burner in combi boiler goes on off when hot water used

[russellpeters]

Hello Forum Members,

For about the last 4 weeks we have had an issue with our combi boiler's ability to heat domestic water.

Whenever hot water is used the temperature of the hot water is inconsistent and keeps going up and down every 20-30 seconds - from tepid to very hot back to tepid and so on.

This happens at all locations where hot water is used - kitchen sink, bathroom shower etc. The pressure is normal and steady like it always has been i.e. it does not increase or decrease abnormally.

Earlier today I realised that this intermittent supply of hot water is because the boiler burner switches off and on every 20-30 seconds. The sound coming from the boiler seems to rise to a high level when the burner comes on (similar to a plane taking off just much milder) and then when the burner switches off the sound drops suddenly.

The boiler is an Ideal Independent C30. The boiler is less than a year old.

The boiler has a number of "fault codes" but the display does not display any fault code. I have consulted the troubleshooting guide but it does not have any guidance for this intermittent hot water / no hot water issue.

We have also had a water softener from Harvey Water Softeners for the past 3 months.

Can you help me out please? Thank you.

(edited: to add a couple of more details about the boiler.)

 

[Dan Robinson]

That kind of boiler is usually fitted by those that throw a boiler at the wall and hope for the best.

I would say that the plate heat exchanger is blocked due to a lack of flushing.


Mind you, being a cheap Ideal boiler, it's doing well making it to a a year

 

[ianmcd]

well as it is only a year old then it will be still under the manufacturers warranty as these came witha 2 year warranty, if it was registered, but I suspect that it was never registered as it sounds like a cowboy install to me or you carried out the install yourself, cheapest is not always best

 

[Agile]

Many manufacturers will not cover dirt in the plate heat exchanger.

They say its not the manufacturer's dirt!

Tony

 

[ianmcd]

Many manufacturers will not cover dirt in the plate heat exchanger.

They say its not the manufacturer's dirt!

Tony

I like that one Tony

Reminds me of when a Gas Supplier says that "Black dust" sometimes called Shale dust did not come through the mains, so where did it come from then ????

 

[russellpeters]

Thanks for all your replies.

Is there any easy way to attempt a fix/repair? Either by changing the relevant part or cleaning using flushing chemicals?

Also what would you recommend we do (chemical inhibitors/descalers, magnetic debris collector) to minimise the chances of this happening in the future?

We bought the house 10 months ago from a "professional" developer and he has "fixed" a number of things very superficially so I would not be surprised if this boiler is at the very low end of the market. Plus I am positive that the central heating plumbing was never flushed (not sure if this has an effect on the domestic water heating) so maybe the boiler has decided to finally give up.

 

[russellpeters]

Forgot to mention that we do have a Gas Safe Register Building Regulations Compliance certificate for this boiler from January 2013. Does this help?

 

[Dan Robinson]

It might help you get the installer back under warranty.

A blocked PHE is blocked due to the primary water (that also runs around the rads) clogging the water ways on that side of the exchanger.


Sounds like a typical "fook it we're selling" job to me. You are the unlucky recipient.