Mend Grant Combi Max V3 Home Heating Systems

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Mend Grant Combi Max V3 Boiler Oil Pressure Switch

Grant Combi Max V3 oil boiler - low pressure switch?

Hi,

Having recently replaced a leaky PRV in the above boiler I noticed that the low pressure indicator light failed to illuminate when the system was empty.
I'm looking to replace the pressure sense switch (which I'm assuming has failed stuck closed as it shunts the indicator neon which is in series with the boiler mains supply) I notice the switch assembly seems to plug into a metal bush screwed into one of the boiler HW pipes. The switch is held inn place with what looks like a small metal clip.
However, if I remove the switch using the clip will this cause the system to instantly depressurize or is there some diaphragm in between the switch actuator and the "wet side".

Thanks in advance,

Pete

Pete7457
October 2009

Grant Grant Combi Max V3 Heating, Home Heating Systems Boiler Oil Boiler Pressure Switch

I have a pipe in the way when I am trying to screw the new switch on will I mess anything up if I undo the nuts and move the pipe so I can screw it back on?

James
June 2015

Partscenter (part of Wolseley)

www.elanar.co.uk
October 2009

Thanks very much - it is as I suspected!

BTW - can you recommend a supplier of Grant spares? I live near Glastonbury in Somerset.

Thanks again,

Pete

Pete7457
October 2009

Release the pressure Via the PRV first otherwise you could get burnt by scalding hot water., you have the old style switch fitted , pull out the metal pin and then pull out the old switch, the new switch will be diffrent, you will have to remove the brass fitting (that he pin fits into) from the manifold, make sure you use TWO spaneers to do this (one as a hold against). the new switch screws directly into the manifold (use PTFE tape on thread) wiring is straight forward.

www elanar.co.uk (Grant Service Agent South East)
October 2009