Ideal Isar HE 35 fault

[Dan-HybridHeat]

Customer complaining that rads are getting hot at random times, she said it displays a symbol on the front when it happens. I'm assuming it's either the preheat symbol or DHW demand symbol - she said it definitely isn't the C for heating.

I've changed the DHW thermistor as advised by Ideal but she says it's still happening. Even if one of these was coming on unnecessarily, why would it be sending the heat down the heating pipes so much so to make the rads red hot. Anyone come across this before?

Apart from this boiler operates fine with DHW and CH demands.

 

[gassafe]

Passing diverter, rads getting hot on water preheat maybe?

 

[Dan-HybridHeat]

Could be, somewhere to start at least

 

[GrahamM]

Almost defo divertor related as gassafe mentioned. Prob need change cartridge. Just check the head operating ok.

 

[Dan-HybridHeat]

Changed the cartridge today and is now working fine, cheers lads.

Funnily enough she said her hot water hadn't been so hot in a long time!