HI, I have a Worcester Bosch combi boiler (Greenstar 30CDi) which seems to work very well, supplies loads of HW to the WHB and kitchen. Problem is we have a Grohtherm 2000 thermostatic shower and bath filler and the lack of pressure means its almost impossible to take a shower under it and it takes 20 minutes to run a bath. I am wondering is it simply a case of we need a pump on the shower? I understand that this is a problem with a combi? Is it likely that there's a fault with the shower valve? When the valve was flushed loads of water came out! Any help would be much appreciated.
Pressure problem with a Grohe Thermostatic shower
- Thread starter architete
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You're right, you can't fit a pump directly in line with a combi boiler.
Check that the shower's inlet filters and/or flow restrictors are clear of debris.
What is the pipe run like from boiler to shower?
could this be a flow rate issue rather than a pressure issue ?
what size are the feed pipes for the shower ?
how is it running just cold water?
are there any non-return valves fitted ?
the Grohetherm 2000 is a 1/2" inlet/outlet shower, designed for high pressure, correct ?
Have you called Grohe and asked them about it? their customer service is quite good - while your on the phone, ask them if a Grohetherm 3000 3/4" would be more suitable
what size are the feed pipes for the shower ?
how is it running just cold water?
are there any non-return valves fitted ?
the Grohetherm 2000 is a 1/2" inlet/outlet shower, designed for high pressure, correct ?
Have you called Grohe and asked them about it? their customer service is quite good - while your on the phone, ask them if a Grohetherm 3000 3/4" would be more suitable
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could this be a flow rate issue rather than a pressure issue ?
what size are the feed pipes for the shower ? 22mm I think, whatever size fits the fitting, the pipes are the right size
how is it running just cold water? VERY POOR
are there any non-return valves fitted ? Don't think so
the Grohetherm 2000 is a 1/2" inlet/outlet shower, designed for high pressure, correct ? Yes
Have you called Grohe and asked them about it? their customer service is quite good - while your on the phone, ask them if a Grohetherm 3000 3/4" would be more suitable I called them and they were pretty bad, they said they'd call back but I got nothing.
I am going to get my plumber in to have a look!
what size are the feed pipes for the shower ? 22mm I think, whatever size fits the fitting, the pipes are the right size
how is it running just cold water? VERY POOR
are there any non-return valves fitted ? Don't think so
the Grohetherm 2000 is a 1/2" inlet/outlet shower, designed for high pressure, correct ? Yes
Have you called Grohe and asked them about it? their customer service is quite good - while your on the phone, ask them if a Grohetherm 3000 3/4" would be more suitable I called them and they were pretty bad, they said they'd call back but I got nothing.
I am going to get my plumber in to have a look!
i hate that, when people say they will call back and then dont bother - sorry to hear that they did that, as i have to call them about something soon too.Asking your plumber is always a good idea, as he will have amassed a fair bit of experience over the years and could save you some costly mistakes.
Do you still have a tank in the loft?
Sometimes silly plumbers leave it supplying the cold water, which WOULD make it very slow. The thermostatic mixer would then have to cut the hot right back as well.
If that's the case you'd get more flow if you turned the temp to max.
There can be filters and non return valves in shower mixers, which can restrict flow a lot even if they don't block up, and stop it if they do.
To quanify things, measure the hot and cold flow separately from the bath tap, on min and max temps. Use a 9 litre bucket and time it, or similar.
Sometimes silly plumbers leave it supplying the cold water, which WOULD make it very slow. The thermostatic mixer would then have to cut the hot right back as well.
If that's the case you'd get more flow if you turned the temp to max.
There can be filters and non return valves in shower mixers, which can restrict flow a lot even if they don't block up, and stop it if they do.
To quanify things, measure the hot and cold flow separately from the bath tap, on min and max temps. Use a 9 litre bucket and time it, or similar.
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