Combi 100 Boiler Lockout Problems

[Viniga]

Hi,

I have been lurking for a while trying to research how to fix my boiler, hopefully without having to call in a plumber.

First what I know:

The boiler is a baxi/potterton Combi 100. It is now 7 years old.
The system consists of 6 column style rads and one towel rad.
No bypass is fitted, the radiator closest to the boiler and the towel rad do not have thermostatic valves fitted, the others do.
I live in an area of soft water.

The installer did not correctly flush the system or add inhibitor, as a result iron oxide has built up in the system over time.

Problem:

System goes to lock out when turning on for the first time in the morning after a little bit of kettling. Once re-set a couple of times the heating will generally stay on without problem; however if hot water is run, the system will lockout after further kettling.

What I have Done:

Cleaned the system (fernox) and flushed it with mains water twice according to the instructions on this site. Added inhibitor on refill. I have double dosed the chemicals as due to the column rads the system seems to have more water in it than normal. Anyway this improved the kettling somewhat but I still have lockout.

These are the Things I am considering:


Keep cleaning the system out with chemicals.
Get a plumber in to Powerflush it.
Replace the pump or pump head.
Install a magnatec device.
Replacing the entire boiler!


As far as plumbing goes I am a novice, but willing... What should I do next?

Cheers,

Viniga

 

[baxpoti]

See other posts ref

Puma, pump and diverter valve problems

 

[bengasman]

Powerflush with fx2 is easily the best option

 

[Viniga]

Thanks for the replies, a couple of follow up questions if you don't mind.

How difficult a job is replacing the diverter valve?

I can't seem to find and installation/maintenance manual on-line for this - anyone know where I can get one?

I have a supplemental manual that mentions using the manual for the Combi 80.

 

[morris1977]

Hi Viniga,

I've got a combi 100 exactly the same age with exactly the same problem; did you find a solution to yours?
Any help appreciated, even if it was to call out an engineer - it would be good to know what to tell them.
Cheers,
Morris

 

[Viniga]

Hi Morris,

I have ordered a new pump and diverter valve - from researching the posts it seems the diverter is most likely the problem. My rough plan is to hire a power flusher, flush the system replace the parts and see what happens.

Cost at the moment is getting on for £250 including parts, power flush hire and cleaner and inhibitor. But then a professional power flush on its own is about £350...

I'll keep you posted but it might be a couple of weeks before I get round to it.

Viniga

 

[Viniga]

Hi,

Could someone please sanity check my planned power flush procedure please?

Bengasman mentioned using fx2 - but Kamco state the boiler as having an aluminium heat exchanger - so I plan to use Fernox FX3 for a week, then flush. Does this seem sensible?

Thanks,

Viniga

 

[Agile]

Hi,

Bengasman mentioned using fx2 - but Kamco state the boiler as having an aluminium heat exchanger - so I plan to use Fernox FX3 for a week, then flush. Does this seem sensible?

In that case then Keith was having a bad day when he wrote that!

Tony

 

[Viniga]

Hi,

I have now power flushed the system, installed a new diverter valve and a new pump. What a weekend...

Anyway, things seemed well until I got home tonight. Place was warm but boiler flame was not on. Noticed that it was coming on for a few seconds and then shutting off right away.

Any ideas?

Vince

 

[Agile]

Sounds as if its sludged up!

I did make a posting saying that the Kamco site only said dont use FX2 if its the "HE" version.

You then replied to say you would use it as yours is the standard efficiency!

It seems that yet again this mad Mod has been deleting perfectly innocuous postings just to feed his power complex. Probably mad Mod 10 who seems to be another one who gets drunk and become irrational.

Tony

 

[Viniga]

Hi Agile,

Sorry, I am a bit confused now... you posted something and it was deleted?

Anyway, are you saying I could have and should have used FX2? It was FX3 that I added to the system.

Cheers,

Vince

 

[Agile]

If your boiler is not condensing and the HE is made of copper then you can use FX2.

Its usually very effective but cannot be used on aluiminium.

Tony