ravenheat CSI 120 Low Nox Combi boiler

[Coasterphil]

Can some one help with a little boiler problem I have.
Being the middle of summer the roomstat is set so as the heating will not come on and also the boiler switch is set to hot water only.
Every now and again it appears that the pump starts up and water circulates through the central heating (I can hear it in the radiator).
I sort of thought this might be in built design to make sure there is no build up of sludge anywhere if the heating is off for a long period (I thought it was logical ).
Today the heating actually came on, even though the roomstat is set very low and the heating/hot water is set to hot water only.
The display which normally indicates the temp was blank. The burner light was illuminated though.
I pushed the reset which didn't do anything. I had to turn the boiler off and on again and all was well again..

With thanks.....Phil..

 

[SortedPlumbing]

Does some radiators start to heat up with you run a bath?

If so it sounds like your divertor valve is passing,

 

[Coasterphil]

No, hot water is perfect (although I didn't try running the water when the heating came on by itself).
When the heating came on the hot water was not being used. I was just sat watching tv and I heard the heating come on. Very strange.
I fogot to say that when the heating came on by itself as well as the temp being blank the heating indicator light wasn't lit either.

I was sort of thinking that it might be the PCB but didn't know if again it was some sort of action to keep the heating system in good condition during long periods of non use.

It's been a few hours and it hasn't happened again but like all these faults it probably will.

 

[picasso]

is there a frost stat fitted?

 

[Coasterphil]

It doesn't list one in the list of spare parts or on the wiring diagram in the manual.
I've had a feel under the boiler just in case of a leak and water getting into the electrics but all is dry.

 

[picasso]

I dont have the manual for this boiler so cant tell if it has an frost stat built in or not, but I think your first instinct about the pcb was correct.

 

[Coasterphil]

Thanks all for your advice.
I just wanted to see if anyone knew if there might be a reason this would come on if it was working correctly.
I'll see if/when it happens again.
It is still under warrenty (second year) but I did fit it myself so might have aggro trying to get them to look at it. I did have it checked out after I fitted it by a Gas Safe man who filled in the paperwork on the back of the manual.
I didn't want to fit it but couldn't find anyone who would fit a boiler I had supplied.

Thanks again...

 

[transam]

120 ravenheat has frost protection it is something like 7or 8 degs pump runs below that boiler fires , I think ?? untill the 7 or 8 degs is reached !
??????

 

[onlyfitidealboilers]

why did you want to supply it, 9 times out of 10 the gas engineer will get you the boiler for what he gets if for, "trade price".

 

[gas4you]

why did you want to supply it, 9 times out of 10 the gas engineer will get you the boiler for what he gets if for, "trade price".

Sorry to disagree, but everyone I know always adds a mark up on boilers they supply. Mostly to cover for the warranty period.

I would nearly always fit a customer supplied boiler, but would offer no warranty on it and charge a standard call out if the customer ever had problems.

 

[onlyfitidealboilers]

oh nice one gas4you, tell the whole world we add x amount on top well done.

 

[Agile]

Sorry to disagree, but everyone I know always adds a mark up on boilers they supply. Mostly to cover for the warranty period.

I would nearly always fit a customer supplied boiler, but would offer no warranty on it and charge a standard call out if the customer ever had problems.

Have you forgotten that you know me?

I dont add any markup, although a £10 delivery/collection charge sometimes.

Our installation charge of about £840 covers any warrantee attention.

Tony

 

[Coasterphil]

No frost protection listed in the wiring diagram unless it uses one of the other temp sensors. It does state in the manual if it is likely to freeze the system should be drained.
As for markup, I work in the motor trade and knowbody marks up like the motor trade but I would be very surprised to find a trade that didn't do it. I would almost expect it.
Boiler has been ok to now but I'm sure like car faults it will happen again.
My only slight wory is that if the circuit board is switching the heating on without being asked, will the circuit board take any notice of the sensors/safety cut outs? It did get hotter than it was set at (radiators too hot to touch).
I tried about 3 gas engineers to fit it and know luck, they didn't even want to connect the gas and check the settings after I fitted it (all but gas). I would have thought easy money?

 

[Agile]

All modern boilers use the NTC sensors to identify a frost risk.

With the boiler totally cold remove the sensor plugs and measure their resistance!

Tony

 

[Coasterphil]

NTC sensors, same as on cars .
I'll check them whilst they are working and make a note of the readings and if it gives me aggro again I'll check them again.
There appears to be 2 sensors. Hot water sensor and Central heating sensor. According to the parts list they are both exactly the same, so if the boiler is cold (obviously hot water not been used or central heating) both sensors should have the same resistance (give or take a few ohms).

Thanks again all for your advice... Will let you know if I find anything.