Nest replaced by Tado X and boiler pump now on continuously

MikeyC

Hi does anyone know how to stop my Bosch green star CDi boiler pump from being on all the time.
Thermostat and calling for heat works fine but pump is regardless of whether heat called for or not. Its annoying 😖
Anyone had this problem and solved it!

(Been thru wiring installation twice now to check if followed instructions)

Thanks

Montage

What type of boiler? System, combi or regular?

MikeyC

Hi - it’s a combi boiler

Montage

Ok. I don’t see how it could cause that.

There’s a chance you have a boiler fault that’s unrelated. Start by cutting power to the boiler and switching it on again. Might clear it.

MikeyC

I'm afraid switching on/off has not cleared it - pump whirrs away nicely all day and night - Taco support can't help - they checked my wiring and all seems ok.

strange that with my nest heatlink I had no problems so I might just reinstall it and save my Tado kit for if I ever get a new boiler/heat pump :-(

Montage

I’m not surprised they can’t help. It’s a pretty simple Combi with switched live as far as I know. There’s no obvious way to tell it to run the pump alone.

wateroakley

@MikeyC Have you checked the W-B FAQs:

https://www.worcester-bosch.co.uk/professional/support/troubleshooting/faqs/all-faqs/why-is-the-pump-running-constantly-on-a-greenstar-cdi-boiler