Power Flush a Block Micro-bore System

[glendower]

Hi everyone

I have been asked to powerflush a blocked microbore system that has 6mm 8mm and 10mm pipe work. The history behind the blockage is that another plumber drained down the system to fit thermostatic valves to two of the radiators. When he re-filled the system and when he turned it on the boiler cut out after a minute or so. I was told the flow pipe got very hot and the return stayed stone cold. When the boiler had cooled down it was turned on again and the same thing happened. This was done apparently a number of times.
My thoughts are to connect the powerflusher onto the system where the pump is fitted, which is on the return pipe, close off all the radiator valves and turn on the powerflusher with the flow reversed in the hope that this will clear the blockage. Then proceed with normal powerflush.
Sorry for a long first post any advice/tips would be appreciated.

 

[Gray0689]

Are you sure it's blocked and not just airlocked
I'd try and clear with mains first
Shut off all rads and back fill with mains
Never tried with a powerflusher may not be powerful enough

 

[mikegas]

Is the pump running?

 

[CES]

You wont clear a blockage with a powerflusher. That works using high flow, not pressure, as said Id use mains if you're sure its not just airlocked.

 

[glendower]

Thanks for the replies Yes the pumps running and the previous plumber bled all the air out of the system even putting an additional air vent at the highest point on the system

 

[glendower]

Thanks Grey0689 and CES I think I will close off radiators, remove feed & expansion tank, loop vent and feed pipe together, take out the pump and connect mains water and flush it through.

 

[Gray0689]

Sounds like a plan mate

 

[jase158]

I would be extremely worried about flushing 6mm.
Perhaps a good idea to put cleaner in for a week, with system running and drain down, see if this clears.

The kamco training told me that if you are flushing microbore then need to use twice the amount of chemical so that it breaks it up more.

Have you told customer that you will give it your best but if no joy, you can not be held responsible as poor system and previous plumbers handy work.
Worst thing when you spend all day doing everything you can for them to say, you havent fixed it so you aint being paid, even though you have done everything you can think of, then receive a phone call week later to say another plumber did it in 2 seconds.

well if i hadnt eased it first he would of never done what he done, lol

 

[stevetheplumber]

id drain it and fill it with a few gallons your choice of flushing agent and leave it running for at least a week prior to flushing to give it time to work its hard to belive anythingwould totally block the whole system so id try a new pump first as well ot unkown for old ones to fail after a drain down

 

[FD Powerflow]

Wolverhampton is a hardwater area, the best advice I can give you is to get some DS40 a powdered powerflushing chemical, mix half the box in 10 litres of water inside your flushing machine till the water turns red, connect up via the pump, either isolate or connect the f and e together and run the powerflushing machine for a good three hours, changing direction every 20 mins. DS40 dissolves scale using citric acid and will allow flow to the blocked section whereas most other cleaners are simply dispersants designed to move sludge provided there is a flow to it.

 

[glendower]

Yes I agree putting in cleaner and running for a week would be ideal but the systems not running. You turn the boiler on, it runs for a few minutes overheats and turns off because there is no circulation. The pumps working there is a blockage stopping the water from circulating.

 

[glendower]

id drain it and fill it with a few gallons your choice of flushing agent and leave it running for at least a week prior to flushing to give it time to work its hard to belive anythingwould totally block the whole system so id try a new pump first as well ot unkown for old ones to fail after a drain down

I suspected the pump but it does appear to be running and the previous plumber said the same so the customer does not want to change the pump. He does accept that if I can get the water circulating with the powerflush machine then a new pump will be needed. The previous plumber does not do powerflushing but he did recommend someone who turned the job down saying he didn't do microbore. I like a challenge and if I succeed there is a chance of more work. So I need a good result.

 

[CES]

Ive used a foot pump to unblock 8mm pipes before, can be a bit messy sometimes, especially when it clears rapidly!

 

[glendower]

Ive used a foot pump to unblock 8mm pipes before, can be a bit messy sometimes, especially when it clears rapidly!

Sounds interesting where/how did you connect the pump. Woo a bit messy, customer as some nice carpets lol

 

[CES]

On an 8mm system if a rad is not heating I drain down, disconnect the rad and attach the foot pump. 8mm usually is a snug fit for a standard pump nozzle and I give each side a couple of pumps to clear it. Sometimes it pressurises up so I have a tee piece cut in with a tap so I can relieve the pressure into a bottle. It works most of the time, if it doesn't then its usually a cut out job.