Flush or not to flush

[madge1]

Hi

We're half way through a major extension, with a new boiler/HWC etc installed.

Some of the old rads were cold in the middle etc; all indications a power flush was needed.

We've a new Worcester 37CDi installed. The heating engineer didn't power flush on installing the new boiler, but added vast amounts of Sentinel, and to be fair the old rads are much better after 4 weeks (but still take an age to heat up). I'm assuming the Sentinel can only do so much though

He's coming back next week to install the UFH in the new area, and finish off, so i've a couple of questions for him.

Should I insist on a power flush? - the 5 year warranty for the boiler implies a flush needs to be done, but doesn't differentiate (as far as I can tell) between a power flush, and a chemical flush. When I asked him he got all defensive, and said 'we're a reputable company et al'; they are accredited Worcester installers, so I assume he knows what he's doing.

We've three 'bad' rads. Should I replace them (they're ~25 years old), or have a power flush. Or indeed both? Or just clean them through with a hose, and then see whether we need the power flush/new rads.

Just don't know what to do for the best (and to make sure maintain our warranty!)

ta

 

[Madrab]

Most boiler manufacturers insist on a flush of a system prior to their boiler being commissioned to validate the warranty. Especially on an existing rad system. Even then to ensure maximum efficiency then it is always prudent to ensure the system is clean before a new boiler is installed, however that is achieved. A magnetic filter should also be installed IMHO.
If they're accredited WB installer then they should register the boiler and confirm the warranty and period with you. If they are accredited then the warranty can be extended to 7 yrs.
I'd clean out the old rads and see if they come back to full working order. This can sometimes cause problems with pinholing depending on how corroded they were initially. Wouldn't know until you checked them. I'm a great believer in "if it aint broke, then why fix/replace it"

 

[madge1]

Thanks

But is that a power flush, or a chemical flush? That's what I don't understand...

We've got the warranty - all been signed off with Worcester. Just don't want to have issues down the line and then worcester say 'Sorry, but...'

I think the plan is to see if we can fix the old rads first; just don't want to be pee-ing in the wind!

 

[Madrab]

As I say Madge, whatever it needs. Most power flushing use a chemical cleaner anyway. That can be introduced say the night before the job is done. A power flush would give a more effective clean if the system is that old though IMO.
I wouldn't worry about the future as that is covered by the fact that it's an accredited installer that did the job, therefore it would go back to him. I assume that is stated in the warranty anyway, if not then get in touch with WB and confirm if your concerned.

 

[kbdiy]

Just isolate and remove the suspect rads, take them outside and flush through several times with a hose until the water runs clear. Then refit and see if the cool areas have improved. Simples

 

[madge1]

Many thanks

I'll see what he says next week; to be honest it's mostly his son who does the work and he does the complaining... The rest of the work has been excellently done, so I don't really think they're cutting corners here, just want to be sure.

 

[Agile]

Te system needs to be clean!

How that is achieved is down to the installer.

In my opinion the installer should be held responsible for sludge issues. Most don't answer their phones once they are paid!

Of course many customers try not to pay and don't answer their phones either!

Tony