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I put central heating cleaner in my system recently, now struggling to get it out so I can refill with inhibitor!
It's a combi boiler sealed loop in a bungalow, so all rads are roughly the same height except for the towel rail in the bathroom which is taller.
Drain is on the kitchen rad closest to the boiler, that started draining and I completely removed the bleed screw from the bathroom towel rail and then the kitchen rad. The hose outside is probably 50cm below the drain cock so plenty of fall. All the lockshield valves are open and the thermostatics on max (I removed one but didn't change anything). The rads all get hot and all the thermostatics work.
Every other bleed screw still spurts water, I've now drained about 6 litres from another rad into a pop bottle and now all the bleed screws just dribble water down the side of the rad, so there doesn't seem to be any extra pressure.
However I think all the rads are still full 🙄. Any ideas? Do I start the boiler up for a minute and see if it will pump briefly? The previous owner was a bit of a diyer so if he did the rads himself, could anything prevent it draining to this extent? Does the drain need to be on the flow or return?
My next idea is to get the wet vac on the end of the hose but I don't know if this will damage or collapse the bladder in the pressure vessel thing in the boiler!
Oh and the filling loop is removed and then I turned the water off for good measure and this was before draining the 6 litres. When the first rad drained I could hear water draining through the boiler.
Hosepipe not blocked and if I lay my head on the floor and blow into the drain it doesn't seem to be blocked, splutters back. Everything I've seen so far is pretty clean so I doubt there is enough crap in there to have blocked it
Way too complicated an approach. You don't need to drain down just to fill with inhibitor
Isolate a suitable rad, ideally on a vinyl floor, by closing the valves at both ends. TRVs need the thermo-bit removing and replacing with a cap to close the valve. Some of the tubular headers on vertical rads are a PITA, use a conventional panel rad for access
Release the pressure at the bleed screw, catch tank at the ready.
LOOSEN the valve to rad tail nut and GENTLY control the resulting flow into a catch tank and lots of cloths. Wet vac the gentle flow will be cleaner, although quantity is more difficult to judge. Take double the quantity out of inhibitor to go in
Tighten the rad tail nut, remove the whole bleed screw fitting and fill. Run the process backwards, starting with closing the bleed screw to re-commission
Are you draining simply to remove the cleaner and dirty water? Can you flush it through by using the fill line and drain (keeping the pressure low, obvs!)
If you do use a wet vac, you won't generate enough suction to damage the diaphragm in the pressure vessel.
Sorry, misread. I thought you meant cleaner as in a magnetic filter.
You could still drain per radiator as described
Depending on how the pipework is arranged, you can have loops that go over doors etc. and may have more than one low point. We've got two drains in our house, one in the kitchen and one in the hall.
I suspect all the rads are on ‘drops’ from the ceiling, therefore each one will need to be drained individually.
Well I tried flushing via the filling loop and it just seemed to be flushing clean water out rather than purging the system. I turned it off and opened a few bleed screws but after a few minutes they started leaking again.
I suspect all the rads are on ‘drops’ from the ceiling, therefore each one will need to be drained individually.
They are fed from under the suspended floor but you've just reminded me of something. The kitchen rad is fed from pipes that go down from the boiler under the floor. The rest of the house has pipes that go up from the boiler into the loft, over the kitchen, back down through the cupboard outside the kitchen, and then head off to the other seven rads.
So I suppose I need to add a drain cock to the hallway rad as that's nearest a door 🙄 FFS!
I'd forgotten this little detail. Replacing the kitchen floor soon so I might look into removing that overhead loop as it's the only plumbing in the loft.
Isolate a rad, drain and remove it, adapt a hose onto the end of the valve on the pipe and drain like that. Pick the smallest rad as easiest to remove usually.