5/26 radiators don’t work

I’m now in a new to me house. The house is 20 years old.  The heating system is odd and there are various thermostats for different parts of the large house and the piping is white poly pipes and not copper pipes. 

Anyway, most of the radiators on the bedroom floor don’t work.  One does, and it’s turned on when loft heaters are on, but none of the others work. However, I recently tried to isolate them and I’ve managed now to get one to work.  I’ve bled them and do so regularly and a number of those, on other floors (that do work) don’t really fully heat up. 

I’ve had four GasSafe heating and plumbing engineers and none really know what’s happening. 

Any thoughts?


  • Jonboy_1984
    Jonboy_1984 Posts: 1,187
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    What model boiler is it, how old is it, and how big (long) are the radiators?
  • ThisIsWeird
    ThisIsWeird Posts: 4,458
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    edited 13 November 2023 at 7:14AM
    "Various thermostats for different parts of the large house..." - could you explain fully, please.
    Ie, "ground floor has the following rooms, and has this wall stat in this room...", ideally with a pic of the stat.
    Repeat for all floors.
    Also a photo of the main 'plumbing' area - I'm guessing you must have a hot cylinder somewhere, and likely it'll be surrounded by the motorised valves and connection boxes that control the whole thing.
  • markin
    markin Posts: 3,717
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    What steps did the gas engineers actually do?

    The simplest problems are stuck TRV,,'s, stuck motorised vales or unbalanced and the water takes the easy route.

    is the water clean looking?
  • FreeBear
    FreeBear Posts: 14,224
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    markin said: The simplest problems are stuck TRV,,'s, stuck motorised vales or unbalanced and the water takes the easy route.
    With multiple thermostats, it sounds like a zoned heating system. So I would go for a stuck/faulty motorised (zone) valve somewhere. Hopefully, who ever installed the heating system put all the zone valves in a central accessible location - First step (after locating the valves) is to see if the little levers on the side can be moved manually. If not, the valve may have seized up and needs replacing.

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  • tacpot12
    tacpot12 Posts: 7,831
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    Does the title of your thread mean that five out of 26 radiators aren't working? If so, this is a very large house with a very large heating requirement. As well as the more traditional problems that occur with heating systems, I suspect that such a large system might have more than its fair share of problems, especially if it has been installed by engineers that only deal with residential systems. You might be better off with a plumber that deals with commercial systems if it have 26 radiators. 
    The comments I post are my personal opinion. While I try to check everything is correct before posting, I can and do make mistakes, so always try to check official information sources before relying on my posts.
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