Power Flush old boiler or with new boiler

[jp1*]

Hi

I am having a new boiler and my old radiators replaced by new ones.

Should the power flush be done with the old boiler and old radiators or is it better to remove the old rads (with sludge) and then do the power flush with the new boiler or old boiler (installer wants to do it with new rads and new boiler)?



Thanks,

 

[Calmore]

I think there's no point power-flushing the old rads; all it will do is disturb the sludge which will then be distributed throughout the rest of the system that you are keeping.

Personally, I'd have the radiators replaced, power-flush to remove any crud in the pipes then have the new boiler installed. I'd then clean with a proprietary cleaner to remove any residual flux and then fill with inhibitor.

I'm sure others will have differing opinions.

 

[Agile]

When new rads are fitted then the specific flushing chemical like Sentinel X300 should be used.

Old dirty rads need X400 or X800. But if old rads are to be removed then that's pointless as the new rads need flushing as well although many installers don't bother.

Tony

 

[Jackrae]

Think you'll find boiler manufacturer specifies system should be flushed BEFORE boiler is installed. After all, what's the point of flowing crud through a clean boiler heat exchanger and possibly damaging both it and the pump ? If your plumber wants to instal the boiler before the flush i surmise he is simply looking for avoiding having to install a dummy loop to act as the boiler circuit.

 

[jp1*]

Is this applicable even if the radiators are being changed at the same time?

 

[Jackrae]

Would have thought so considering your pipes might be full of debris etc

 

[jp1*]

Brilliant - they are doing the flush once the new boiler and rads are installed...

 

[dilalio]

Yes, but they might be isolating the new boiler from the system when they do the flush... It's what we do!

And what you should do. Madness to send ****e through a brand new hx!

 

[jp1*]

Ah ok I will check - that makes sense!

 

[jp1*]

So what are the best/recommended system cleaner / inhibitor products to use?

I see Sentinel x300 was mentioned - what about the inhibitor?

I think they are going to use some standard trade products.

 

[dilalio]

It's up to them really... As long as they get it clean! They'll probably use one that is made by the same ppl as their flushing machine, bought in 5L container.

 

[jp1*]

Well I've seen 2 bottles marked 4trade and they are only 500ml each (one cleaner and one inhibitor)....

Spending a lot on the install and want to be sure it's all right.

 

[simond]

If they are using 4Trade chemicals, they stood in the merchant and asked them for the cheapest shyte possible. Most installers with a care about the finished article would use a brand such as Fernox or Sentinel.

Regarding the powerflush, onlly in the very worst cases will any muck be in the pipes, it'll mainly be in the rads and boiler. This is because the water velocity is high in the pipes, and carries it along to the place where the speed lowers, like a radiator, whereupon it drops to the bottom, which is why rads are cold in the middle. Double panel radiators are particularly dirty because the water is moving half the speed of a single rad.

If you PF with the old rads you will move it all around.

 

[jp1*]

I think I will go and buy a branded cleaner and inhibitor myself then!

How many litres of each would I need?

Got 10 rads and 2 heated towel rails.

 

[Agile]

The 500 ml bottles are adequate for the typical system.

I have little regard for the installers who use the cheap chemicals. Whilst we cannot do any meaningful tests on them the simple solution is to buy the market leaders, Sentinel and Fernox and trust them to be providing us with a premium product as they say they do.

Tony