My Vokera Excell 80 SP has gone crazy!

[ollietaylor]

Hi All,

I have read these forums before and they have proved to be informative & helpful so i'm hoping somebody can help me!

There are afew other posts on here detailing a simular problem but nothing exactly the same so please read this all the way through.

The other day my DHW started to go hot and cold. I had this problem before and ended up chaging a divertor valve which fixed the problem. It was like this for about a day and before i had chance to phone British Gas, who i have cover with, the DHW died all together. Usually i have to blast the hot tap to get the boiler to fire, then i turn it down and it keeps lit like it should to heat the water. However as from yesterday it reaches a certain temp (55-60c) & then it cuts out leaving the water cold! despite the cold water the temp. gauge stays where it is (55-60c) for about 20 minutes after despite turning the water off. At this moment the water doesn't even get hot but the gauge still rises!?

Along with this problem my heating also began being tempermental. If my CH was on, or if i tried to turn in on during or soon after using the DHW the temp gauge still reads high but the heating would just stop to account for the DHW use and not reactivate. However the CH is fine if i use it about an hour after calling for DHW.

Also the pressure on the boiler keeps dropping, if i try to turn it up a smidge although you can clearly hear when i stop adding pressure the gauge continues to rise slowly and smoothly untill it gets to about 2.5 bar.

Anyway, i called out BG to have a look. The guy said he had fixed the heating problem, it was due to a sensor being lose which he reattached and the fact that i had leaned my old back door against the Flue. As for the DHW he said it needs a new Plate Heat Exchanger, but depsite this he says it's an old boiler and should really be replaced (This isn't an option as i'm planning on moving house in a few months). The boiler was clearly neglected by the previous owners but since i have been there i have had it serviced regularly and it's been checked over by a few engineers for various issues, all of which have been fixed.

So, BG said that as they suspected the Heat Exchanger was blocked by sludge it was not covered by my cover thing.

They wanted 2-3k for a new boiler or £3-400 to replace the Heat Exchanger so I told them i would sort it myself.

I have ordered a new HE online for £55.00 and have got a reliable Corgi engineer coming to fit it on Friday (2days) for me.

Can anyone let me know if they think the problem lies elsewere and if there is anything i should ask my eng. to look at (DP, AGIlE and SCATMAN seem clued up on these boilers so maybe you guys could help?)

If they think the old HE can simply be cleaned instead of replaced?

If it could be cleared by powerflushing the system?

Any tips, help or advice would be like gold!

Sorry for being so longwinded about the whole thing!

Many Thanks

Ollie

 

[bengasman]

Unlikely to be the plate exchanger as this has no influence on your heating. Get bg to tell you in writing what the problem is and why they refuse to repair it.
2.5 bar is way to high, especially when the system is cold.
is the heating still working correctly?

 

[DP]

I would start by servicing the boiler to restore boiler functions to what they should be followed by investigating if any defects remain.

My suspicion is lack of proper service. To some people service is carried out with a feather duster. Other claim a service is detrimental as it is likely to cause more problems (usually maintained by those who do not understand boiler operation in my opinion). Then you have those that will always want to replace the boiler, I wonder why.

 

[petit_pablo]

Sounds like its its blocked somewhere to me and the boiler isnt clearing the heat.
BG chap blatently didnt want to do the job! I do the hw heat exchangers for £108 if they are on 3* and the have known sludge problems. Often do the 1st one free.

Also sounds like the expansion vessel might need repressurising as well

 

[lor]

i had leaned my old back door against the Flue. [/quote]

 

[ollietaylor]

The heating works fine if you don't attempt to use the hot water while it's on. Also the heating plays up if you try to turn it on just after i've called for hot water.

So you suggest i get a full service done? I have one due soon as part of my BG contract anyway. I will get the Heat Exchanger changed and see where that leaves me. I've got a feeling it still won't work. I'll re-post to let you know.

Thanks for your advice lads.

 

[DP]

I doubt BG will do a full service on the boiler. Am constantly coming across boilers covered by such contracts where the customers have not been able to resolve the problems. On these boilers, survice is normally well overdue.

Equally, BG are taking on contracts where householders cannot get independent Heating engingeers to carry out competent repairs (wether their engineers can is another discussion point)

Had you been in Glasgow, would have offered a demonstrated repair/ service.

 

[ollietaylor]

DP - Do you sugggest that i get the guy who fits the heat exchanger to service it for me? Does this involve getting a service pack? Is there a certain type of service it requires?

Do you think that the nature of my problem could be something to do with the fan? Alot of peoples problems have been fixed by cleaning the fan, just a thought?

Thanks

 

[DP]

I would get someone who knows boiler operation. Change nothing until it has been proven to be defective. Assume nothing. To start changing components based on assumption is an expensive game.

If your engineer can demonstrate boiiler operation to you and also is comfortable with you present while he works on the boiler, he is your man (or woman)

 

[bengasman]

sounds about right

 

[ollietaylor]

Hi, just to let everyone know that all my probelsm where sorted when an engineer (not BG) changed the Diaphragm! He said this would have been his first point of call.