Unusual problem with downstairs radiators

Discussion in 'Plumbers' Talk' started by Knackered1, Nov 23, 2021.

  1. Knackered1

    Knackered1 New Member

    A couple of years ago I had new radiators fitted downstairs - kitchen, hallway and living area. The old rads had both pipes going into one valve one end of the radiator. The new ones have a valve each end so additional piping was added. All of them get hot.
    The problem I have, if I turn off the kitchen radiator the other 2 go off as well. Same, if I turn off the hallway one the living area also goes off.
    I had a new boiler installed a couple of months ago going from a system boiler to a combi. Not sure why but was hoping this would resolve the issue.
    Can anyone tell me why this is happening? Do I need to open the lock shield valves or could the in and out flow pipes have been mixed up? I’m really stumped.
    Thanks in advance.
     
  2. Jiml86

    Jiml86 Screwfix Select

    Are those ones on there own loop if that makes sense?
     
  3. Knackered1

    Knackered1 New Member

    Unsure of that, sorry. I know that the hot water for the rads comes down from upstairs so at a guess I would say yes. The original system had the boiler in the kitchen which pumped and stored hot water in the loft. The upstairs all seems ok, those radiators were changed over quite a few years ago.
     
  4. Jiml86

    Jiml86 Screwfix Select

  5. Joe the Plumber

    Joe the Plumber Screwfix Select

    I wonder if the radiators have been piped up so the flow goes in one end and out at the other, but all on the same pipe, rather than in from the flow pipe and out to the return pipe.

    In effect then, each radiator becomes simply a "bulge" in a single piece of pipe with water flowing through it, with the last rad finally connected to the old return pipe.

    That's the only reason I can immediately think of for what you've described, but it would mean turning any valve off would stop the flow through all of them, so they would all fail to heat up.

    Sadly, I think some floorboards will need to come up to check the pipes.
     
    Hans_25 and Jiml86 like this.
  6. Knackered1

    Knackered1 New Member

    Thank you. The main run of downstairs pipes are under the concrete floor, only the couple of pipes that go into the radiator stick up out of it.
    Would an average central heating plumber be able to sort this out do you think?
     
  7. Joe the Plumber

    Joe the Plumber Screwfix Select

    Oh goodness. They might be able to. It's down to being able to work out the pipe runs and whether a mistake was made when the radiators
    were re-piped. It may be possible to sort out what's happening by turning off valves and then trying to bleed the rads to see if the flow
    can be worked out from that. I'm not feeling clever enough tonight to say exactly how I'm afraid.

    If the new radiator pipes were fitted just by digging up bits of the floor and connecting to the old pipes (8mm microbore I assume, as you had
    the twin pipe 'Yorkshire' valves previously?), it would have been possible to drop a clanger with them if they weren't completely exposed.

    For what it's worth, my own house has concrete floors and when I had a leak from one of the buried central heating pipes, I re-piped the lot above the floor by dropping new pipes down from upstairs.

    I think you will really need to get a plumber in. I'd suggest looking for an older one with a lot of experience, as it might well defeat a relative
    newcomer.

    Please keep us posted. It's a right nuisance for you, but a fascinating problem.
     
  8. Jiml86

    Jiml86 Screwfix Select

    Hi Joe,

    O.P stated that originally the rads had flow and return going into one valve. Could it be that the flow now goes through the radiators i.e the flow path is directly through rad 1 to rad 2 and so on and the additional pipework added is just the return from the last rad?
     
  9. dcox

    dcox Screwfix Select

    Sounds like an old one pipe system. When it's running, do you find the rads heat up one after the other rather than all warming up together?
     
  10. Joe the Plumber

    Joe the Plumber Screwfix Select

    Yes. I perhaps didn't explain it very well, but that's what I hope I said in my first reply, above.
     
  11. Joe the Plumber

    Joe the Plumber Screwfix Select

    I don't think it would be a one pipe system with the old double pipe Yorkshire valves the OP says were originally fitted. But you never know, of course.
     
  12. dcox

    dcox Screwfix Select

    I haven't come across those double valves. How do they work?
     
  13. Jiml86

    Jiml86 Screwfix Select

    Yeah pardon my ignorance i didn't fully understand. Thanks
     
    Joe the Plumber likes this.
  14. Knackered1

    Knackered1 New Member

    Hello. To explain a bit further, my old rads just had 2 pipes sticking up out the concrete floor going into the one valve. When changing the radiators and putting on new valves, the plumber just extended those two pipes with one now going into each end of the radiator. Could putting in one of those pipes into the wrong end of the radiator cause the problem?
     
  15. Knackered1

    Knackered1 New Member

    I used to be able to turn the radiator in the kitchen off while still having the one in the living room on but I can’t anymore.
     
  16. Joe the Plumber

    Joe the Plumber Screwfix Select

    They're these:



    If the plumber just extended the existing pipes above the floor, it should be okay, so perhaps there is another issue.

    The radiators are effectively just a big pipe, so in theory all they do is connect the two thin pipes together. It shouldn't matter which pipe goes into which end, but clearly something isn't right.

    Any chance of a photo of each rad with the pipework visible please?

    The only other thing is if the original flow pipe under the floor is blocked, so when you turn off the valve, the flow can't bypass that rad to get to the next one. As it's microbore, which is notorious for getting blocked, that's possible.
     
    Last edited: Nov 24, 2021
  17. Jimbo

    Jimbo Screwfix Select

  18. dcox

    dcox Screwfix Select

    thanks
     
    Joe the Plumber likes this.
  19. Knackered1

    Knackered1 New Member

    Hello. Thank you for your replies. I have taken photos of the 3 downstairs radiator pipes. I have noticed that the one in the kitchen has the pipes going in a different way. The tvr is on the different pipe to the other two rads. These are pipes from the kitchen radiator. I will do another reply to add photos of the others.

    DCBE4243-102B-4DED-8E69-CF91986E9673.jpeg AEE27D12-8232-4CA4-92DD-3ECDC260F2B0.jpeg
     
  20. Knackered1

    Knackered1 New Member

    These are the pipes on the other downstairs rads 9EA7AEFF-75DB-47DA-BB9A-821C64113F20.jpeg
     

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