powerflushing CH by the patented DIY method

[Stephen]

Hello,

Someone once posted their patented DIY method of power flushing but I can't seem to find that post anymore.

I understand that it involves connecting a hose to the CH and opening each rad. in turn. But do I need to open the lockshields fully, or can they be left balanced?

How do you fit the hose? I was hoping to slide it onto the 15mm pipe and secure with a jubilee clip, but then I found that the bore of the hose is not wide enough.

Thanks, Stephen.

[John]

I found that by heating the hose I was able to connect it onto a 15 mm pipe with a jubilee clip. On the other end of the pipe I fitted a quarter turn isolating valve with a compression fitting onto the pipe - the other end will readily screw into the radiator tail boss (in my case with older radiators I fit it to the top bung - where the air release valve is.) Open the lockshield (make a note of how many (or degrees if less than a full turn) turns is needed to shut it off)

[Stephen]

Thank you for clarifying that the lockshields must be fully open.

I am hoping to connect a hose to either side of a rad that I am taking off.

Am I right to think that I need to isolate the boiler, possibly by isolating the pump? Is this to prevent the water short-circuiting the radiator and going through the boiler or is it to protect the pump: would it be damaged by being turned by the water?

How do these CH cleaning additives work? Is it best to power flush before they are added to clear the "loose" sludge and then add the additive and repeat? Would the additive otherwise be wasted on the loose sludge?

Finally, do you also close the HW loop?

Thanks, Stephen.

[Spamlet]

Take the rad into the garden before you take off the end 'taps': that black goo sure does mess up the carpets...

S

[Stephen]

Hello,

I connected a hoses in place of the tails of one radiator and flushed the radiators one at a time. I had some sludge from two of the oldest radiators but the water seemed pretty clear from all the others. I gave them a tap at the same time to knock the sludge loose.

I was going to add a chemical cleaner and then repeat a week later. Should I rebalance the CH before running the cleaner or should I leave the lockshields fully open? I'm thinking balancing balances heat loss rather than flow doesn't it. OTOH having the lockshields fully open will not balance flow either, so I guess it's a no win situation.

Is there any mileage in connecting a hose to the top of each radiator and flushing it? Presumably the current method just flushes the bottom of the rad. but OTOH isn't that where all the sludge is?

Where does a powerflush machine connect? Do you fit it to one fixed position or take it round each room and connect to each rad in turn?

Thanks, Stephen.

[John]

If you are disconnecting the radiators - then why not take them off the wall and take them outside? I have top bungs on my radiators and I always wash them out when removed for decorating - top to bottom - but as I always use a system additive I have never encountered anything other than dirty water. Washing the convection channels at the back is also useful. Amazing how much dust builds up. (if your rads have them)

[Stephen]

But by powerflushing can't you wash all radiators by only taking one off? That's a lot less work than removing them all and besides cleaning them individually wouldn't clear the pipes between the rads.

I don't want to have to remove all the rads because I am not decorating all rooms at once and there's the danger of dripping black water over the carpets! Especially the upstairs rads would involve a lot of walking through the house and lots of potential for dripping!

But surely the dirty water is sludge?

Thanks, Stephen.

[John]

Weak tea colour. No visible solids.

[Stephen]

How strange.

[Rod]

Is it? Quite a good description of what ours looks like. But I'd probably say 'very weak, no milk'. Have ensured that the system was flushed (several times when various work required it) and treated for many years now.

[John]

I don't use milk in my tea or coffee! (so I never thought to qualify my comparison)

[Rod]

Because it matched our CH water so well, it wasn't difficult to guess that. (I take less than a tsp. in a large mug - which doesn't make much difference. :-) )

[Dave Plowman (News)]

I recently replaced my boiler which had a cast iron heat exchanger. The inhibitor was 5 years old - I keep a log of what's been done to the CH system. I watched it drain and very little in the way of solids came out. Refilled and added Fernox cleaner and ran for a week and re-drained. No solids.

I changed the rad in the bathroom for a towel rail and took that opportunity to hose through the old rad for use elsewhere - again, very little in the way of black water or solids. The old system was open vented.

To me, shows the benefits of using inhibitor.

[Jon]

When I flushed my Dad's radiators a couple of months back, I put old curtains under the rad before I took it off. When I lifted it off the brackets, I flipped it upside down and walked it outside.

No dripping black water onto the carpets.

[Stephen]

So is this colour the colour of the inhibitor or something entirely different?

[Rod]

From memory, the inhibitor is very pale - I'd suggest not dark enough to do anything significant. So possibly the soluble material that was not fully cleaned out and/or what the inhibitor doesn't quite inhibit (but must be at a vanishingly low level).