Power flush - do I need to or Not?

[JAJK]

Hi,
We have a maintenance contract with Viessmann on a Vitodens 100 WB1A which to be honest we've had nothing but problems with since the installation 7 years ago. The pump inside the boiler needed replacing and whilst the engineer was on site he tested the boiler by running the hot water tap. The boiler was reaching temperatures of 82 degrees (though the water was not that hot) - the heating is working fine with no cold spots on the rads. The engineers says that the system needs a power flush as the boiler overheating is a clear indication that there is sludge/debris in the pipes. He has taken a water sample for Fernox to analyse and confirm his suspicions (which to be honest did not look dirty to me).

Does what the engineer is saying make sense that sludge could be affecting the DHW system? I suspect if Fernox come back with a recommendation to power flush my contract with Viessmann will effectively be null and void until it is done

I know that you pay around £300 for a powerflush. If I need to have one what stipulations would you make to the plumber doing the job

Any comments or suggestions would be welcome

 

[Dan Robinson]

"Stipulations"?

Are you having a laugh?

 

[Dan Robinson]

Double post.

 

[ianmcd]

the boiler you have has real problems with dirty systems and by your description it does sound as though this is indeed your problem, I am not a great lover of power flushing as although it can be good you are at the mercy of whoever carries it out, a proper chemical flush by an experienced engineer would probably bare more fruit, the plate heat exchangers on these block very easily

 

[Agile]

It sounds as if the plate HE is rather blocked.

The trouble is many just say that a power flush is needed when its actually a chemical clean of the s=affected boiler parts.

Not helping either that most people who do power flushing do not do any cleaning work on the boiler!

Tony

 

[JAJK]

Speaking to Viessmanns technical help they reckon that the boiler itself can be flushed rather than a full system powerflush. The boiler can be put in service mode (which puts the diverter valve in the middle) and the boiler itself cleaned. Still waiting to hear back from Viesmann about the results of the water sample they've taken

 

[Agile]

That's quite right!

BUT, few will just power flush just the boiler!

Furthermore if these is loose dirt in the system which has got into the plate HE then there will be more waiting to block it later!

Tony

 

[JAJK]

That's quite right!

BUT, few will just power flush just the boiler!

Furthermore if these is loose dirt in the system which has got into the plate HE then there will be more waiting to block it later!

Tony

Cheers Tony,

The Viessmann engineer has been today to fix a leak from the boiler. Whilst he was here he cleared out the HE which he said didn't look too bad but there were metal particles. He was honest enough to admit that this is not a good boiler and it does not tolerate any level of **** in the system and he advised that if I can live with it until the Spring he would get a new boiler and get the power flush as part of the install.

 

[Agile]

He was honest enough to admit that this is not a good boiler and it does not tolerate any level of s**t in the system and he advised that if I can live with it until the Spring he would get a new boiler and get the power flush as part of the install.

Are you suggesting that he is going to replace the boiler at Viessmann's cost?

Tony

 

[JAJK]

Are you suggesting that he is going to replace the boiler at Viessmann's cost?

Tony

No - he said given the history of the problems I've had I might get some discount of a new model. He was just being honest about having to pay for the powerflush + ongoing costs every winter of repairing a poor bolier.

I'm not sure I would trust another Viesmann though - I've probably paid more for repair costs since 2006 than the original boiler cost me.

 

[Agile]

Check carefully before you rush into paying for a discounted boiler.

I have heard of people taking a discount and still paying more for a boiler than the installer could have got it for!

Generally on a clean system they have been fairly reliable after the grey or red ignition unit had been replaced.

Tony