Radiator issue - Only comes on when others off

LBF21

Lads - Having an issue with the radiator in the sitting room. It is the last in the line of 12 radiators and does not come on unless the radiator in the bedroom above is off. I could have the heating on for an hour and nothing then turn down radiator upstairs then immediately the sitting room one blasts on.. I've had 2 plumbers out who have balanced the system but still the same issue persists. I am thinking it might be the circulator pump is not strong enough for the system. The pump is a 6 valve Evosta 2. We had a large vertical rad added during the year too. Also just to note when I turn upstairs and sitting room kicks I can then go back up and turn on the heating in the bedroom.

Thoughts, new more powerful pump?

Thanks

Wearb

Sounds like a balancing problem, but if youve had 2 plumbers out there's not much point in going further down that path.

Maybe a work around would be to put a programmable thermastatic head on that valve and time it to come on after the downstairs one has kicked in. You can also get rad valves that can be controlled by wifi or bluetooth.

10-10-20

https://www.boards.ie/discussion/comment/120084862#Comment_120084862

Actually, in that same vein - do you have any TRV's on the rads, OP? I was thinking that if you had they should be closing off rads in rooms as they heat up and the pressure to that last rad should be fine at that point, but if you already have TRV's and it's still the same - then I'd wonder how that upstairs rad was plumbed in. Do you know if it was a retro-fit?

LBF21

thanks both. Yes have TRV's on all rads. We're only in the house less than a year. It's about 20 years, Not a retro fit. I already have Tado in so might just add some smart TRV's. I was going to do this eventually as a bit of project. It just seems like there is too much on the system.

DublinDilbert

As per above with balancing, i would wind back the supply to the two rads above and see how that helps. It may also be an air lock, that it is just getting a trickle of water, had similar before. I just turned off all other zones/rads and forced water into the one with the issue, lots of gurgling and the issue was sorted. I did need to top up the water in the system and bleed the rads.

LBF21

https://www.boards.ie/discussion/comment/120087524#Comment_120087524

thanks tried that with all radiators off apart from sitting room and it comes on flying but reverts to same when upstairs bedroom on. Absolutely headwrecking.

FlipperThePriest

https://www.boards.ie/discussion/comment/120087695#Comment_120087695

We had a somewhat similar issue with a rad in the kitchen. This is a kitchen rad that replaced a range stove that was taken out. Because of the way the range was plumbed (up to the attic and back down) the rad wasn't getting sufficiently heated unless other rads were off, and there was airlock issues too. The plumber solved it by putting a second pump on that line, but before he did so, a work-around for us: we have a remote climote thermostat, TRVs on all rads, so we just moved the stat into the kitchen and when all other rooms were sufficiently heated, TRVs would turn hot water to other rooms off, allowing hot water last but not least get to the kitchen. Not ideal, obviously dependent on a remote stat.

LBF21

found what the issue was by accident last week. Water pressure was too low. Once I topped it up, the rad was grand!

Wearb

https://www.boards.ie/discussion/comment/120238267#Comment_120238267

Speaks volumes of the ability and diligence of your 2 plumbers. 🤪