Regular Bleeding needed

[dormermike]

Hi

My old CH system has two bleed points (its open vented btw, Y plan) the bleed points are either side of the diverter valve.

I regularly need to bleed small amounts from the manual bleed valves - does this mean there is a leak? I never hear the expansion tank filling up or even dripping - there is about 3 inches of water in the tank (at least). There is inhibitor in the system (added couple of weeks ago).

Thanks

 

[tincup]

Hi


Seems like it might need cleaning out. Sludge and corrosion create gas and means regular venting required.

HTH

 

[bengasman]

There is inhibitor in the system (added couple of weeks ago).

Probably ( more than ) a couple of years too late.
Look in headertank, if it's brown inside, your system is full of crap.

 

[dormermike]

It is just air not gas, not even remotely smelly if that means anything..?

Header water is clear but has crusty white deposits around edges.

Rad water tends to be mostly clear but black at bottom.

Its an old boiler.

Would flush help or be too risky?

 

[dormermike]

Btw its never the rads that need bleeding, always the two bleed pipes near pump and occasionally the bypass rad...

 

[bengasman]

Header water is clear but has crusty white deposits around edges.

My fault, should have specified: bottom of header tank. Even systems that are really badly corroded, usually have clear water.

Its an old boiler.

That's no way to talk about your missus.

 

[dormermike]

Header water is clear but has crusty white deposits around edges.

My fault, should have specified: bottom of header tank. Even systems that are really badly corroded, usually have clear water.

Its an old boiler.

That's no way to talk about your missus.

Ooooh cheeky ! LOL

OK i'll check the bottom of the header tank. There is no lid on it so easy to see. What do you reckon the white crusty stuff is and should I replace the tank?

 

[dormermike]

I think im going to put some cleaner in the system as the history of this system is unknown.

I know putting engine flush in a high mileage car can be disasterous as it can shift carbon deposits.. is the same true of putting a CH cleaner in a old central heating system? System was installed 1994 and not a huge amount of sediment in bottom of rads, but it is there. I have to regularly bleed quite large amounts of air from system.. no signs of any leaks.

 

[heatingeng]

I think im going to put some cleaner in the system as the history of this system is unknown.

I know putting engine flush in a high mileage car can be disasterous as it can shift carbon deposits.. is the same true of putting a CH cleaner in a old central heating system? System was installed 1994 and not a huge amount of sediment in bottom of rads, but it is there. I have to regularly bleed quite large amounts of air from system.. no signs of any leaks.

it can if you do not clean it back out

 

[dormermike]

Just wondering - i tried lighting the "air" that was coming from the bleed points - it doesn't light - is that a sign there could be a leak? Supposing there was a small leak, would it actually cause air to be introduced into the system, or would it just cause the header tank tap to run?

Thanks

 

[heatingeng]

Just wondering - i tried lighting the "air" that was coming from the bleed points - it doesn't light - is that a sign there could be a leak? Supposing there was a small leak, would it actually cause air to be introduced into the system, or would it just cause the header tank tap to run?

Thanks

Could mean a number of things, not piped correctly, pumping over and sucking air in, system corroding etc etc.
http://www.cheapcentralheating.co.uk/how-to-guide-central-heating.html