Intermittent hot water

[brotherdeal]

My hot water has stopped working the water is Luke warm at best with intermittent spells of warming up when tap is run for an extended period.

The boiler is running fine with the tank and pipes hot.

Would this system be described as an s plan system?

Would the blue pump on the left be a hot water circulation pump?

Any help on this would be greatly received.

 

[CBW]

I don’t think they‘re known as an S-plan as you don’t have motorised valves but 2 pumps. Check the cylinder thermostat is set high enough (the actual positioning looks low imo). Is this a new issue or has it always been the case?

 

[brotherdeal]

It's a new issue, we've owned the house 5 years system has been fine until this morning.

I've had different heating systems in other house but always found this layout to be confusing in its operation.

 

[CBW]

If the boiler is firing and the pipes are getting hot enough to heat the water, then it’s either poor circulation, limescale or possibly trapped air.

 

[stem]

Looks to me that it maybe a Thermal Store. If so, one pump is from the boiler that heats the cylinder, the second pump takes heat from the thermal store to the radiators, and hot water for the taps is provided from an internal coil that collects heat from the thermal store and mixes it with cold water to create water of a safe usable temperature. If so, provided the Thermal Store is reaching operating temperature, it maybe that the blending valve that regulates the water temperature to the taps has been inadvertently altered, or is faulty and adding too much cold.

 

[brotherdeal]

Thanks Stem it is thermal store and functions as the above diagram, the oventrop blending valve was sticking. I replaced it today and is now working perfectly, thanks for the help guys.