Adding Fernox to CH system

[Thomarse]

Hi,

A few weeks back I completely drained my CH system to move a radiator and do some other pipe works.

I have since filled the system back up with water, but I didnt add the fernox in straight away as i wanted to check for leaks etc and not waste it if I needed to re-drain it.

It's been a few weeks now so I really need to get fernox back in the system, but how?

If I block the water supply to the header tank and drain a tanks worth of water from the system, then add the fernox and allow the tank to re- fill, wont the fernox just stay in the tank, and not get into the system itself?

I really dont want to cause any airlocks doing this as getting them out the first time was a task and a half!

Im sure there is a simple answer out there, so any help would be good!

Tom

[Jim Alexander]

Indeed there is. Just rearrange the steps. (1) block the water supply, (2) add Fernox (3) drain a tanks worth of water from the system.

Jim A

[Stuart B]

Bit late now but fitting a filling point in to the piping near the boiler while the system was drained down would have been better .

Stuart

[Stuart Noble]

You can get a gel concentrate to add to an upstairs rad with a skeleton gun. I just used the bleed valve to drain off the water. Boiler pressure was all over the place for a couple of hours but settled down, and has been fine since.

[John Rumm]

1) Tip inhibitor into feed and expansion tank 2) There is no 2!

You will note that during normal operation water expands into the F&E tank, and then is drawn out as the system cools - hence this will draw inhibitor into circulation in relatively few heating and cooling cycles.

[Andy Hall]

A couple of ways.

- Drain down a header tank's worth and add the inhibitor. Warm up the system (including radiators) and let it cool two or three times. The water expansion and contraction will tend to mix the inhibitor in.

- Better. Buy some gel version and inject at a radiator.

[TheScullster]

"Thomarse" wrote

Do you have a ladder towel rail? If so turn off both valves. Remove bleed or blank fitting from top of vertical leg. Syphon out some water. Introduce Fernox with funnel. Re-fit bleed/blank plug. Turn on both rad valves and bleed any air out of towel rail. This guarantees all inhibitor is introduced to the working system water.

Phil

[Stuart B]

Going by memory when I bought some from Screwfix is the gel not considerably more expensive than the liquid .

When my CH boiler was replaced the fitter just took of a tee from one of the boiler pipes and put a right angled short piece of pipe in and fitted a stop end to it which can be removed to top up or refill with treatment either with care or using a funnel..

Stuart

[John]

We put up with quite a poor spec on systems generally. All should have an external drain pipe with an internal drain c*ck. All should have a decent in-line strainer and a port to inject additives.

Agree?

[Stuart B]

The guy who fitted mine connected up a tap tp drain the system to an outside waste pipe as well as fitting the filler facility ..