Changed faulty ACB now hot water not working!!!

I have just replaced the ACB control board following a pump failure taking out the previous board. I m now unable to get the hot water to work... going through the diagnostics it appears to me that I have bought a faulty replacement. Ive checked the jumper settings etc. When I go throught the diagnostics the board shows the DHW temp as around 80 - 85c yet the pipe is cold to the touch so I know that is wrong, if I fit the link between 36 + 37 it should force the 3rd bar on the display but although it comes on it almost immediatly goes off again and does not switch the DHW pump on.

If the sensor was faulty I would expect it to go into error rather than show the wrong temperature.

Any thoughts / advice?

Did you have to programme the ACB

I do think you have not booted the ACB correctly.
Mike
MGC/H2O
Norfolk

Hi Mike

Other than setting the jumpers and powering up Im not aware what else you can do to program or boot the ACB? The section of the Gledhill installation manual dealing with changing parts basically says you unplug the old one, plug the new one in, set the jumpers and power up.

I think it may be a sensor fault... I swapped the DHW & PHE over on the pcb and the temp dispayed for the DHW dropped and the pump kicked in. Im just surprised that a faulty sensor would show a temp rather than just going into error.

Do I have to drain the system to swap sensors or is there a way to isolate?