This question is regarding Grohe Grohmix Neotherm cartridge 3/4"" (34411) 47025000

Pressure & temperature failure.

Extreme temperature/very hot or very cold. very little pressure with cold flow ( a trickle), turn the tap slightly & water is boiling hot with a small increase in pressure. there is no control with the temperature settings. Would that be a fault diagnosis of the failure of this cartridge, & would replacement solve the problem?
Asked 5 years ago by Martin
Regarding the temperature fluctuation or cool running, it could be a faulty cartridge. However to check this if you have the shower fed from a combi boiler, see if you can get hold of the hot supply pipe before it enters the shower or perhaps as it leaves the boiler.


If when holding this pipe the temperature fluctuates or goes cool, then the problem is not with the shower but more likely with the boiler, as the shower can only deliver what the boiler sends to it.

Disregard the temperature at the taps as they have a different flow rate.

Answered 5 years ago by Barrie Seabright

Thank you for your reply Barrie.
It might have helped if i had mentioned that the water is fed from a conventional boiler with a hot water tank.
In view of this information have you any further suggestions to my problem or does this eliminate the boiler and confirm the fault is with the cartridge?

Thank you

Answered 5 years ago by Martin Bett

I would say you may have a faulty cartridge , giving the new information given.

Answered 5 years ago by Barrie Seabright

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