Ideal Mini HE C28 boiler problem

[IforG]

I have a problem with my Ideal C28 combi. It's only just over 2 years old.
In the last few days, the boiler cuts out when providing DHW after running for about 1-2 minutes, then restarts after another minute or so. Not much fun having a shower!!
When starting the boiler after being off overnight, it runs for 4-5 minutes before cutting out, suggesting to me that it is a heat-related problem?
The same process when operating CH but that doesn't cause a real problem.
The 3 lights on the front of the boiler indicate an air pressure switch failure when the boiler cuts out. I have changed the air pressure switch but the problem remains.
Any ideas, please guys

 

[AfterburN003]

Sounds like a blocked Venturi to me.......cleaning is pretty straihtforward but should really be done by a RGI.

If you have your boiler instructions , procedure is in there......if you havent got instructions i can email u a copy of them.

 

[ChrisR]

PLate heat exchanger's blocked.

 

[IforG]

AfterburN003 - I should have said that I have already cleaned the venturi although it was as clean as a whistle, as indeed is the whole inside of the boiler.
On the top of the boiler, there is a capped vacuum test point. When the boiler cuts out, if I attach a tube to the test point and suck gently, I can hear the air pressure switch operate and the boiler relights.
So I guess there is a problem with the vacuum. Listening very carefully to the fan, there doesn't seem to be any variation in the fan speed but how much slower would it need to turn to lose the required vacuum level?

 

[Ihavenojob]

try the 2 thermisters,cheap as chips and a piece of p to fit

 

[IforG]

ihatemyjob - is that the two parts described in my manual as CH temperature probe and DHW temperature probe?

 

[Ihavenojob]

yes.both exactly the same

 

[Agile]

But it does sound as if its related to the flow switch otherwise the diagnostic lights would be indicating a faulty sensor. It could well be a flue fault which can need a gas analyser to help diagnose.

I cannot give you detailed advice on your problem as it needs a competent registered engineer and you have already done illegal work on your boiler.

So my advice is to get an engineer!

Tony

 

[IforG]

Hi Tony - your point is taken about getting a competent registered engineer, but that is where the problem starts.
My immediate response to having a boiler fault was to call in an engineer. He has so far spent nearly 5 hours on two separate occasions trying to resolve the fault without success. God knows what sort of bill he is planning to present me with.
It was he who cleaned the venturi and replaced the air pressure switch. He has checked the adjustment of the gas pressures. He seems uncertain of what to do next, and is now suggesting a replacement fan (at huge cost) but without any certainty that this will help the problem.
I have only got involved in this reluctantly in order to try and help the engineer solve the problem without bankrupting me.
Any other suggestions

 

[Agile]

You clearly have a totally incompetent person looking at your boiler.

You engaged him to repair your boiler and he has not done that.

You should not pay for hours of his incompetence. My view is that you should not pay him anything but as a gesture a small donation might be a good idea.

Call Biasi 0121 506 1340 and ask details of their local service agent in your area. ( Its made by Biasi ) They can take a while to answer and after 2 pm is probably going to be better.

If you really get stuck you can pay for me to take a day trip to fix it.

Tony