No Hot water

[Thor]

I have a thermal store system about ten years old. About two weeks ago the hot water went luke warm & the flow was poor. The central heating system is ok. The hot water is derived from mains pressure which is reduced by a diaphragm reducer, then double check valve, then through a coil in the cylinder which is heated by the cylinder hot water. This then is mixed in a blending valve to the taps and shower. The pump and boiler supply is working ok.

I suspected the blending valve as the hot pipe out before the blender was considerably hotter than the pipe to the outlets.I have changed this but no difference. The hot water taps are mostly now cold although you get a short burst of luke warm water occasionaly. Also the water seems to be pulsing.

There is a thermostat on the cylinder for the water temperature which is set between 60 & 70C

Can anyone can help me please?

 

[ChrisR]

I have no experiennce of these systems at all , but if the blending valve has HW on the input (correct side?????) then you should be able to adjust it to get hot out. So what happens if you try?

If you have the HW on the wrong side I expect you would be able to get either very hot or very cold water, only. Because that's what shower valves do!

 

[Thor]

I have no experiennce of these systems at all , but if the blending valve has HW on the input (correct side?????) then you should be able to adjust it to get hot out. So what happens if you try?

If you have the HW on the wrong side I expect you would be able to get either very hot or very cold water, only. Because that's what shower valves do!

Thanks chrisR

Yes it is a basic mixer but there is no hot water coming out even when its set on max. The short hot pipe from the cylinder to the blender gets so hot it can't be touched but the outlet pipe is luke warm. As i fitted a new blender because of this it can't be the problem

By the way if I have replied wrongly, I apologise as iam new to this forum

 

[kevplumb]

what chris is saying is
are you sure the mixer is fitted the right way round

 

[Thor]

what chris is saying is
are you sure the mixer is fitted the right way round

Yes it definitely is.

 

[kevplumb]

shot in the dark is the cold flow in ok

 

[Thor]

shot in the dark is the cold flow in ok

The mains pressure into the house is ok and the water into the cylinder is ok.

I just wonder if there is an air block somewhere or could it be something to do with the pressure reducing valve. Apparently the hot water system must not be above 2 bar.

 

[kevplumb]

there could be a blocked valve filter is the flowrate ok

 

[Thor]

there could be a blocked valve filter is the flowrate ok

The flow rate is poor but the only filters are on the blender which is new anyway. It might be the coil in the cylinder might be blocked?