Cold showers!

[Mattenstein]

Hi all

I have a Mira Excel thermostatic mixer shower running from a Worcester 32cdi combi (I think).
Problem is at this time of year the mains water is so cold that the boiler can't keep up with the flow rate, so the shower on full flow is barely warm.
We have been running the shower with the flow lever half open in order to get hot water out of it but I wonder if this is detrimental to the health of the shower valve? Should I instead turn down the valve on the cold inlet to the boiler? This was done once before by a BG engineer and it worked but a subsequent engineer seems to have opened it up again. I worry that any valve not fully open may be subject to wear and tear but unless I restrict the flow to my shower it won't run hot in winter.

Thanks.

 

[JBR]

Hi all

I have a Mira Excel thermostatic mixer shower running from a Worcester 32cdi combi (I think).
Problem is at this time of year the mains water is so cold that the boiler can't keep up with the flow rate, so the shower on full flow is barely warm.
We have been running the shower with the flow lever half open in order to get hot water out of it but I wonder if this is detrimental to the health of the shower valve? Should I instead turn down the valve on the cold inlet to the boiler? This was done once before by a BG engineer and it worked but a subsequent engineer seems to have opened it up again. I worry that any valve not fully open may be subject to wear and tear but unless I restrict the flow to my shower it won't run hot in winter.

Thanks.

That's strange. We have a similar Mira thermostatic shower running from a new WB 35CDi condensing boiler. Is anyone else running hot water at the same time, or perhaps the heating is still on which, I believe, should go off when you run hot water?

Anyway, I'm sure someone who knows what they're talking about will be here soon!

 

[mcmoby69]

Duff shower valve.
Hot water supply pipe 22mm not 15mm to shower.
Gas supply undersized.
Water pressure very high.
Faulty thermostat.
Diverter sticking.

All possibilities. All should be checked

 

[Mattenstein]

Duff shower valve.
Hot water supply pipe 22mm not 15mm to shower.
Gas supply undersized.
Water pressure very high.
Faulty thermostat.
Diverter sticking.

All possibilities. All should be checked

Hmmm...Well the supply pipe is 15mm all the way. The gas supply is definitely 22mm as it was changed when the boiler was installed. The water pressure IS pretty high though. Like I said this only happens in winter when the incoming water supply is very cold, so unlikely to be the diverter valve, and it's not just the shower, I have to run a bath with the hot tap half open in winter too or it's barely hot, so unlikely to be the shower valve or thermostat. Indications are pointing towards the water pressure being too high and the boiler being unable to cope, which is what I originally thought.

 

[mcmoby69]

32kw boiler unable to cope?
Unlikely. Not impossible tho.

Might be 22mm all the way but could still be undersized. Has the incoming gas pressure been tested?

 

[Mattenstein]

I think it gets tested with every service and then when we had a new hob and gas fire installed too, I never got informed of a lack of pressure

I'm aware people will have differing opinions of BG engineers but the last time I brought this issue up with them they just turned down the valve supplying cold water to the boiler. I'll ask again though, is it bad for a valve to be left partially open?

 

[endecotp]

We have been running the shower with the flow lever half open in order to get hot water out of it but I wonder if this is detrimental to the health of the shower valve?

No, not detrimental.

 

[dilalio]

What’s the DHW temp set to on the boiler?

 

[polesapart]

The Mira Excel has an internal adjustment to limit the flow rate in this situation.

You need to turn the water off and disassemble the valve to access. Google the installation destructions first.

Meanwhile it does no harm to run the shower part open as you are doing.