C Plan CH/HW - Vent?

[parkview094]

Having recently moved house, the pump on the central heating packed up over the weekend, so this prompted me to try and understand our inherited central heating/hot water system better.

It looks to be a C-Plan set up to me, with a pump on the central heating circuit and a separate flow/return from the boiler to the hot water cylinder.

Having turned off the supply to the F&E tank in the loft to allow the system to be drained down to replace the pump, it suddenly struck me that the F&E tank has a snug fitting lid and no obvious vent pipe.

Looking at the hot water cylinder, one connection from the boiler has a T which I assume is to the feed, the other is just straight into the boiler. Does this mean there is no vent on the HW coil? ..is a vent needed? Couldn't the system just vent back through the supply from the F&E tank?

..part of my reason wondering this, is that shortly after moving in, I discovered that the F&E tank ball valve was stuck and the tank split. I got a guy in to replace the tank, but am now wondering if he's just cut off the vent somewhere or if there never was one in the first place. I presume the vent should be into the F&E as opposed to out an overflow or into the cold water cistern?

 

[cross thread]

if the boiler has a overheat thermostat you can use a 22mm single feed this acts as the vent and feed

 

[parkview094]

if the boiler has a overheat thermostat you can use a 22mm single feed this acts as the vent and feed

Aha! The 'T' into the hot water cylinder is definitely 22mm. When you say that can act as both a vent and a feed, does that mean there should still be an open vent, or is the 22mm pipe running into the bottom of the F&E tank sufficient?

Probably a silly question, but how could I tell if the boiler has an overhead thermostat? there's nothing obviously bolted to either the tank or the boiler that would look like a thermostat to me...

 

[twgas]

What boiler, make and model, do you have, one of us is likely to know if it has an overheat 'stat.

 

[parkview094]

It's an Ideal Standard E Type, I believe a RS 60N.
I feel compelled to go and check the cold water cistern now, but does the same principle apply to the CH side of the circuit.. can a combined vent/feed be used?