Sort of flushing a vented heating system

[hellopaul2]

Hello,
I've recently had a load of work done extending my house, including adding underfloor heating and I have some Sentinel X100 to chuck into the vented heating system. I've taken a look at the water in the system (hose on UFH manifold into bucket) and it's slightly grey with some small flecks in it. I can clearly see the bottom of a standard size orange builder's bucket when it's full of the water. The system has been worked on (drained, refilled, not powerflushed) quite a few times over the past year, so the water's all reasonably fresh. So...

Before I go adding the X100, I'd like to flush the system - a bit. I'm assuming that if I open the drain valve so it's draining at a rate slightly slower than the F&E tank is filling, then I'll be able to leave it for an hour or so gently rinsing the system. I know it's nothing like a powerflush or anything, but is there any reason not to do this, just to rinse things out?

I'm then proposing to shut off the mains supply, drain it a bit more, then put the X100 into a towel rad - the F&E tank is a sod to get to. Then open the mains valve to let it top up...then bleed the rads.

Any thoughts, anyone?

- Paul

 

[kbdiy]

If you're going to the trouble of flushing I would think it was worth running some X400 round the system for a couple of weeks. I would also take each rad off and flush through with a hose to get all the crap out. Then do a thorough flush, refill using X100 and bleed.

 

[JohnD]

+1

A plain water drain and rinse does not get much dirt out, If you add X400, you will probably see the water quickly goes inky black with dislodged sediment.

As the weather is warm, and you won't want the heating on much, turn the boiler thermostat down, and the pump speed up. For the first day or so, turn off all radiators except one, and move round all the rads so that each has a time as the open one, so it gets the most circulation you can manage.

After the chemical has loosened the sediment, and you have drained and rinsed it, yes, it is a good idea to hose through them individually in the garden.

BTW bale out all the mud from the F&E tank first, and sponge it clean. No sense in letting all that dirt flow down into the system.

If you can afford £100 for a system filter, it will catch future circulating particles before they can collect into a blockage.

 

[hellopaul2]

John, by "system filter", do you mean one of those magnetic things that apparently catch all the metallic bits?

About a year / 18months ago I put in some X400 for a week or two . It's probably due another flush, but I don't have time to take all the rads off and hose them out. I think I'll probably just live with my rinsing/X100 plan, and maybe do a full flush in the spring. I'd love to clean out any crud in the F&E tank, but it's tucked right into the corner of the loft; cleaning it is something to do on a really cold day, up there with all the insulation!

- Paul