Topping up radiators on Heatslave 20/25 system?

[Antiriad2097]

My daughter has just moved into a house with an old Heatslave 20/25 combi boiler.

She tried bleeding radiators as they're not heating evenly, but she's getting nothing out of them. I'm assuming they need topping up.

On my own system, there's a connection for mains water to top up.

I downloaded the install manual for the Heatslave, but I can't pinpoint where on this one the top up is located. Can anyone point me in the right direction?

I can see the pressure valve on the front and the regular cold water inlet for taps appears to come in from the rear, but I can't pinpoint the rad top up.

Reading the faqs mentions closed and vented systems. What's the difference and how canI tell which I have?

 

[Burnerman]

Being a combi, yours is a closed system that is kept under pressure - typically one bar.
The filling loop can be anywhere really - it injects mains pressure cold water into the central heating return pipe. Generally its near the boiler so you can see the pressure rising, of course. Try inside cupboards, under sinks etc.
John

 

[jackthom]

There's a large front panel which should swing or lift off to reveal the pressure gauge and it looks like there's plenty of room inside the top of the case to hide the filling loop on this one.