Hi, I have a Grohe red duo boiling water tap, only two months old and the boiling water function has stopped, the red touch light won’t even come on. Any ideas please. Cheers Rob

If you have single handle facute one bad cartridge in the system may be acting like a mixing valve and allowing cold water to mix with hot not allowing water to get hot enough .

If you spin the shower head off there should be a metal screen inside. If it is clear, Soak the shower head in CLR for about 4 hours. After 10 years even the best water supply will leave behind a build up that can plug the tiny holes.

valve should have a gear like deal under handle that may need to be adjusted

The thermostatic mixing spool cartridge may be worn out. The low water pressure may indicate sediment in the cartridge as well. This can be easily removed by hand tools

The thermostatic stop is set too low. Havent set a grohe before but most other thermostatic shower valves work similar. pull off the handle(however a grohe handle comes off . . ) there should be a notched ring or stop which keeps the handle from going all the way hot. pull out the ring and turn it a few teeth hotter put back and reinstall handle try water temp and adjust again if necessary.

from a plumber all hot and cold connections on all major showers are hot on the left and cold on the right just like the taps on your sink or washbowl

Hi,

If the hot and cold are fitted the wrong way round then the thermostat on the shower unit cannot operate properly!

Most thermostatic mixer showers have a 'bi-metallic' thermostat, if you supply the hot to the cold and vice versa IT WILL NOT WORK.

It is like wearing the left shoe on the right foot and the right on the left! It doesn't work.

Re-install the hot and cold to the correct supply, and this will sort it.

I hope this helps.

you need to change the cartridge, it is a temp control and is going bad so it keeps you from burning yourself it is like a mixing valve and is givng more cold water, that way you don;t get burned,,

if you have an access panel behind it, take it off then wedge a peice of wood between the pipes and the wall, if you do not have an access panel take the cover plate off and wedge the wood thru this hole, do not over tighten just snug it you will be fine, remember to chaulk around the cover plate when done let set up for 24 hours