boiler controller/wiring issue

[awaters]

Hi

I've a baxi solo boiler fed by a water tank in the loft, pumped system. I had a problem last year where first thing in the morning the CH would only come on if the HW was due to come on as well. No great issue as you normally set it up so they both come on before you get up.

Later in the day I never noticed an issue. Ie CH heating seemed to work alright must of the time. Ie the problem was intermittent and worst when the boiler was cold and had been off for hours. I ran a multimeter over everything and it seemed ok.

This year I've given in, purchased a danfoss heating kit and replace the programmer (715si) and mid point actuator and now its more confusing. If the CH is set to on or auto then the HW cannot be switched to off. When you scroll through it completely skips off. If the CH is off then you can turn the HW off. The cylinder thermostat works fine.

I've gone through the wiring and everything matches the wiring diagrams. I don't understand what could cause the controller to not allow you to turn HW off.

Any ideas would be appreciated.

 

[hertsboilers]

A programmer normally has a dip swith for gravity or fully pumped system. Yours might be wrong postion of gravity system.

 

[awaters]

I knew it had to be something simple like that! There are 4 dip switches, the first one is not used but I'd moved that one by mistake. I've looked at the back off that 20 times without noticing.

What a numpty.

Hopefully that fixes the power up problem finally.

Thanks