what type of system do I have?

[Zipadee Doodar]

I need to replace a radiator, and will read all the FAQs, but I do not know what type of system I have - sealed or other.

I have a Vaillant ecomax combi which has a pressure gauge, and lots of whistles, bells and flashing lights. Although there is a header tank in the loft, all pipes to it have been disconnected. Does this mean I have a sealed system?

TIA

[Sparks]

If you don't have a (connected) header tank, and have a pressure gauge, it would be a sealed system.

You should also have a filling loop somewhere, usually near the boiler, where you can increase the pressure of the system.

Sparks...

[Zipadee Doodar]

[Ed Sirett]

(These) Vaillant boilers have internal filling loops operated by screw-head-slotted valves accessed from below and immediately left and right of the return pipe coupling.

See Bottom FAQ. HTH