Adding inhibitor to sealed central heating system with combi boiler

[aitchpp]

Hi, I live in a one bed flat and have a sealed central heating system with 4 rads and a Vaillant Ecotec combi boiler. To enable decorating, I have taken two radiators off my walls after completely draining the system. I have also changed an old lockshield valve to one that includes a drain (had to drain straight from one of the rads this time). I know I have to add inhibitor when i re-fill the system and have bought 1 litre of Sentinel (not concentrate) and a Screwfix filling kit, but I am still unsure of how best/easiest to go about inserting the inhibitor. I don't know the exact make of my rads but I think they could be Stelrad as they also have slatted tops and sides held on with plastic clips that don't seem to allow easy removal of the sides even though they are supposed to (?). Some google searches have turned up advice to take out both the bleed valve housing and the blank plug from the top of one of the rads and pour it in but I don't think I can get a wrench around the large nuts without taking the sides off which looks very difficult. Also there is a right angle turn into the top of the rad straight after the hole. Another option I found is to turn the radiator upside down and fill from the bottom valve entry point, put the valve back, keep both closed when I turn it the right way up and somehow lift the rad onto its brackets while also ensuring the pipes go into the undersides of the valves first go ! Filling this way would be easier but not putting the rad back. I suppose this is feasible if I get someone to help me but is it a sensible thing to do ? Any better suggestions ? Anyone have experience of the Screwfix filling kit and how to use it please ? Also is 1 litre too much, some google search answers have suggested 1/2 litre for a flat like mine (no harm keeping the other half for top ups in future).

 

[ecowarm]

Hi and welcome to the forum, if the system is still drained remove a rad keeping the valves attached and pour in to open valve. turn off valves, refit rad, open valves and refill system with filling loop.

 

[Simon F]

the screw fix kits are ok, but as its plastic you have to be gentle with it. I had one until the lad i was working with managed to break it.since then i made one to my own design with some pipe and fittings ,just right.
the radiator sides should just pull of, may seem a bit tight, but they are removable.
take the sides off and use the kit you bought.

 

[aitchpp]

thanks, and take both plugs off the top of the rad or is one side sufficient as there is no pressure or water in the system ? and do I need ptfe on the plug(s) when I put it back ?

 

[aitchpp]

thanks, sounds like I should flip a coin between your recommendation and Simon F's

 

[Simon F]

as the systems empty do whatever seems easiest.
it will be easier to put the inhibitor in if another valve is open to let the air be displaced by the inhibitor.
if its one of the newer type bleed valves with a rubber seal, you shouldn't need to use ptfe. if the rubber has become brittle you could use ptfe then or get a new rubber O ring

 

[aitchpp]

thanks Simon

 

[ecowarm]

I agree with simon

 

[aitchpp]

thanks, I'll at least give pulling the sides off a go first, plonking the rad down onto the pipes does concern me a little

 

[S500EED]

when i fill my system with inhibitor i use my
hydrometer to fill the rads, works brilliantly no
mess. they come in handy in all aspects of jobz.

 

[aitchpp]

thanks,
I'm pleased to inform all three of you for future reference that I managed to loosen the blank plug from the top of the radiator without taking the side off, I just about managed to get a grip with an adjustable wrench. I must admit with hindsight I should have protected the casing in case I scratched the enamel paint but I got away with it, I'll protect it when I put it back. I haven't actually put the inhibitor in yet but using just the bottle attachment and short tube from the Screwfix filling kit seems like it should do the job. Thanks again all

 

[FD Powerflow]

With the greatest of respect the easiest way with a Vaillant Ecotec is to isolate the filling loop, unscrew and attached a can of F1 Express on the end, and pull the trigger. No need to drain down, remove bleed plugs or even get wet.

FERNOX F1 EXPRESS CENTRAL HEATING PROTECTOR 265ML

 

[aitchpp]

thanks for that - I had to drain the system anyway because I wanted to change one of the lockshield valves - also I am reluctant (nervous) to touch anything close to the boiler, which part of the loop would I actually have needed to detach, before the valve going into the boiler pipe or detach the whole valve from the boiler pipe ? and if you can feed the inhibitor into the boiler pipe like that, why has no one suggested inserting it into the open end of the radiator pipe before I fitted the new lockshield valve ?

 

[AWheating]

Chemical Dosing Equipment, Chemical Dosing System, Chemical Dosing, Dosing Equipment

i got one of these a few years ago, it comes in very handy if you want to add inhibitor to a full system. it works via filling loop, connect up and turn on filling loop and it pushes the inhibitor into the system.

 

[aitchpp]

superb ! thanks so much

 

[S500EED]

i will try it, but will wait until summer, thats when
the system gets drained out.

 

[gornsgorns]

All i do is take off the bleed valve and put on a little contraption i made! A 1/2" male to 15mm compression elbow with some 15mm pipe going into a bit of 22mm pipe. Then just pour the inhibitor down the pipe. Then put the bleed valve back in and fill up. Works a treat each time.

 

[PlumbBobBob]

i have much the same with the addition of the top of a 2 litre pop bottle to act as a funnel taped securely on

 

[aitchpp]

The screwfix kit sort of works, I just attached the small length of pipe included onto the top of the inhibitor bottle using the adaptor provided and held the pipe in the bleed valve opening. A little spilled out but as long as you stick some plastic carrier bags (or equivalent) on the side of the rad to deflect the leak with some rags on the floor, it's not too bad.