Vokera 20-80 RS Flowmatic

[anne08]

Hi guys, here's hoping you can help me out with this one...
I have a combi boiler as above. Not been serviced in years (previous owner!).
I've been having to fill the system with water every few weeks because of falling pressures. Then my boiler started making funny noises. The noise is a creaking sound, like something needs to be oiled. It only occurs when the central heating is on (whether or not the boiler is fully fired) and when a hot water tap is turned on it stops for the period that the tap is on.

I got my boiler serviced. The major issue noticed was that the diaphragm had gone and the heat exchanger cracked. The diaphragm was changed and I've been quoted to get the heat exchanger and all appropriate other items replaced (£350). The plumber wondered if the noise might have been caused by trapped air in the system

Initially after the service the noise went. However the noise has started again, though it's not as bad as it was before the service.

I have 2 questions for the forum:
1) What do you think is causing the noise?
2) Given the age of the boiler (over 12 years old or so) is it worth repairing the heat exchanger or should I get a whole new boiler (£3000 including changing the piping from the gas meter)?

All comments gratefully received!

 

[scatmanjohn]

Hi...

Its hard to tell without hearing the noise, could be a few things.

£350 for a new heat exchanger is a tad steep.

I'm sure you can get it done for half that.

 

[DP]

I would be looking for second oipinion on the heat exchanger.

How long did the service take? What was done to the boiler, do you know?

Are the radiators valve open or are they turned off?

 

[anne08]

The service guy seemed quite good. The entire service took about 1 hour, and the boiler was pulled apart a bit. He demonstrated a rather well cracked heat exchanger to me.
It is not just the heat exchanger that needs to be changed, there are a few more parts that also need to be replaced linked to it. Sorry I can't come up with the names of these parts!
Unfortunately I am not sufficiently knowledgeable to know about the radiator valves, but the radiators that the boiler supplied are on.

What do you think is reasonable price wise to pay for the heat exchanger alongside labour?

 

[scatmanjohn]

Which heat exchanger are we talking about?

Did it have lots of fins on it or was it a white barrel shaped thingy?

What did he say was wrong with the other parts that need replacing?

 

[anne08]

The heat exchanger was a box like thing with a fan on the left upper side of it, and the pilot light is in the front of it. When the boiler fires the whole box gets a flame in it. Measures about 25cm across.
Hope that helps you work out what it is! Sorry I have such poor knowledge.
I think the pads inside it need to be replaced, and possibly also the thermostat...maybe. Unfortunately I haven't yet got the written quote to have full details. The quote of 350 includes VAT and all labour.
Still wonder if I should cut my losses and shell out for a new boiler...

 

[DP]

The insulation panels will discolour if heat exchanger water leaks onto them. Discolour they will also if rain comes down the flue leading one to think the heat exchanger is leaking.

I regularly repair these boilers. I like the build quality. An installer will say replace it, I say repair it.

 

[Agile]

If the metal heat exchanger was cracked then water would come out.

Its probably a cracked insulation panel and these would be about £20.

£3000 for a new boiler is an indication that he is very expensive. You could get a similar power boiler fitted for £1500 all in!

Tony

 

[ChrisR]

Curious to know which part was cracked:

 

[anne08]

Thanks for the diagram.
I think it's the combustion chamber that's cracked, but I guess it's conceivable that it's just an insulation panel. It was explained to me that the diaphragm had gone, thus the fan had stopped working, so that the temperature had built up in the combustion chamber and cracking the casing. Is that a common problem?

Re getting a new boiler: I've dug out the quote. It's 2800 which includes VAT, Worcester Bosch 25Si combi boiler, upgrading the piping from the gas meter (currently too narrow, distance about 6-7metres), mechanical power flush, replacing existing 6 thermostatic radiator valves with Danfos ones, a programmable room stat and removal of old goods. Is that reasonable? Do I need the Danfos radiator valves?

Thanks to everyone who has commented so far: much appreciated!

 

[DP]

Place of residence please. If Glasgow or hereabouts, might be able to to offer second opinion.

 

[ChrisR]

Building regs require thermostatic rad valves in at least the bedrooms.
Steep quote. Depends on that gas pipe run and where you are. etc etc!

 

[anne08]

I'm in Edinburgh. Is that near enough for a second opinion? 2nd floor flat.
The radiators already have thermostatic radiator valves, so why the need to change to Danfoss ones?

 

[anne08]

I've just got the written quote through. The bits that need to be changed are:
Heat exchanger (1 side)
Rear Heat Pad

The quote (£350 inc VAT and labour) also includes fitting a gas valve suppressor as there is interference with my TV and radio from the boiler.

Is this a lot more than I should pay?

 

[ChrisR]

Selected Product:478056

Description VOKR 6027 COMBUSTION CHAMBER
Manufacturer's product number : 6027
Retail Price (Excluding VAT and quantity discounts) £21.93

And a sheet of insulation, if not included in the above, is about 6 quid.

And

Description VOKR T0030 SUPPRESSOR
Manufacturer's product number : T0030
Price (Excluding VAT and quantity discounts) £6.26

Is this a lot more than I should pay?

That would ba a YES, then.
Do yerself a favour and call DP.