Condensate Pump

[Phillay]

Hi guys,

Looking for a bit of guidance regards my options.

Purchased a Grundfos Conlift 1 to install with our new condensing combi boiler. Our boiler installer didn't know how to wire this in so I spoke with an electrician friend. He couldn't understand the install instructions to0 well, so I contacted the manufactures.

The pump has a safety overflow cutout switch. My electrician advised this to be wired into the RF stat, however, after speaking with W Bosch, they advised that it needs to be wired in to cut the live supply to the boiler (as it condensates in DHW mode too).

We've seen all the wiring diagrams over the net which our electrician showed us... basically fuse flex to junction box, through the safety switch cable, back to junction box and onto boiler, so it cuts the live supply.

Checked this with Worcester Bosch regards warranty etc... They say this is not acceptable as the boiler supply must be in a run of continuous 0.75mm2 (the safety overflow switch cable from the pump is 0.5mm2).

All Worcester Bosch have offered up is using a relay that cuts the live supply. I have no idea if that's possible.

Does anybody have any ideas that they could offer up? I won't be attempting the work myself.

 

[sparkybob21]

what cables have you got from the pump itself? a 3core (brown, blue, earth) and a 2 core (2xblack)?

 

[davesparks]

I wouldn't wire it into the live supply to the boiler, if it cuts the boiler off whilst its firing it'll kill the pump overrun too.

Putting it into the switched live to the boiler would stop the boiler firing and allow the pump overrun to work as intended.

Alternatively with a Worcester boiler connect the safety switch so that it breaks the Ls supply from the boiler to the control system.

Neither method would break the requirement for 0.75 in the boiler supply, or require you to make the system more complicated than necessary.

Follow the KISS principal of engineering and you won't go wrong