Central Heating - Water - Leave well alone ?

[jirams]

Is there any merit in the statement that if there is no evidence of sediment in a central heating system and no leaks, then it is best not to drain it down or flush as part of routine service ?

The argument being that the introduction of fresh water brings in more oxygen which assists corrosion.

I have in mind a system that has not been drained for around 28 years, has a Baxi 552 BBU, has even heat distribution over all rads, is in Scotland in a soft water area. The system comes on full within 30 minutes (indirect DHWS with circ pump for 9 rads). The rads never need bled.

 

[Plumbstar Tom]

if it aint broke dont fix it come to my mind

I have drain down a system filled in back up with inhibitor and had the odd leak that was there before i drain down

Accused to be my fault of course

 

[PlumbBobBob]

i would at least top up the inhibitor if any in system. wouldn't do any harm to change water in system.

i stand corrected (see below)

 

[jirams]

i would at least top up the inhibitor if any in system. wouldn't do any harm to change water in system.

Never had inhibitor in it - what do you see is benefit in changing water given the performance quoted in OP?

 

[gasmarc]

i defo would not touch it unless you want a potential nightmare and trust me they can happen

 

[djboyd]

Hmm, preventative maintenance?

 

[royston]

Yeah do not mess.

 

[GrahamM]

It like the oil seals in an old car.
The old, thicker, dirty oil is working fine until you replace it with new fresh oil that starts to finds its way though the seals and low and behold you have a full engine rebuild on your hands.
Sometimes it is just better to leave alone and top up if need be. As others have said "if it aint broke don't try fix it."