Power Flushing - Yes or No

[Heat Kent]

Help & advice for a newbie RE power flushing...

From what I can gather there is an "associated document" to Part L of the Building Regulations, called the Domestic Heating Compliance Guide, which states that "central heating systems should be thoroughly cleaned and flushed out before installing a new boiler" (It’s a pretty boringread). With this being a guide and considering the use of the word “should” I assume there is no “legal” requirement. However, boiler manufacturers require you to follow this guide in order to validate their warrantee? This is a flush and clean, but not necessarily a power flush right?

However, if you type into Google “minimum requirement power flush” you’ll see that there are load of Power Flush companies who have the standard line “Power Flushing is the new minimum standard” implying that it is something you must have done.

I have been installing boilers (with someone who has his gas) and we simply drain the system, put a TF1 on the return, put a lime scale reducer on the cold feed and add an inhibiter when we refill. I’m new to plumbing and am finding all of your advice and help very useful and want to make sure I do everything correctly going forward. So please jump in and give your views, experiences and opinions. I’m leaning towards buying a Kamco CF90.

Thanks in advance.

 

[Heat Kent]

It would also concern me using power flushing on microboresystems and plastic pipework with pushfit fittings. If the valves/fittings areold and corroded will they start to leak if interrupted?

 

[Mike Jackson]

Just draining, fitting a TF1 and adding inhibitor is insufficient. The bare minimum required is a chemical cleanse.

 

[Heat Kent]

Just draining, fitting a TF1 and adding inhibitor is insufficient. The bare minimum required is a chemical cleanse.

That seems to be the general consensus, but do you do thisseveral days prior to flushing and let the system run or in and out in one/twodays? Also do you power flush or just rinse through? Can you power flush plasticpipes?

Thanks

 

[stratplus]

A lot of council boiler changes are done in a day. Y plan out, combi in. A case of drain system, do swop then add inhibiter and fill. No time to power flush and not expected to. (So I've heard).

 

[JAH HEATING]

A lot of council boiler changes are done in a day. Y plan out, combi in. A case of drain system, do swop then add inhibiter and fill. No time to power flush and not expected to. (So I've heard).

Most leave x400 in the system an then have a different engineer come round, drain it an refill with x100

 

[stratplus]

Not on the councils I've worked for. There'd be x400 in the system for months with the access rate being so poor.

 

[jase158]

the fact is that he is right, there is no legal requiremen in the building regs, but it is a manufacturer requirement, which then becomes a legal requirement as manufacturers instruction have more power then british standards so should be done.

But there is no clear fact on what sort of cleanse it is. could we just put x800 in the f and e? could we do a full powerflush?
what precedents a cleanse is debatable but we all know that not many people do it due to time and cost, but we should all be doing it.

 

[tamz]

It is not a manu requirement either as they point you to BS7593

Here is what it says there if you don't have it

5.2 Cleansing and flushing methodologies
There are three cleansing and flushing options, one of which should be applied.
1) Mechanically-assisted powered cleanse and flush (powerflushing) (see 5.3).
2) Mains pressure cleanse and flush for sealed systems and open-vented systems with the feed and vent temporarily capped-off (see 5.4).
3) Cleanse and flush using gravity, with the assistance of a circulator pump (see 5.5).

Powerflushing is most effective as this produces a more thorough clean, but the boiler manufacturer’s instructions should be checked to
establish whether powerflushing is acceptable. Powerflushing is the most effective method of cleansing existing systems, especially those
containing a high level of black magnetite sludge.
With all methodologies, reversing the flow will help to remove debris which might otherwise remain trapped.
An appropriate cleanser should be chosen. (Refer to manufacturers’ instructions.) The following factors should be taken into account:
a) the reason for cleaning;
b) the system materials, e.g. aluminium;
c) the age and condition of the system;
d) any specific problems identified;
e) any local restrictions on disposal of the effluent.
Hot flushing is more effective than cold flushing, but the cleanser
manufacturer’s instructions should be followed.

 

[Blake]

try sticking an extra £300 - 400 on your boiler quotes for a powerflush and see how many jobs you get