Hose pipe vs power flush

[judder]

So, from 4 out of my 10 radiators I get no heat, and I mean none. The pipe is warm up to the TRV, but the rad cold (and I've tried new TRVs). I'm not a plumber, but had a fiddle with the output valves around the system (attempting to balance it), but it made no difference and I've returned all settings to how they were. Guessing the system was full of rubbish, I drained off some water, which came out black. Nice.

I'm thinking to remove each of my radiators, taking them in turn into the garden, sticking a hose pipe in one end and waiting until clean water comes out of the other. Aside from the addition of inhibitors and cleansing of the pipework connecting the radiators, tank and boiler, does a power flush have any further advantage over my proposal, making it worth ~£300?

 

[simond]

Not really. I hope you don't have white carpets.

 

[judder]

Thanks for the reply. No white carpets, just cheap, horrible, dirty blue ones left by the previous owner. New ones after the heating is sorted.

 

[spudkey]

circulate some cleaner in system beforehand and while each rad is of connect hose to valves to flush pipework

 

[ChrisR]

"Just" a hose will only find one way through the rad. What you need is to clear the vertical channels.
2 people needed unless you use bungs:
Go into the garden with the rad

DO

• this :
  Hold the rad inverted and fill it about 1/3rd full.
  
  Cover the ends and invert the rad, and back
  Repeat half a dozen times
  tip the contents out and hose through until clear

UNTIL you don't see any more dark water coming out of the rad (tip it out over something white, to see)

 

[judder]

That's very helpful, thanks. I'd often wondered about the design of radiators, whether the water had just one route to follow or the possibility of several in parallel. Thanks.

 

[ChrisR]

Just a thought - if your pipes are microbore (10mm or less) they can block too!

 

[judder]

Not sure about the pipe size, but when I loosen the connection at the valve, water comes out quite freely, so I'm guessing (hoping) they're not blocked.

If I were to add a chemical cleaning agent, I assume I just put it into the header/expansion tank, is that right? If so, how long does it take for the water in the header/expansion tank to run through the system? Also, in my loft I have two tanks, a big one (which I think takes the expansion pipe) and a little one. What's the little one for?

Cheers.

 

[billy bob]

Power Flushing is over rated, nothing wrong with traditional methods of flushing, hose etc