Hi, 1st time posting to DIYnot and I've searched the Wiki with no luck so apologies if this has already been covered elsewhere (and if so could you point me in the right direction - ta).
I have recently refurbished our en suite and am having a problem with the thermostatic bar mixer shower. When turned on, the pressure in the shower oscilates from good to poor and back again (at about 3 second intervals). I've found that if I remove the shower head tube from the mixer unit and let the shower run for 10 or 20 seconds this seems to fix the problem, but would rather not have to do this each morning. From elsewhere, it read that it could be air in the pipes causing this but unsure as to how to confirm / eliminate this.
Briefly, it's a gravity fed system. CW tank in loft, HW cylinder on same floor as shower. 15mm pipework running from respective tanks (i.e. up from HW cylinder) across loft joists and then drops down to the back of the shower which is a thermostatic mixer.
When I've run the water straight form the mixer unit and re-connect the hose the pressure is absolutely fine (not bad considering that the vertical measurement from the bottom of the CW tank to the shower head is approx 1m giving a mighty 0.1 bar pressure!) so I'd rather not go down the new system route (i.e. unvented) or install pump (little one on way and don't want the noise etc), plus another shower in the main bathroom works fine off the same system (but isn't a mixer shower).
One thing I've tried was to increase the HW tank temperature from 65oC to 70oC as I read that the thermostatic mixers like a hotter input - either way, this didn't work other than to ensure that I had a lovely hot shower (following the 'mixer drain' fix - clearly). Another thing I'm going to try tonight is to look at the mains / ballcock feed onto the CW tank in the loft, my logic being that if this has crusted up (limescale) then when the shower is on, cold water may be being used up at a more substantial rate than is being refilled, and therefore there is reducing levels in the CW tank producing less pressure in the HW tank meaning reduced HW flow and may cause the mixer to panic and start all thos pulsing......just a thought.
Thanks in advance, didn't appreciate that this post was going to be this long, any helps / tips / advice appreciated. As I said, I put this bathroom in myself so although I'm a scientist by trade I'm happy to tackle any solutions you can throw at me - cheers!
I have recently refurbished our en suite and am having a problem with the thermostatic bar mixer shower. When turned on, the pressure in the shower oscilates from good to poor and back again (at about 3 second intervals). I've found that if I remove the shower head tube from the mixer unit and let the shower run for 10 or 20 seconds this seems to fix the problem, but would rather not have to do this each morning. From elsewhere, it read that it could be air in the pipes causing this but unsure as to how to confirm / eliminate this.
Briefly, it's a gravity fed system. CW tank in loft, HW cylinder on same floor as shower. 15mm pipework running from respective tanks (i.e. up from HW cylinder) across loft joists and then drops down to the back of the shower which is a thermostatic mixer.
When I've run the water straight form the mixer unit and re-connect the hose the pressure is absolutely fine (not bad considering that the vertical measurement from the bottom of the CW tank to the shower head is approx 1m giving a mighty 0.1 bar pressure!) so I'd rather not go down the new system route (i.e. unvented) or install pump (little one on way and don't want the noise etc), plus another shower in the main bathroom works fine off the same system (but isn't a mixer shower).
One thing I've tried was to increase the HW tank temperature from 65oC to 70oC as I read that the thermostatic mixers like a hotter input - either way, this didn't work other than to ensure that I had a lovely hot shower (following the 'mixer drain' fix - clearly). Another thing I'm going to try tonight is to look at the mains / ballcock feed onto the CW tank in the loft, my logic being that if this has crusted up (limescale) then when the shower is on, cold water may be being used up at a more substantial rate than is being refilled, and therefore there is reducing levels in the CW tank producing less pressure in the HW tank meaning reduced HW flow and may cause the mixer to panic and start all thos pulsing......just a thought.
Thanks in advance, didn't appreciate that this post was going to be this long, any helps / tips / advice appreciated. As I said, I put this bathroom in myself so although I'm a scientist by trade I'm happy to tackle any solutions you can throw at me - cheers!