Grant Vortex 26 combi boiler help!

[Nathzy01]

Hi all, new to this forum and hoping to find some advice on my Grant Vortex 26 external combi boiler,

Basically the heat exchanger sprang a leak, dripping on to the terminal box of the hot water pump below causing a short. I replaced the pump and the fibre washers on the heat exchanger, problem sorted....

Since then the hot water pump runs constantly when the hot water is selected on the controller inside the house, from my understanding the pump should only run when the hot tap is turned on and hot water is being called for? If I deselect the hot water from the control panel the pump turns off. Ive heard the pump control PCB is a common issue on these boilers that can cause the pump to continually run? I'm a fairly compotent DIYer and have can use a multi meter, I was just hoping someone could point me in the right direction or has had any experience with this before?

The pump itself is getting extremly hot, im guessing from continually pumping hot water...

TIA....

 

[John.g]

Some of these boilers were conventional I think with a diverter valve and one circ pump, others had no diverter valve but a extra domestic hot water pump which circulated water through a primary store which was kept continuously hot if hot water was selected, don't know if you have this type or not but it might be something as simple as a flow switch that is keeping it running.

 

[exedon2]

Hi is the flow light always on?
If so probably flow switch jamed open easily cleared odd times needs new flow switch
Check that the hot water tank statis closing when up to temperature.
Otherwise probably the board ive see the Grant boards taken out by a short-circuit before.
Try talking to Grant technical they will talk you through all require tests.