Routine maintenance for non-sealed hot water CH system? (not including boiler)

[Drake]

Is there anything that should be done at regular intervals to maintain a non-sealed domestic gas-fired central heating system? I'm not concerned about the boiler, as this is checked and maintained by a pro every year. It's the rest of the system I am concerned about: the pipework, the rads, the header tank, etc.

Apert from bleeding the rads occasionally, should other maintenance be doune routinely? Should any kind of chemical be added to the water? Should the sytem be flushed, and how often?

Thank you,

Drake

[TheScullster]

"Drake" wrote

Make sure there is rust inhibitor in sufficient quantity - usually Fernox or Sentinel product. Check state of header tank - that it is covered, insulated and has no fungal growth or debris in. Check that there is no evidence of pump-over back to the header tank (visible or audible signs or tank getting hot) Check that ball float valve works freely and it is set such that the tank does not overflow. Make sure all loft pipes are well lagged

Rads should require next to no bleeding once the system has settled (can take upto a week) after drain/fill.

If you have recently taken on a system, would certainly advise draining with gauze over hose discharge to catch crud. This will give you a good idea of system state. Hopefully minimal crud will appear - then fill, drain to flush, and re-fill adding inhibitor.

Should be good for 3-5 years provided no draining or part draining is carried out.

HTH

Phil

[Dave Liquorice]

That "pro" is British Gas is it? Does it still work after they have finished with it?

The rads should not need routine bleeding. If you have one or more that does need bleeding the you have a problem with the system. Either air getting drawn in some how, a leak or pump over, bringing fresh water (and dissolved air) into the system causing corrosion and the liberation of hydrogen.

It should have an inhibitor to reduce/stop corrosion. Fernox or Sentinel are known brands.

Not routinely. If the system has no inhibitor then a clean and flush might be advisable before refilling and adding inhibitor.

The only regular (annual) stuff I do is close fully, open fully, then close 1/4 to 1/2 a turn the gate valves. If our heating stayed off during the summer I'd fire it up every month or two for an hour or so and also set any TRVs to max. TRVs have a habit of sticking closed if not exercised.

[Drake]

Thank you for the tips. I will do what you said. I don't think the system has been drained for about ten years. Nor has any inhibitor been added in at least that time.

Drake

[Drake]

Yes, because all he does is look at the boiler then try to flog us a new one ...or if it's an consciencious bloke, he tells us the old one is perfectly fine!

What does a 'clean and flush' consist of? Do you mean just drain and refill, or were you meaning some kind of chemical cleaning procedure?

Ah, yes... I had forgotten about the sticking TRV problem. Thanks for reminding me - and for the other tips.

Drake

[Christian McArdle]

Personally, I would:

Drain Refill with fresh water Run entire system for 10 minutes Drain Refill with water and Sentinel X400 Run system for a week, ensuring that all parts get used Drain Refill with water and Sentinel X100.

This will clean out most systems that aren't already showing any major signs of malfunction.

Christian.

[TheScullster]

"Drake" wrote

If your initial draining of the system reveals any quantity of sludge or gritty particles you need to:

Add cleaning agent - again Sentinel or Fernox I did this via towel rail, isolate towel rail and part drain - take out bleed connection and add chemical via funnel. Replace bleed connection, open valves and bleed. This makes sure the stuff is in the system, not in the bottom of the header tank. Wind the temperature up and circulate at speed around all system. (All as instructions on tin and checking boiler and system materials are compatible with chemical used) Drain, refill and circulate again to clean. Drain and refill adding inhibitor.

Phil

[Drake]

Thanks very much for the detailed instructions. That's very helpful.

Drake

[Drake]

Great - thanks.

Drake