Do all indirect cyliders need a bleed valve?

[Vladimir]

Hi all,

As the title says "Do all indirect cyliders need a bleed valve"

I think it's called a "bleed valve" - it's usually beside the cylinder on a little bit of 1/2 pipe to bleed the cylinder coil the way you can bleed a radiator?

Reason for asking is that I am working on a house and there is none.

By the way what is the technical name for this?

Any comments?

V

 

[chrishutt]

Bleed valve is probably correctly called a manual air vent (MAV). It is only necessary if there no other way for air in the top of the cylinder coil heat exchanger (the thing inside the cylinder next to the connection with the MAV) to escape when the system is filled.

 

[Vladimir]

Thanks for reply Chris

The valve I was talking about has a little nut on it that a radiator key would fit. It doesn't have a cap on the top that can be turned by hand.

How do you decide if the cylinder coil needs one of these or not? How else would you "bleed" the coil of air if one of these was not present?

Many Thanks

V

 

[chrishutt]

If the pipework rises (or runs horizontally) up to the system vent pipe then it will vent itself. Otherwise you will need some sort of mechanical device, which can be automatic (AAV) or manual (MAV) - these may have caps or plugs with screws slots or square shanks or whatever.