Draining central heating system - UPDATED Q PLEASE

plumb1_2

This type of install was introduced by Yorkshire copper in the late 70's and 80's
It was one of the first type of Micro bore systems using manifolds and 10mm pipe.
They also introduced the dreaded twin entry valves later, using pipe as small as 6mm:eek:

aliasojo

Last quick q please.........the bottle of Fernox cleaner I have says it can be left to circulate in the system for up to a week.

What happens if it's left longer? Would it cause any damage? Or just not be effective after that point?

keystone

Wouldn't leave it in there longer than about 3.

Cheers

aliasojo

3 days or 3 weeks?

happybiker

Op. Drain the system from both the drain cocks and flush a little before you refill and add cleaner. The period cleaner is left in for depends on how much you have the heating running. We used to reckon 2 days running the heating for 3hours a day for a relatively clean system ( no sludge or black iron oxide) and 7 days running the same for a sludged up system. Beware that if there is any sludge in the radiators, it may be blocking pinholes caused by corrosion. Watch the radiators constantly for tiny leaks whilst the cleaner is in circulation.

Flush the cleaner out at least 4times by filling and emptying the system. This will mean allowing water to escape under the floor as all pipework needs to be emptied thoroughly

Very importantly, get a few new drain !!!! washers in stock before you start, they often go hard and break up or split when doing this type of work. Replace them anyway after the final flush, before introducing inhibitor.
Hope that helps

aliasojo

Bump for new question - 1st post.

ValHaller

aliasojo wrote: »

NEW QUESTION:

Forgive me if this is a stupid idea or question, I'm happy to admit there's something I'm not seeing or not understanding......but is there a reason why, instead of draining down the system to get rid off the cleaner and dirty water and then refilling it, I can't just turn on the tap on the filling loop under the boiler and let the water flush through the system continuously, coming out through the open drain valves?

That way, I'd lessen the potential for airblocks and I'd not need to open all the air valves on the rads?

That seems too simple, there must be a reason why I can't do it.

Basic reason is that you require to drain the system as fully as possible to remove the cleaner. If you don't drain down fully and face up to emptying the radiators, the best you can do is progressively dilute the cleaner.

keystone

aliasojo wrote: »

3 days or 3 weeks?

Sorry - thought the UOM was weeks - so three weeks then.

Cheers

aliasojo

keystone wrote: »

Sorry - thought the UOM was weeks - so three weeks then.

Cheers

No idea what UOM means keystone, but thanks for clarifying anyway.

It might seem obvious but if there is any room for ambiguity, I now always check. I'm happy to look like a fool for asking but at least I'll be an educated fool. :rotfl: Iyswim.

keystone

Unit Of Measure - sorry to use acronym speak.