Power Flushing Working Combi System

[EliteHeat]

I've been asked by a builder to power flush a customers system and put on new TRVs. It's a combi system with 7 rads. I have never had to flush a combi system before, with the boiler in situ, so could use some advice.

Do I ...

1) Take off one of the rads, run system up to a reasonable temp, switch off and flush - this has the advantage of flushing the pump and HE

2) Drain system and temporarily isolate boiler and fit pump valves to the flow & return pipe work - this has the advantage of performing a full-bore flush and dealing with all rads in place. Disadvantage is lack of heat from the boiler

3) Inject some X400, run system for a few hours at max temp and then do either (1) or (2)

TIA

 

[HarrogateGas]

Depending what boiler it is you can take the pump out of the boiler.

 

[DP]

Have done it regularly.

Fit 22mm tee flow and return.

Fit a stub of 22 pipe and pump vave to branch

Fit power flusher

Flush each rad using rubber mallet

Finish off by chemical cleanse with Ferroquest with boiler on line.

Flush each rad with boiler working, drain partially open and filling at equal rate till water flows clear.

Go to next rad.

After final rad, remove stub and install internal stop end (takes place of olive)

Finally treat with X100. Do not like MB1

Cold flush does not work.

Other alternative is to drain and fill repeatedly until drain water is clear.

 

[EliteHeat]

Have done it regularly.

Fit 22mm tee flow and return.

Fit a stub of 22 pipe and pump vave to branch

Fit power flusher

Flush each rad using rubber mallet

Finish off by chemical cleanse with Ferroquest with boiler on line.

Flush each rad with boiler working, drain partially open and filling at equal rate till water flows clear.

Go to next rad.

After final rad, remove stub and install internal stop end (takes place of olive)

Finally treat with X100. Do not like MB1

Cold flush does not work.

Other alternative is to drain and fill repeatedly until drain water is clear.

Cheers for that

 

[corgiman]

or invest in a pump adapter for your machine, we did and it works a treat for combis it do

here is an example

http://www.kamco.co.uk/PFaccessories.htm

http://www.fernox.com/index.php?cccpage=whats_new

 

[simond]

We would cap off the boiler flow and returns on a combi, can't risk getting sludge inside. Just as importantly, we can't risk the customer inferringwe put sludge inside.

Answer is to use a powerflusher with a heater; it's a £300 bolt in option on the Norstroms and all our machines have one fitted for exactly this scenario. Probably 20% of boiler replacements are where the heat source is beyond repair, the heater is very useful.

We use the Kamco pump adaptor with the Norstrom Powerflusher if the combi boiler is to be scrapped and replaced, very convenient little tool.

 

[ChrisR]

Major point of powerflushing a combi system is to flush the boiler! Flushing the rads alone would be daft, with or without a heater, which would only reduce the time a bit.
Make sure you run on HW (gas on or off) to circulate chems round the dhwhe primary.
If a hard water area think about the secondary side of the dhwhe too.

If you can inject something like Fernox HD Restorer (more effective than X400) and run it for a week first, so much the better.

 

[EliteHeat]

This is going to make me sound like a complete idiot but I do actually have the Kamco pump adaptor. It's never been used and is still in its box.

The reason that I haven't used it is 'cos I was always worried about the pump leaking when I replaced the motor and then I just forgot I had it!

Anyway, assuming that I used the pump adaptor, how do I actually run the system with the CF30 attached? it's going to go down to atmospheric pressure.

I'm missing something here aren't I?

Your answers will clear up a number of puzzles for me - he he

 

[sooey]

The kamco pump gives about 1/2 to 3/4 bar pressure through the combi, if that's not enough to let it start you would have to bridge out the low pressure cut off temporarily. Make sure that the jubilees on the pump adaptor are nipped up though and protect all the electrics in the combi, the first time I used mine one of the clips dripped even though it was brand new.

 

[Agile]

Still digging up five year old postings to reply to?

 

[corgiman]

Still digging up five year old postings to reply to?

better late than never tony

 

[mickyg]

even have a trademark on their name.

well thats swung it for me, where do i sign ?