Worth doing a central heating sludge draindown twice?

[dominoman]

My central heating system is old, grumpy and full of old black water and sludge.

I don't dare to do a powerflush as I have enough leaking joints to replace as it is - and I'm pretty sure a powerflush would pop a few more.

Instead I have just fitted a Fernox TF1 (easy enough) and am going to put some Sentinel X400 sludge remover in and leave it a couple of weeks.

When I bought the Fernox TF1 I also got an extra bottle of sludge remover (plumbing merchant's home brand one), so my question is should I do the whole thing twice. i.e. Fill the system, leave a couple of weeks, drain down then repeat with another bottle of sludge remover.

Is it likely to do much more the second time around?

 

[footprints]

I don't see it can do any harm so long as both chemical flushes are thorough.
Just a question of how much patience you have, flushing well is tedious, I bet by the time you have done the first one you will decide to "leave it for a while"

 

[dominoman]

I don't see it can do any harm so long as both chemical flushes are thorough.
Just a question of how much patience you have, flushing well is tedious, I bet by the time you have done the first one you will decide to "leave it for a while"

I've not done a flush before. How should I do it "well"?

I was planning to just add the sludge remover stuff to the feeder tank, refill the system, bleed radiators, and then leave it to run as normal for a couple of weeks.

Is there something else I should do to make it more effective?

 

[footprints]

Yes drain a fair part of the system that will make sure the stuff doesn't just sit in the header tank, put in the chemical then refill fully refill and run for the specified time, then drain while the system is warm.

I tend to leave the header tank on for a while still refilling the system as the chemical drains out, then turn off, drain completely and open air bleeds what happens however is that a lot of pipework under the ground floor in particular (which often has a fair bit of sludge) holds water.

So TURN OFF THE AIR BLEEDS and restore the water to the tank then let it run clear at the hose.

If you haven't lost the will to live you can fill, drain and refill one more time adding the new inhibitor or in your case sludge remover.

The best thing to do once you have the system as clean as possible is remove each rad and flush out on the garden with a hose, surprising how much is left but that is a horrible job and a REALLY good way to ruin your carpets

 

[JohnD]

Bale out all the mud from your F&E before you start, and sponge it clean. No sense in washing extra dirt into the system.

After you have done the flushing, and it is back in service, keep emptying your filter, and over a period of months you will see the residual sludge diminishing.

Sentinel X900 can be added to the X100 inhibitor on your final fill. X900 is fairly new, and is supposed to loosen sediment so the filter can trap it. It is not drained out, but left in circulation permanently.

BTW if you ever take radiators off to hose through, turn them upside down as soon as you take them off the wall, to prevent sludge dribbling out.

 

[ALCPlumbing]

Bale out all the mud from your F&E before you start, and sponge it clean. No sense in washing extra dirt into the system.

After you have done the flushing, and it is back in service, keep emptying your filter, and over a period of months you will see the residual sludge diminishing.

Sentinel X900 can be added to the X100 inhibitor on your final fill. X900 is fairly new, and is supposed to loosen sediment so the filter can trap it. It is not drained out, but left in circulation permanently.

BTW if you ever take radiators off to hose through, turn them upside down as soon as you take them off the wall, to prevent sludge dribbling out.

With the bleed screw tightened.