radiators ok,but only hot water when ch is set to off

[brucieboy]

Hi

I'm not a plumber,I work in the water industry,only do menial jobs washers ball valves etc in my house but got a basic idea about ch systems,so just want some advice

I have a tank fed gravity hot water system with a separate F & E tank for the primary system

My time controller has 2 sliders,1 for Ch ,1 for hot water

When both are ON,all my radiators work fine,but the hot water struggles to get to a reasonable temp

When I set the Ch to OFF,and water to ON,the water heats up fine within an hour

There is a 3 way valve-when I set the ch to OFF it appears to close ok

The main house thermostat clicks when i turn it and the boiler turns on and off etc,according to the temp,so appears ok

The heat stat on the cyclinder is set to about 70c.


So appears the boiler is heating,but can only get correct temp of water when CH is off..at least that is what I can deduce

Of course somone will know better,hence I am asking the question !!

Thanks Bruce

 

[Whn1]

Has it always been like this? Possible poor pipe lay out, if not dodgy 3port.

 

[brucieboy]

no only last 2-3months,was ok 2 years before

 

[bewsh]

If it's got a mid-position valve, it wouldn't be gravity hot water mind.

If you put c/h and h/w on at the same time, have a look at the valve, has it got a little paddle that indicates what position the valve is in? If so, is it in the mid-position?

 

[brucieboy]

No goes as far as it can to the right,with Ch and HW on,and to the left when i turn CH OFF

It doesnt appear to stay in the middle

The valve is : bgmvsp 23 with a blue casing