DIY radiator circuit flush

coffeehound

Relatives' bungalow has at least one radiator blocked (with sludge, I presume) and a couple more partially cold, and the whole system is a bit slow.  So I will have a go at clearing the affected rads and maybe attempt to flush the whole circuit.  There are 17 radiators and the circuit is gravity fed.  There's a magnetic filter but I don't suppose they do a great deal.

What equipment, tools and materials would I need do you think?  They've got a wet and dry vacuum so hopefully that will remove sludge from disconnected pipe runs and radiators.  Is there a fitting to connect a hose adaptor to a radiator top fitting to allow rads to be flushed through with a hosepipe?

Any other advice much appreciated

FreeBear

I'd get some male & female blanking plugs. Drain the system down after running the system with some flushing chemicals, and remove one radiator at a time. Plug the end of the radiators with the plugs you purchased earlier. Take the radiator outside and flush it with a hosepipe and/or pressure washer after removing the plugs. The plugs should stop any black gunk coming out when you take the radiator outside and bring it back in.

Once all the radiators have been flushed, refill and add some corrosion inhibitor.

Jeepers_Creepers

Although more work, I think removing each rad in turn will give more success - then you'll know it's been flushed through properly and the sludge dumped.

Connect hose to one valve end, and thump the rad repeatedly, especially around the bottom-middle. Keep an eye on what comes out - if you can see obvious increases in black stuff when you thump it, you'll know it's working.

It'll be interesting to see how well that works with the blocked ones in particular.

(If the rad tails disappear down through a suspended floor, good chance there will be enough movement in the pipes to allow you to remove the rads quite easily; shut off both valves, pan under one valve and crack open the joint. Bleed to allow air in. Disconnect both valve/rad joints fully - pans under both! See if valves can be pushed aside the required few mm, and lift rad straight up by less than 10mm to disengage it from the rad brackets. Lift off fully.

If you manage that, then you should have removed the vast bulk of sludge - the rest will be coating the pipes.

The fitted filter should be collecting sludge - in fact, if the system is really that blocked, that filter should be full! Has anyone checked? As you suspect, tho', it won't collect it all. If you want a proper DIY solution, then ask them to buy a Magnacleanse on eBay - it'll cost around £250, but they'll sell it on for the same amount afterwards - and temporarily fit that in place of the wee filter, adding a good dose of a strong cleaner like X800 - even a double-dose. Let that run for as long as Sentinel recommends (a few weeks?), and clean the filter every week or so, depending on amount collected.

When the collected sludge quantity falls off in an obvious way, then drain/refill/flush the system to get rid of the chemicals, refit the small filter and add inhibitor along with long-term 'filter aid' (a gentle cleaner that can be left in).

Phew - if you do this, you must love your relatives... :-)

(I have a Magna fitted currently to try and get rid - once and for all - the last traces of sludge in my old system - see photo).

bris

Part of the problem is the sludge can weld itself to the inside of the radiators and whilst chemicals can remove some of it for the filter to catch it doesn't remove it all.

The magnacleanse on in the picture comes with an agitator that fits to a drill with a chisel action, use that and the iron oxide is hammered off the inside without and damage to the radiator.

You do one at a time making sure only the one you are doing is the only radiator open. Once you make a couple of passes go look at the hoses, this is when you know you are getting somewhere. Close off that radiator and move onto the next.

Running a hose through a radiator you take off the wall does nothing to remove the iron oxide stuck firmly to the inside so dont waste your time doing that, and that takes a long time to waste.

Jeepers_Creepers

bris said:

Part of the problem is the sludge can weld itself to the inside of the radiators and whilst chemicals can remove some of it for the filter to catch it doesn't remove it all.

The magnacleanse on in the picture comes with an agitator that fits to a drill with a chisel action, use that and the iron oxide is hammered off the inside without and damage to the radiator.

You do one at a time making sure only the one you are doing is the only radiator open. Once you make a couple of passes go look at the hoses, this is when you know you are getting somewhere. Close off that radiator and move onto the next.

Running a hose through a radiator you take off the wall does nothing to remove the iron oxide stuck firmly to the inside so dont waste your time doing that, and that takes a long time to waste.

Fair point. But it would be a hose - and thumping... :-)

coffeehound

Thank you, gents, lots of useful advice there.  That's an impressive DIY flushing rig J_C, hope that does a thorough job for you.  Maybe I'll follow that advice if the first pass doesn't work.  Think the relatives of the bungalow have got a rubber mallett which might help with loosening crud, but not as well as the hammer action thing Bris mentions by the sound of it.

Jeepers_Creepers

I've had repeated issues with blocked P2P exchangers, due to small amounts of sludge coating it over a year or two each time. Even after fitting a Magnaclean Pro filter - which would collect sludge over time - I'd still get plates blocking up, so it's pretty clear that these small filters help, but don't catch everything.

Installing the M'cleanse was a simple connect-up-to-the-same fittings job, and has two large magnets, each one at least twice the size of the 'clean's, so at least 4 times the magnetic power! All very well if you don't mind it sitting there - mine's been in place for a couple of months now :-(

coffeehound

That's interesting; are you finding it is collecting much?  BTW yes, the bungalow has got a magnaclean though I've never opened it between services.  They get a service once a year on a maintenance contract which has been good to them, with the exception of flushing.

Jeepers_Creepers

When I first fitted the Magna Pro (the wee one) along with a dose of X800, yes, a lot of sludge was collected within a week or so - I recall it was almost a half-inch thick coating. That rapidly fell away until I would only check it every few months, and then it would have, ooh, 1/8-1/4  inch on it each time, as I recall.

I thought I had it licked at that point, but there was seemingly still enough going around the system - which the Mag wouldn't catch - to allow the P2P exchanger (which does have pretty fine channels in it) to become coated after a couple of years - very annoying.

That's why I tried the large M'Cleanse machine - it doesn't matter that it's sitting there as this is 'my' wee room...

Whenever I check this unit - every couple of months - I find just regular 'rings' of sludge collected on the magnet (obviously where it's at its most powerful), so not a lot at all.

Bludy P2P still blocked up a few weeks back... :-(

Your relative's filter has not been checked at each annual service?! Jeepers - I bet it's near-blocked!

That's the first thing to do - and it'll give you an idea of what the system water is like. Are you able to do this? And report back?

(Boiler switched off. Close off both valves to the filter. Slacken the bleed screw on the top to release pressure - only a tiny dribble will come out. Use the large plastic spanner to undo the top - try and support the filter body so as not to apply too much turning force on it and the pipes. Lift off lid - to which the rod magnet is attached. Wipe clean using paper towels - after taking a photo :-). No need to drain the filter body UNLESS you are adding chemicals (I use a short flexi pipe as a syphon). Refit lid, screw down hand-tight only, and perhaps an extra 'tweak' (don't do it down tight, but just check it ain't leaking). Bleed key sitting on screw as you open one valve slowly - as soon as water comes out screw (which it will quickly), tighten up. Fully open both valves. Jobbie jobbed.)

coffeehound

Jeepers_Creepers said:

That's why I tried the large M'Cleanse machine - it doesn't matter that it's sitting there as this is 'my' wee room...

Whenever I check this unit - every couple of months - I find just regular 'rings' of sludge collected on the magnet (obviously where it's at its most powerful), so not a lot at all.

Bludy P2P still blocked up a few weeks back... :-(

So does that mean the extra gunk isn't magnetic?

Jeepers_Creepers said:

Your relative's filter has not been checked at each annual service?! Jeepers - I bet it's near-blocked! 

That's the first thing to do - and it'll give you an idea of what the system water is like. Are you able to do this? And report back?

(Boiler switched off. Close off both valves to the filter. Slacken the bleed screw on the top to release pressure - only a tiny dribble will come out. Use the large plastic spanner to undo the top - try and support the filter body so as not to apply too much turning force on it and the pipes. Lift off lid - to which the rod magnet is attached. Wipe clean using paper towels - after taking a photo :-). No need to drain the filter body UNLESS you are adding chemicals (I use a short flexi pipe as a syphon). Refit lid, screw down hand-tight only, and perhaps an extra 'tweak' (don't do it down tight, but just check it ain't leaking). Bleed key sitting on screw as you open one valve slowly - as soon as water comes out screw (which it will quickly), tighten up. Fully open both valves. Jobbie jobbed.)

Thanks will give that a go when I'm next up

Jeepers_Creepers

coffeehound said:

Jeepers_Creepers said:

That's why I tried the large M'Cleanse machine - it doesn't matter that it's sitting there as this is 'my' wee room...

Whenever I check this unit - every couple of months - I find just regular 'rings' of sludge collected on the magnet (obviously where it's at its most powerful), so not a lot at all.

Bludy P2P still blocked up a few weeks back... :-(

So does that mean the extra gunk isn't magnetic?

That's a good question. And I don't know the answer :-)

I suspect it's just that some of the particles are so small and fast moving (pumped constantly around the system) that the magnets simply cannot catch them. But I've no idea.

Ideally, with any 'flush', it does end with that - a 'flush'. Ie, system drained down completely after the chemicals and filter have done their thing, refilled, run for a good hour, and drained again.