Icos HE18 won't turn off

[RichHowells]

Hi,

Recently I had my boiler replaced with an Icos HE18, of which I had no input into the choice of boiler as its a rented student accommodation . It works fine, but it seems to have a mind of its own and heats itself whenever it feels like it, regardless of us turning the hot water or central heating on. No matter what we do, it'll decide if it wants to heat itself, and so we have to turn it off on the boiler, which is irritating to say the least. Any ideas of why this is happening and how i can stop it. We have an Icos HE18, a froststat and Horstmann H425 thermostat.

Rich

 

[sturharv]

Sounds like a control problem maybe. When you heating is off what temperature is it set back to? i.e. it may be set at 21 dec C when its on but the same when its off. Try looking at the Horstmann controller and see what the temp is when the heating is scheduled to switch off.

Hope that is clear enough!!

 

[nickso]

is the icos the combi? if so are you sure its not just the preheat switching on? displays t when it does it.

 

[corgiman]

no the combi is the ISAR nick

 

[nickso]

no the combi is the ISAR nick

damn ideal and there similar names

i though this was the case CM but thought id post anyway

 

[corgiman]

And why not Nick

I would hazard a guess at the Mid Position Valve or zone valves sticking

OR the lack of a pipestat

 

[gas4you]

Switch boiler off at wall for 30 secs then back on. I've had a few stick on ch that has just been the pcb glitched out.

 

[sturharv]

You could also try pushing the lever on the mid-position valve / zone vale manually to see if this swithes the heating off, it may be sticking.

Also, where is the boiler located (anywhere cold) it may be that the frost stat is keeping it on, if its say 5 deg C

 

[gas4you]

Icos does not have a built in frost stat

In fact very little built in it works anyway

 

[lor]

suspect it has had it pcb changed and they have inserted the jumpers as an isar. this will cause the boiler to fire to preheat itself.

 

[gas4you]

Switch off then on. What number comes up on the display?