Potterton Suprima 60 problems with hot water

[jim24]

Hi,
I wonder if anyone would be good enough to give me some advice.
Having moved into this property recently and having had the boiler serviced I find I have a problem with the hot water which I can't get hot enough even though I put the water on for two hours with it only gets just hand hot.
The system is in two halves, an underfloor system that seems to work fine as when I raise the temperature on the hall wall mounted thermostat the pump next to the manifold starts up and everything proceeds as normal.
The upstairs is normal radiators and a hot water tank. The tank has a small thermostat strapped to the side set at 60 degrees and there is a working Immersion Heater fitted with its own timer, this is switched off at the moment.
The Honeywell three port valve in the airing cupboard has a small lever with Auto at the top and Manual Open at the bottom, the lever is in the auto position but there is no resistance if I move it to the lower position.
This valve buzzes all night when the system is switched off however the other night I decided to leave the heating and hot water on all night, I turned the boiler thermostat to half way, it was on max and I noticed that the pump in the airing cupboard stayed on virtually all night, it would go off and start again within 2 seconds and then after about 10 minutes it would stop for a minute and then start again, after about 10 mins the cycle would start again.
After two hours running just on hot water this afternoon I felt the two pipes going into the hot water tank and found the lower one cool, the top one hot and the hot water coming out of the tap just hand hot.
I am not sure if the thermostat on the tank is just for the immersion heater. If it is what controls the circuit upstairs. I have thermostatic valves on all radiators and all but two are turned off, and one of those is turned low so there is not great demand for those when the heating is on but the pump in the airing cupboard is on virtually all the time.

 

[Simon F]

hello Jim and welcome along.
you say you have only recently moved, has the hot water been like this the whole time you have lived there or did it change after the boiler service you mentioned?

either way get the plumber back to take a look.
there are so many variables as to what the cause could be, the other side of a screen is not the best place to diagnose.
could be issue with :- the motorised valve, cylinder thermostat, is there a flow limiting valve fitted - is it closed?
the thermostat on the hot water cylinder will/should be to control the boiler not the immersion heater.

 

[jim24]

Thanks for trying to help.
No the problem has only occurred in the past couple of days, in fact since I put it on all night and I haven't changed any of the flow limiting valves.
If the thermostat on the tank is for the pump on the upstairs then it must be calling for heat as the water isn't hot enough. This would cause the pump to work but if the valve isn't sending the water through the tank its not going to stop calling for heat.
Can anyone tell me what lever on the Honeywell valve should feel like and the effect of changing it to 'manual open'