No hot water, radiators boiling hot

[andyboiler]

I have a Vokera Linea 24 combi boiler (ten years old), and it has been nothing but trouble for the last eight years. We have had numerous engineers (at least seven), who have never really solved the problems, which are currently:
No hot water, despite only water selected, but the rads are boiling hot, despite the heating being switched off.
The pressure on the boiler keeps going up to 3.5 bar, and then tripping the safety valve.
This weekend, for the first time, a code 2 error (overheating) came up on the display, so I turned it off for half an hour to recover.
Does anyone think this boiler is basically knackered, and would it be easier to install a new boiler rather than try to fix it?

 

[Agile]

These are perfectly repairable but obviously it needs someone who knows what they are doing.

I expect that the diverter valve motor is failed in the CH position. Perhaps as a result of a leaking shaft gland.

The pressure rising so high implies the expansion vessel is failed or needs recharging. You can read about it in the FAQ on this site.

What are you going to do now?

Tony

 

[gas4you]

Overheating could be a sign of a blocked/partially blocked HE or plate HE depending when it overheated.

 

[andyboiler]

Thanks Tony and Dave, I half suspected the diverter valve motor, but it is way beyond my capabilities to start trying to fix the thing. We do live in a hard water area, so the system gets bunged up. The last guy cleaned the heat exchangers about six months ago, but the system has never had a powerflush.
I am wondering if it is worth repairing as it is ten years old, or should I go for a more reliable replacement, such as a Worcester Bosch or Vaillant?
I'm as confused as that guy in the old Fast Show sketch in the pub

 

[Agile]

I would say its well worth repairing but I repair boilers! There is no evidence to me yet that the heat exchanger is blocked but merely cleaning it and not dealing with a dirty system is only a temporary repair.

So far I only think the diverter motor is failed and not that the plate HE is blocked but it could be as well.

The diverter motor has probably failed as a result of dirt causing the gland to leak into the motor.

If you can take the motor off and jam the pin inside down then you will help to diagnose the extent of the problem and might get some hot water!

Tony

 

[andyboiler]

We have got one of those in line scale inhibitor thingys, but I guess that they are about as much use as a rubber chisel.
What do you reckon on the rough cost of powerflushing the system, sorting out the diverter valve and possibly fixing the expansion vessel (if it is damaged)?
I know this is like saying "how long is a bit of string", but the truth is that we are really strapped for cash (isn't everyone nowadays), and after the last lot of "engineers" I am a very sceptical person.

 

[andyboiler]

I have had a few quotes for work to be done on the existing Vokera, and the list looks like this: New diverter valve/motor, powerflush the system, possible new expansion vessel, possible problem with PCB - possible total, around seven hundred quid. Is it worth it with a ten year old boiler?
Option 2 - new Worcester Bosch, system powerflushed all in cost around eighteen hundred quid - ouch!!!!
What do I do????

 

[gas4you]

Basically whoever has quoted for these repairs hasn't got a clue and is covering his ar*e with all thes 'possibles'

Find someone else who does know what they are talking about. It does take 5 mins to take off the plate HE to check that first. The blockage would probably be on the primary side rather the the domestic water side, so the scale inhibitor is either working or irrelavant.

 

[boabcelt]

This might sound daft because its so simple, but a common cause of system pressure rising is a filling loop left partially open/passing. Worth a check before going to the expense of renewing the expansion vessel. I agree with the guys that whoever quoted for these parts was just going for the' belts and braces' approach. Either they dont know how the boiler operates or they are trying to fleece you!

 

[andyboiler]

Boabcelt and others, thanks for your help, I could have done with this years ago. I do think that my boiler has had it though, because since the weekend we have had no hot water, and the overheating error code 02 has come up several times, whenever we have used the hot taps. The latest guy did say about the filling loop partially closing. I have turned off the boiler now, and we are relying on the local leisure centre for showers!!!
We live in a notorious hard water area, and everyone suffers from similar problems.
As the boiler is 10 years old, does anyone think that I should replace it? Is £1700 a good price for a replacement boiler plus a powerflush?
I am currently unemployed, and this is like a hammer blow to me - maybe I should retrain as a plumbing and heating engineer

 

[andyboiler]

More problems. I have switched the combi back to the centre position - off, reset - because the 02 error message (overheating) came on. That was two days ago, and the thing is still flashing, despite being switched off. Is the display knackered, because the boiler is not firing up? Is this a really dodgy/dangerous situation? Is there a chance of a gas build up?
This has got me really worried, and the new boiler will be installed on 14th July hopefully.
Please help!!!!!