Chaffoteaux Celtic FF. Pressure switch hunting.

[03sinclair]

What causes a flue pressure switch to hunt continually?

 

[scatmanjohn]

Hunt for what?

Please explain.

 

[03sinclair]

a switch that is said to be 'hunting' means that the physical switch contacts do not make a proper contact. Instead they pulse of fluctuate continually.

 

[pannierstan]

What causes a flue pressure switch to hunt continually?

On the Chaff Celtic usually fan not running fast enough is a classic that is never found. Possibly venturi partially blocked.
Its very rarly the switch itself but everybody always replaces it

 

[03sinclair]

new fan fitted, so will look at venturi thanks

 

[03sinclair]

Not the fan speed, not the venturi blocked or partially blocked. It turned out to be a small crack at the base of one of the plastic nipples on the underside of the presure switch (the nipple that plugs into the shorter pressure sampling tube in the flue). Only found it by accident! Bit of epoxy and all is well now.
Thanks to all.

 

[Baxmax]

Mmmmmmm Epoxy on nipples.....

Doh.......