Vokera maxin 28e furnace cutting out

[Gavin Pike]

Hi there, i have a Vokera maxin 28e and it has started playing up over the last week or so.

For CH the furnace cuts out before hitting the room thermostat temperature. I have now turned the temperature control on the boiler to the maximum amount which delays the cut out, but the boiler seems to think it's (or is) overheating. When the timer kicks in for the first time in a cycle it runs for a little longer, but when it kicks in again after cutting out it only runs for a minute or two maximum.

When the a DHW tap is turned on the furnace will kick in after a few seconds. Sometimes hot water then comes out of the tap for 30 seconds or so, before running cold again, sometimes with furnace remaining on for another minute or so! I assume this means the boiler water is being diverted to CH rather than DHW where it's required.

Previous fixes to boiler by engineer were replacement of domestic diaphragm and (smaller) heat exchanger 05/2008. Prior to that replacement of faulty thermistor 11/2007.

My 2 year old son wants his bath back, he thinks electric showers are boring!

Thanks for any clues,

Gavin

 

[gas4you]

I assume this means the boiler water is being diverted to CH rather than DHW where it's required.

On the face of it this sounds like the boiler overheating, shutting down then firing up again. Usually a sign of a blocked plate HE, but as you say you have had this changes recently and the first part of the post indicates it may be doing this on ch, I would for now, discount this.

I would want to check the thermistor again and possibly the overheat stat and/or connections.

Apart from the repairs, has this been serviced and set up properly recently?

 

[Gavin Pike]

Thanks for the response Dave,

Checking my paperwork the last full service we had was 2 years ago. Having said that I would have expected the boiler to be fit for purpose for a good while after replacing something major like the heat exchanger (and spending £200+)?

If not, I guess I should arrange for a service to be included when the current fault is fixed.

One further bit of advice you might be kind enough to provide - the heat exchanger (part 8037) was costed at £113.97 + VAT on our bill, yet I've seen this as low as £53+vat on t'internet. I appreciate that there should be some extra cost for supplying and profit, but this seems a hefty loading. What are your thoughts?

Gavin

 

[gas4you]

One cannot say whether the cheap part on the internet is brand new or re-conditioned, regardless of what is printed. In fact the price you quote is cheaper than what I would buy it at

The part you have had replaced is the secondary plate HE and the price charged is probably what I would have charged, retail.

The current retail price is now £122.10 + VAT and on top of that would be the standard £60 + VAT attendance fee to fit.

It may be seen as profit, but when I supply a new part I have to warrant the job and the part for 12 months. If the part goes faulty I have to return to replace it and no one reimburses me for my time sadly.

Yes, it is a numbers game really and we all hope we are not called back, but unfortunately in business we have to cover ourselves for these circumstances and to offer a good after sales customer service.

 

[scatmanjohn]

Sounds like a classic vokera air flow problem.

Get a CORGI registered eng. to service it properly, ensure that the main heat exchanger/fan/ fan venturi are cleaned.


By the way, its a Combination boiler not a furnace

 

[Gavin Pike]

Thanks Dave, I see you're actually in Norwich like me - what are you under in the Yellow Pages?

I've left a message with my usual engineers and I'll ensure they give it a full service as well bu will keep you details in mind. The unit's probably been in the property for around 11 years what sort of lifespan would you expect this model to have?

Scatman, thanks for your note. I'll ensure it's serviced like you say. Maybe using the furnace to smelt pig iron as well as heating the home hasn't helped.

 

[gas4you]

I don't advertise in yellow pages. Too expensive and too many cowboys in there

Most of my customers tell me they would never look in there as they might as well just shut their eyes and stick a pin in

You can look me up from my profile if needs be.

 

[tonybhoy]

Sounds like the ignition board on the gas valve to me.