Messy existing central heating install - advice needed

Discussion in 'Engineers' Talk' started by damtomuk, Nov 8, 2022.

  1. damtomuk

    damtomuk Member

    Hi all.

    I uploaded picture to explain better this messy installation. There is a problem with two downstairs radiators in lounge and hallway. They are brand new with new valves and been changed not by me and they are not getting hot at all. There is mixture of one pipe system and two pipe system. All radiator upstairs are getting very hot. If i shut master bedroom radiator down, i am getting hot water just before downstairs TRVs and few panels of downstairs radiators are getting luke warm. If i open master bedroom valve, i am not getting any heat downstairs. Original grundfos circulation pump UPS15-50 failed few days ago , and it was replaced. There is good flow from trv and Lsv downstairs once radiators are removed. It looks like there is issue with circulation to downstairs.

    I am thinking of cutting 22mm pipes from bath radiator tee them and extend them to downstairs radiators and leave master bedroom on its own 15mm loop or would stronger pump would do a trick , like ups25-60?

    It is heat only boiler


    Attached Files:

  2. Abbadon2001

    Abbadon2001 Screwfix Select

    To me, that 1 pipe system is a "plumbing atrocity" which cant surely work at all? the water will take path of least resistance - i.e. it wont flow in those radiators the way that diagram shows they are plumbed? Do you really mean the rad has both in and out on the flow pipe, and it has a bypass also? because that simply wont work....
    damtomuk and Hans_25 like this.
  3. Hans_25

    Hans_25 Screwfix Select

    You need to get rid of the upstairs 1 pipe system and plumb it properly, the hot water is going round these pipes as its the path of least resistance, and so not going to the downstairs rads. Hence the problem is actually upstairs, not downstairs.
    Kingscurate, damtomuk and Abbadon2001 like this.
  4. Abbadon2001

    Abbadon2001 Screwfix Select

    Exactly this.
    Kingscurate and damtomuk like this.
  5. damtomuk

    damtomuk Member

    Thats correct, sorry i didn't take picture of rads, house was bought few months ago during summer , now came colder days and radiators downstairs are not working at all. Surprising one pipe radiators are getting very hot and bath rad two , master bed hot but not as hot as others
  6. damtomuk

    damtomuk Member

    Totally agree with you, least resistance, unfortunately upstairs will be done after winter when bedrooms upstairs will go under renovation. Meaning that i have access to bath rad piping , should i extended to downstairs rads ?
  7. Mike83

    Mike83 Screwfix Select

    I would fit a gate valve on the one pipe system. Use this and throttle down the supply.
    This may help with circulation on the 2 pipe side.
    You could even close the gate valve completely initially and make sure the 2 pipe side does in fact function correctly.
    Abbadon2001 and damtomuk like this.
  8. damtomuk

    damtomuk Member

    What i did , i trimmed down LSV to minimum on one pipe radiators but oddly still there wasn't enough flow to downstairs radiators
  9. Mike83

    Mike83 Screwfix Select

    Even if you turn all the radiators off on the one pipe circuit the water will still flow around the loop.
    This will cause issues.
    Abbadon2001 likes this.
  10. Bob Rathbone

    Bob Rathbone Screwfix Select

    Consider a re install of the pipework in a more planned and considered manner. Start with the parts you are going to have access to and during this time allow for the radiators in other rooms to be connected, maybe tee off and run the pipes through the ceiling and cap them temporally. Needs planning and foresight.
    Kingscurate likes this.

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