Thermostat on hot water cylinder

AP77 · 31 Jul 2019

Good evening,

I am trying to help an elderly neighbour.

The hot water from their taps seems way too hot. I have checked the temperature setting on their hot water cylinder thernmostat and it is set to 50 degrees which is almost the coolest setting. If I turn the thermostat clockwise I hear it click around d 70 degrees. Does this mean that the water temperature in the tank is around 70 degrees?

If that is the case, then can I assume that the thermostat needs replacing as it is allowing the water to get to 70 degrees and not cut off at the set temperature of 50 degrees?

Many thanks.

mrStat · 31 Jul 2019

Not necessarily- could be a stuck open zone valve. What kind of system is it?

AP77 · 31 Jul 2019

Thanks for the quick reply.

It's a Worcester Bosch condensing boiler. In a bungalow. Hot water cylinder is in the airing cupboard at ground floor level. Cold water tank is n the loft.

mrStat · 31 Jul 2019

Sorry, I meant what kind of system, S-Plan, Y-Plan, vented/invented hot water?

Is the immersion turned off?

Is the boiler actually running and trying to heat the hot water?

AP77 · 31 Jul 2019

Thanks, it's an open vented system, I believe.

Immersion is turned off.

The boiler does run ok and heats the water (and radiators when required). It's just that the water in the taps, etc, seems to be far too hot, despite the low setting on the hot water cylinder thernmostat. If the boiler is switched off and left for 5 or 6 hours the hot water from the taps does seem to be a little cooler.

AP77 · 31 Jul 2019

Thanks, it's an open vented system, I believe.

Immersion is turned off.

The boiler does run ok and heats the water (and radiators when required). It's just that the water in the taps, etc, seems to be far too hot, despite the low setting on the hot water cylinder thernmostat. If the boiler is switched off and left for 5 or 6 hours the hot water from the taps does seem to be a little cooler.

dilalio · 1 Aug 2019

Either upload some photos of the pipework around the cylinder or look for one or more boxes (metal or plastic, about the size of a block of butter) on the pipes. Then report back... 1 box is a Y plan, 2 boxes S plan.

undertrained · 1 Aug 2019

Is the thermostat making a good contact with metal on the cylinder?

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Thermostat on hot water cylinder

undertrained

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