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Grohe 1000 problem- pot luck whether water comes thru or not

Postby lynguss » Fri Feb 05, 2010 1:00 pm

Just had new bathroom installation with a Grohtherm 1000 & Tempesta Trio thermostatic mixer valve fitted. But we're having problems with the shower not working on a daily basis.

This problem is not consistent so its difficult to work out what's going on. I'm wondering whether it's the shower valve or something else. (Pump has just been replaced - problem still there)

Symptoms are:-

-no pumped water or only a trickle when flow valve is at normal position, but if you override the stop position and have it on full it's fine

-no pumped water on both of these settings

-sometimes there's nothing when shower head is in normal position, but if you drop it down to the bath it's fine - sometimes this doesn't work!

-once the shower stopped midway through a shower

-when it's not working, if you try again short while afterwards it's fine

-sometimes it works absolutely fine!!

-the temperature setting doesn't seem to matter

There seems to be no consistency. Most of the other taps and appliances in the house are supplied from the mains, so I don't think water supply is a cause.

Do you think this is likely to be a shower valve problem or something else? I would greatly appreciate any comments or advice anyone has to offer, as this is a little frustrating!

The setup is:- the Grohe 1000 valve over a bath being fed from a cold water tank on the floor of the loft (I have been told size of tank is fine), and hot water tank in airing cupboard next to bathroom. Both being pumped through a Stuart Turner Showermate 1.8 bar @ valve closed, 1.5 bar @ 9 litres/min, max flow 33 litres/min (an incredibly noisy pump too!! Any suggestions for that?)

Many, many thanks for any suggestions
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Simply Build It

Postby plumbbob » Sat Feb 06, 2010 4:57 pm

I think the first thing to check is to see if non return valves are fitted. Sometimes the pump has them too. Strictly speaking, they are not required in a low pressure system as there is no chance of backflow contaminating the mains water. In fact, having them can result in intermittent operation by preventing the water from flowing and triggering the pump when the shower is first turned on. Having to lower the shower head into the tray start the pump is a classic symptom.

It might be worthwhile cleaning any filters too. Debris not flushed out during installation or drawn in during operation can "float" around behind the filters and block them by almost a random amount.

I wouldn't wag a finger at the valve or pump. Well, not at this point, anyway!
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Postby lynguss » Sat Feb 06, 2010 9:25 pm

Thanks for your reply - will check the valves, or ask the plumber to, as he will be calling round.

I think there might be a wiring problem too, as the shower never seems to work first thing in the morning, which led me to play around with the central heating and hot water controls for the boiler.

Two or three times there was an instant reaction from the shower when I turned these controls on or off. Having had a few electrical problems in the house in the past (probably due to not very professional wiring when the house was built), we were not surprised.

Thought we had solved it, however it is still not right. We still don't get any pumped water flow when the shower valve is at normal setting - we have to depress the button to override eco-flow and then turn it back, or lower the shower head significantly to do so.

Will pursue your suggestion and let you know how we get on.

Thanks again.
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