Hi, I have the above boiler with potterton ep3002 timer and potterton room stst with hot water cylinder stat and 3 way motorized valve, honeywell, pumped. My problem is that the hot water is ultrahot and the radiators come on when the hot water is selected. so i gety both hot water and heating at the same time. I have check the motorized valve for operation and this seems to move to the correct positions. I was advised that the timer was at fault which was a potterton ep2002, upgraded to ep3002 now, but the problem still present. I have had to close all the rads dowm in order for the home not to be an oven!!!!! Any help really appreciated.

Paul, August 2007

Thanks. I was informed by a pro plumber! Will i need to drain my system down to change the valve. how do i rebalance the system?

Paul, August 2007

>My problem is that the hot water is ultrahot

turn the cylinder stat down to 60 but not above 65.

>the radiators come on when the hot water is selected.

the ball in the motorized valve is faulty and not shutting the heating side off fully.


>move to the correct positions.

don't tell you whats happening in the base of valve.


>I was advised that the timer was at fault which was a potterton ep2002, upgraded to ep3002

who by a diyer or a plumber ?


> I have had to close all the rads down

now the system will need rebalancing.


fit a new motorised valve and all will work fine.

hi-spec plumbing, August 2007