Inhibitor for a combi

[rick]

Never had a combi, but parents house has a Baxi 100HE

Thinking it would be a good idea to flush, run a system cleaner, then install inhibitor. I have bottles of those for free.

How do you install these into a combi ? ..... the products are just standard plastic bottles.

There is an alternative of an aerosol that I assume can use via filling loop but I would then be paying £15 a bottle.

Is there some trick to getting into the system.

Only option without cracking open boiler would be via a rad .... but air vent hole is tiny and these bottles have large diameter tops.

[John]

Turn off radiator valves - bleed air. Remove a top bung off the radiator. Loosen bottom connection to drain enough water. configure some way - perhaps empty washing up liguid bottle - to squirt inhibitor into radiator. Replace bung, turn on valves, bleed and run the system.

[Max Demian]

When the gas man did mine, he put it in through a valve at the top of a tall towel rail.

[Michael Chare]

I removed the air vent from the top of one of the radiators after partly draining the system. The Fernox I bought came in a bottle with a small plastic pipe that fitted in the hole. A washing up liquid bottle might well be a suitable container for squirting liquid into a radiator.

[John Rumm]

The same as any other sealed system...

(combi is not synonymous with a sealed system. Most (bit not all) combis use a sealed system, but plenty of other non combi boilers also have sealed systems)

You can do it at a rad. Close both valves, then drain a litre of two of water by undoing the union nut on the rad side of the valve. Open the air vent to let some water out. Re-tighten the union nut, and remove the entire bleed screw plug or the blanking plug and pour the does in with a funnel and a short length of hose.

If you have a magnaclean style filter, then they are also an easy place to dose. Isolate with its taps, drain, and refill with inhibitor.

[Cynic]

Rick posted Never had a combi, but parents house has a Baxi

Have,you reason to believe there isn't inhibitor already in the system?

[rick]

Ended up taking out bung from rad ... lucky only one rad had this type of fitting, others are older Stelrad units with welded in air bleed at one end and no bung at other.

Used a funnel with a price of pvc hose .... fiddly but got it done.

At least in searching for 'inject point' I found out it has a magnetic 'filter unit' ... drained that, loads of magnetite crud came out.

Interesting watched British Gas do annual service and he never touched this valve .... and its supposed to be drained annually.

Got system well hot, now off, will leave it soak for 2 weeks then drain, flush and put inhibitor in.

[Tim Lamb]

er.. can't you use the magnetic filter as a fill point? Drain/fill/circulate/drain/fill... until you have got the full amount loaded?

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