baseboard stays cold

jjnyc · October 2013

I m at a house trying to figure out why 2 baseboards on the third floor wont get hot. . There are 3 baseboards, fed by three seperate supply and return risers. One works perfectlywhile the other 2 wont heat. Ive bled them both out and one will heat up slightly then cool down while the other wont get past lukewarm no matter what i do and ends up cooling down. I checked every radiator beneath and theyre working fine. I changed the circulator pump(return side) because the previous one was dead and i added a spirovent near the supply side of the boiler. The only thing i noticed there was no check valve on the return side. Oh ya, the whole system is one zone as well. Is the lack of a check valve on the return causing circulation problems for the 2 cold baseboards? Any help is appreciated. Thanks

JohnNY · October 2013

possible

Bad piping? Not enough pump?

STEVEusaPA · October 2013

Nothing to do with check valves...

Did it ever work right? Were any modifications made? When you changed the circ, are you sure you picked the right one.? What size pipes, etc. etc.?

More importantly....mono-flo fittings? In other words, why would the water want to go there, or why would it not?

Hard to diagnose without spending some time with the system.

RJ_4 · October 2013

air

If the system worked before you may have some air in system, any time work is done on hydronic systems air will get back in system after refilling, are you bleeding at highest point and for how long, are you bleeding with pump off, do you have purge valves for zones

jjnyc · October 2013

troubles

There are no mono flo fittings from what I've seen during the renovation, just 1 1/2 black tees branching off to the units on each floor. I assume they are being fed by 1" copper lines as thats all I see leaving the boiler room.

I replaced the existing pump with an identical pump (a taco 007) so I dont know if it's the proper one.

During the reno phase last year when I tapped into the existing supply and return risers to rough out the pex lines for the future baseboards, they did not immediately get hot after I was bleeding them, but they eventually did when I came back a few days later. Thats as far as I know if they ever worked.

I installed a ball valve with a bleeder tee so I could try to isolate the two lines as I bled them. That didnt seem to work when I was bleeding them last night as I kept on getting luke warm water that would eventually cool down.

I also noticed that as I was bleeding the living room radiator, some air would come out, followed by water. The pressure of the water would gradually decrease until nothing came out. Then, after a minute or so, the water would come back. and this cycle kept on happening over and over. The baseboard on the floor beneath that is being fed by these risers has no problems whatsoever and is working excellently.

The piping is real spaghetti throughout the house and is far from ideal. it seems like the previous owners just kept patching it up. thanks for the help.

RJ_4 · October 2013

air

When bleeding air from a system which can travel throughout the system you need to keep system press. up, this may require partially opening fast fill valve if you have one or introducing another water source other than the prv. As far as the piping the pump is a ( differential machine ) if your piping is not installed or balanced correctly your pump cant cause a differential and a no or per flow condition will exist

baseboard stays cold

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