No flow from concealed shower valve

Discussion in 'Plumbers' Talk' started by AaronHarvey, Dec 10, 2020.

  1. AaronHarvey

    AaronHarvey New Member

    We can't seem to get any flow from our shower valve. Now when this was installed in August it worked perfectly with no issues. Gradually over time it has become increasingly more difficult to start, in that it would take a moment or two for water to flow or the flow to be enough to kick the pump in. Found we would have to shake the hose a bit or lower the shower head into the bath to help get it going. I assumed that we were getting airlocks in the system?

    Its now completely stopped. Can't seem to get any water flow even if I bypass the pump by turning it off. There's not even a dribble. The only way I've found to get any water flow is to turn the temperature perhaps beyond where it should on the cold side then water flows but still not enough to activate the pump and will immediately cut off as soon as I begin to turn the temperature up as if its the flow controller rather than temperature.

    Figured there might be a blockage or a faulty thermostat cartridge? I've only had time to remove the hot water check valve filter so far and that seems clean?

    Any advice please?

    Thanks in advance
     
  2. terrymac

    terrymac Screwfix Select

    Non return valve/s sticking is a possibility.
     
  3. ??? Really?
     
  4. What shower pump do you have?
     
  5. terrymac

    terrymac Screwfix Select

    Yes really. Low pressure gravity flow required to trigger the pump. Not enough pressure to open the valve,no water flows through shower valve and pump won't start. Fitted a shower valve few weeks back ,brand new ,NR valve stuck solid ,couldn't even push it open with a screwdriver !! Customer returned it to retailer for a different brand as no confidence in a direct swap.
    May not be OP's problem ,but a possibility.
     
  6. AaronHarvey

    AaronHarvey New Member

    Anyway to test this? Does this explain the problem happening gradually over time?

    As I said, when first installed we had 0 issues.
     
  7. terrymac

    terrymac Screwfix Select

    Not familiar with your valve ,but most have a filter and non return valve on or close to the inlet ports. So isolating water supplies and part stripping of the shower valve is required to access them. Then once revealed it's pretty obvious to see how easily the NRV can be pushed to open. It is only the water pressure in your gravity fed supply that pushes it open and allows water to flow into and out of the shower valve. Once water flows ,the pump flow switch activates the pump.
     
    Last edited: Dec 11, 2020
  8. AaronHarvey

    AaronHarvey New Member

    Seems like the valves are stuck. When removed and the isolation feed supplying the shower valve are turned back on the water runs. Would these have become stuck in time because the flow/pressure to the shower valve has been too poor?

    Screenshot_20201211-181123_Gallery.jpg
    Screenshot_20201211-181118_Gallery.jpg

    The pipe work needs amending to improve the flow to the valve and pump. This is how it is currently fed. The isolation valves need replacing for full bore valves. Would it be best to install a Surrey flange to the top of the tank as well as the AGL.

    Would it also not be best for the cold feed to have an elbow or bend directly across to the pump rather than going down then back up again?

    Screenshot_20201211-181646_Gallery.jpg
     
  9. terrymac

    terrymac Screwfix Select

    You do realise that the NRV only opens one way ,allowing water into the shower valve ?
    How easy or difficult was it to push them open ?
     
  10. AaronHarvey

    AaronHarvey New Member


    Yeah yeah, I get that. Not sure how I can force these open without ruining the filter mesh at the bottom.

    There doesn't seem to much if any movement on it at all. How much do these usually move when they open up?

    Screenshot_20201211-184733_Gallery.jpg
     
  11. terrymac

    terrymac Screwfix Select

    Can't work out the orientation for certain ,does in coming water from supply go through the filter before reaching the NRV ? They don't move much ,a few mm.
     
  12. terrymac

    terrymac Screwfix Select

    Does the filter unscrew with a large hexagonal wrench( Allen key) ?
     
  13. AaronHarvey

    AaronHarvey New Member

    Yeah incoming water goes through the filter before the NRV.

    It looks like it should unscrew but also looks like the two halves of the brass casing have been sealed together? Or would this just be some plumbers mate or similar? You can see the seal in the first couple of images I sent.
     
  14. terrymac

    terrymac Screwfix Select

    Ha , thought that ring was limescale !!
    If you blow thru the filter you should hear / see the NRV open,feel air flowing thru.
     
  15. AaronHarvey

    AaronHarvey New Member

    Definitely no air going through there
     
  16. terrymac

    terrymac Screwfix Select

    And is that the same on both hot and cold ?
    You need to blow quite hard thru the filter,preferably with it sealed around your lips,if that doesn't open the NRV it must be stuck .
     
  17. AaronHarvey

    AaronHarvey New Member

    Ok so just got the cold inlet valve off. Filter was little blocked but cleaned it up and the NRV does move, tested by blowing through it.

    Valve on the hot inlet is definitely stuck, although the filter was clean when removed.

    So hopefully this is all the problem is.

    What would cause the valve to stick?
     
  18. terrymac

    terrymac Screwfix Select

    Obviously if no water can get past it that's your problem. Causes.....Limescale , grit, dodgy manufacturing quality, impurities in water supply not caught by the filter.
    With regard to your installation photos ,although it's not the simplest way to have set it up ,it did work fine for months so It's not really worth changing except the isolation valves for full bore. You need to have the full benefit of the gravity flow .
    You should also check the shower heads ,the holes in them can block up and restrict flow.
     
  19. AaronHarvey

    AaronHarvey New Member

    All sorted, cheers bud.

    Removed the faulty NRV completely for now. (Just the white plastic insert and refit the brass casing and filter). Have a new one on order.

    One other issue is the temperature control seems a little stiff when turing to cold, and changing the temperature seems to fluctuate the flow.

    Could this be the result of only 1 NRV being present or a faulty thermostatic cartridge?
     
  20. terrymac

    terrymac Screwfix Select

    I wouldn't think removing the NRV could have any bearing on the temperature control being stiff. Could you have possibly done something not quite right whilst taking things apart , particularly relating to the temp control / it's handle ?
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice