hot rad when it shouldnt be

[smiffy01uk]

Hi
I am having a problem with my central heating and water heating.
If I have the heating turned off the rad in my bathroom gets hot when the heating is not on, but if i turn the boiler system off and heat the water with the electric i get my whole cold water system fill up with hot water(this includes the toilet, not too good )
I have no idea why this is happening and am hoping someone on this forum can shed some light on this problem
Many Thanks
Smiffy01uk

 

[COG]

It has to be a bad bit of plumbing if your getting a hot flush.?

 

[MANDATE]

Regarding the bathroom radiator, many builders fitted the bathroom radiator to the hot water side of the system as normal practice so you could have warm bathroom while heating is off, so it depends on your system pipe work whether or not this is a problem.
The second part of your problem suggests the heated hot water is finding it's way to the water cistern(tank) and you will most likely find the toilets are fed from the cistern, although in some cases they are fed direct from the mains supply.
Has the pipe work been altered in some way?
I would start from cold with boiler off,switch on the electric heating and feel the pipes as the cylinder heats up.
There are only two ways the heat can get back to the tank, either the cold water feed pipe from tank to cylinder, or up the expansion and overflow pipe.
A faulty ballcock valve may be to blame.It may be the level of water in the tank is now above the outlet of the overflow pipe and has created a circuit in which the hot water rises into the tank and then circulates like a gravity system operates.
If this a new/recent problem and it has a history of good operation then I would not suspect incorrect pipe work.