Glowworm ultracom 38 cxi F9 fault

[Heating Genie]

Had a call tonight regarding the fault code "F9". It relates to the system pressure and only seems to cause a problem with hot water that we know of. Sometimes it resets straight away and othertimes it takes a few attempts. Any ideas?

I can confirm the pressure is correct (according to the digital read out)and the vessel has been recharged. It seems to play up more when its been left for a few hours and not used.

 

[lame plumber]

had problems like this on a couple of cxis and it was the pressure sensor blocking, awful bit of kit coz you dont seem to be able to clean them out so have to replace as only option.