Screeching mixer shower

Discussion in 'Plumbers' Talk' started by goingroundincircles, Jul 13, 2014.

  1. goingroundincircles

    goingroundincircles New Member

    Mira Acquations mixer shower linked to mains water and worcester bosch combi boiler. Both installed together 10 years ago.
    Shower recently started screeching . Mira suggested getting mains water pressure checked before servicing shower.
    Utilities company confirmed all ok with water pressure and water flow. Water pressure was 5 bar static and waterflow 23 litres. Pressure will not go above these readings due to nature of supply. There has been no change in the water pressure in recent months and all households in the area on similar pressure and flow readings.
    Mira confirmed readings were within their specification.
    Mira engineer called out - could not find a fault with the shower, but changed the flow cartridge anyway, but this did not make any difference. Suggested installing a prv set at 2.5 bar
    I have not taken Mira's advice yet. Puzzled as to why the shower might start to screech when no change in mains pressure and flow and shower worked ok for 10 years.
    Any ideas?
     
  2. Phil the Paver

    Phil the Paver Screwfix Select

    Does the shower have isolating valves on the pipe work.

    Only asking because I had a cold tap in the bathroom that started screeching, when I was having a look at it, I turned the valve off and was just about to take the tap apart, when someone in the house wanted to use the sink, so turned the valve back on for them and no more screeching???, I can only figure that maybe it had some scale on it reducing the flow or something, but to date it hasn't made a murmur.:)
     
  3. goingroundincircles

    goingroundincircles New Member

     
  4. goingroundincircles

    goingroundincircles New Member

    Hi Phil

    No isolation valves as far as I am aware
    No limescale. Water quality is good.

    I did call out a plumber a few months ago to lubricate and tighten up the stop cock gland under kitchen sink a few months ago. I was away for a couple of months and had to turn my water off at the stop cock for insurance reasons. When I returned home and switched the water back on the stop tap was dripping hence the plumber call out. That is the only thing that has changed
     
  5. elefantman

    elefantman Member

    Try turning the stop tap down a touch to see if its a flow rate thing, if you've got a water flow guage check the dhw is matched to boiler recommendations, also check for a non return valve on boiler supply they can fail and make this type of noise
     
    Plumberbish likes this.
  6. goingroundincircles

    goingroundincircles New Member

    Hi elefantman

    Already tried turning the stop tap down - no change.
    Not got a water flow guage but utilities company took the water flow rate which was 23 litres per min. Dynamic pressure at 1 bar produced a reading of 25 litres per min.

    When we had the boiler serviced in Jan the service report read 20 litres. The boilers min operating pressure is 1 bar and the flow rate 17 litres per min.

    Thanks for your advice to check non return valve on boiler. When the boiler is serviced again I will ask engineers to check this out for me.

    If any forum members are reading my posts I am still open to any suggestions
     
  7. Biochef

    Biochef Member

    Try turning on cold tap in bathroom if that's where your shower is and listen to screech if it stops then you can fit an isolating valve to cold inlet to shower I recon if you turned down at mains then same in balance is present Only at a reduced flow try one of these
    image.jpg
     
  8. Biochef

    Biochef Member

    Try turning on cold tap and see if it stops screeching if it does then you could try and fit a full bore isolating valve to cold inlet to shower and reduce flow slightly
    You said you already reduced at stop cock but I recon the same in balance was there only at a reduced flow try one of these on cold feed to shower image.jpg
     
  9. goingroundincircles

    goingroundincircles New Member

    thanks biochef - appreciate your advice
     
  10. CraigMcK

    CraigMcK Screwfix Select

    Try turning down the boiler water temp. We have a similar sounding issue. When the valve struggles to shut down the hot water enough to get a cold shower. Do you get the same noise if you turn the temp to maximum on the shower?
     
  11. elefantman

    elefantman Member

    Hi if your flow rate is 23lpm through the dhw tap via your combi and the manufacturer states 17lpm then it's over pressured, either restrict the flow through the boiler at the diverter or on the inlet valve,I'd be tempted to reduce the whole water pressure on the stop tap first measuring at dhw full flow at the furtherest point from supply (usually the bath) if the pressure fluctuates consider a govenor on inlet pipework, having the correct flow will increase efficiency and usually stops hammer and other supply noises, in this case more is not always better.
     
  12. Sean_ork

    Sean_ork Screwfix Select

    welcome back Mr Elefantman (genuinely)
     
  13. elefantman

    elefantman Member

    Haha I'm away in the camper, free wifi and no tv means a cheeky return, I've read your posts, good man!
     
  14. Sean_ork

    Sean_ork Screwfix Select

    anywhere nice ?
     
  15. elefantman

    elefantman Member

    Aberdaron wales it's a favourite, well off the beaten track, there's money here though judging by all the new solar pv that's being fitted
     
  16. Sean_ork

    Sean_ork Screwfix Select

    very nice - the really wise folks fitted theirs a while back ;)
     
  17. goingroundincircles

    goingroundincircles New Member

    Have recently had a PRV installed. Unfortunately, my tenant reports that there is still a screeching noise. Before the PRV was fitted I visited the propety and noticed that there was no problem when the shower was running on cold only. The problem was apparent when a hot was introduced. I would describe it as a 'rush of water' follwed by loud screeching. Since the PRV was fitted my tenant says there has been some improvement. When the mixer shower is on a very hot setting it doesn't seem to bad. When it is on a cooler setting the noise is loud.

    Since July there have been a bouple of boiler breakdowns. The second being a faulty flow switch which was replaced. My tenant reported that the noise problem was worse when the boiler was repaired.

    As I have already paid for Mira to check the shower when no problem was identified and flow cartridge automatically replaced and have PRV fitted and boiler has been regulary serviced and repaired I am struggling to know where to go next. I contacted the guy who fitted the brand new central heating system and boiler 10 years ago and he has suggested our tenants check for boiler noise as there may be a problem with the heat exchanger. I have asked my tenants to keep an accurate log of day, time of shower and symptoms of shower and boiler.

    Does anyone else have any ideas?
     
  18. goingroundincircles

    goingroundincircles New Member

    Problem solved! Mira were called back to check shower again. The engineer was still at a loss as to what was causing the screeching noise but as I had had a PRV fitted on their recommendation and had the boiler checked Mira agreed for the engineerto return again with other parts to try.

    He returned and fitted a new thermostatic cartridge and the screeching noise has now gone.

    Whilst I am pleased that Mira agreed to return at no extra cost -having already charged me a £165 fixed fee I am disappointed that they insisted on me have a PRV fitted before exhausting their own checks. It has taken a long time to resolve the problem and I am out of pocket by about £100 for unnecessary PRV - Mira have refused to refund theis unnecessary cost despite it being on their recommendation.
     

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