them what the problems. Saves time and scratching.
  • Snowmelt
    Snowmelt Member Posts: 1,334
    Need pic of boiler pipping.