Hello,

I've had a good look around this site and can't find an identical issue, so I'm hoping someone can help.

I have a Ravenheat combi boiler, which is about 3 years old.
It's had two major problems already:
1. Wouldn't pump out hot water unless the central heating was on - solution was to change the thermistor.
2. Wouldn't work at all as the fan wasn't kicking in - solution was to change the PCB.

Now the new problem is I think possibly the reason why the PCB needed replacing. If you run hot water, then it works fine. We have a hot water shower and that never has a problem. However, the central heating starts the boiler, and then 10 seconds later, it turns off again. Then goes through that cycle time and time again. It stays on enough that the radiators do get hot, but I'm worried that over time it will blow the PCB and I'll need a new one again. This could well have been happening for ages, and be the reason why the last one went.

Any ideas on what to do? I keep phoning the bloke who changed the PCB (and installed the boiler in the first place) hoping he can help, but he's suspiciously ignoring all my calls for weeks now.

My worry about getting any old body in is that they seem to be pretty shoddy bits of kit, and it might take someone a few attempts, and lots of money, to get it right.

Any help anyone could give would be much appreciated.

Dave Smith, July 2008

wont light

darren, December 2009

I have a problem with my CSI85T the CH is working fine but the DHW is keeping off an on every few minutes!
Coa any one help me?
I will have to say that we have changed the fan this year and the boiler is only 30months old!

Vim., September 2009

I've just cured a similar cycling on/off rapidly problem on my new Ravenheat CSI A, non-combi, boiler by fitting a bridge to a jumper on the main PCB. When in heating mode, the burner lights then after a while shuts off, presumably under the control of the CH thermister. It waits at least 4 mins before lighting again, just as it says it should in the user instructions. However in the installation instructions it quotes a time of 2.5 mins. Poorly written, inconsistent instructions, I think.

Anyway the jumper with the missing bridge on my PCB is partially hidden behind the transformer towards the right hand end of the PCB. The jumper is a single pair of pins. Don't confuse this with the pair of jumpers not too far away at the back of the PCB not hidden by the Transformer.

Disclaimer: I'm not Corgi registered. I discovered this fix by trial and error after being given the hint about jumpers in this thread. It works for me but may not for you, due possibly to differing PCB designs. Try it at your own risk.


Whinge, read if you've nothing better to do: I'm dissapointed with Ravenheat. The Installation instructions were obviously not specifically written for my boiler since they referred to functions that could only be part of a combi boiler. The installation instructions differed on some important points with the user instructions. Some of the wiring colour codings in tha installation instructions were wrong. The factory fitted timer was wired to the power so appeared to be functioning but the switch terminals were not connected. There was a water leak from the pump connection when I pressurised the system. Finally I believe the missing jumper bridge was as a result of someone at the factory not fitting it after the boiler had been tested, it had been tested, right?

Unrepentant-tinkerer, November 2008

Hi Chris,

Thanks for that - it only has the main PCB, any idea which jumper needs removing? I've got the manual, but it doesn't mention anything that I can see about it.

I've finally got the thermistor, and will be trying that as well this weekend.

Thanks again,
Dave

Dave Smith, August 2008

If it's the CSI85AT and it only cycles on/off in heating mode it will be the small credit card size fan/ignition board if installed
If the boiler only has main PCB then it could well be that it's been left in test mode and will require a small jumper to be removed from PCB

chris, August 2008

Thanks both.
Heatdoctor - so they have 2 thermistors? That would make sense, as it must have been the hot water thermister that was changed last time. Is it easy to replace then? I'm a computer engineer, so I'm using to fiddling about with things - just never done this before.

ChrisGas - I've always thought the problem started when we had some storms a few months ago. We had tiles down off the roof, and a fence down in the back garden so it was pretty bad. And I always wondered if something had blown back into the boiler. Does that fit in with the hot water working fine though - in my simplistic world if there was a problem with the airflow then it would be for both wouldn't it? Genuine question...I'm guessing here.

Thanks again for your quick responses.

Dave Smith, July 2008

could be poor flow through the boiler causing it to overheat, could also be an airflow problem,

CHRISGAS, July 2008

its your ch thermister. guarenteed i always carry them in my toolbox for ravenheat, drop pressure through prv, and locate heating thermister usually on 22mm pipe hw thermister on 15mm. then sawp job done.

heatdoctor, July 2008