How to check if boilermate 2000 is full.

[xraynorm]

Hello.

I have a Boilermate 2000 with a glow-worm micron 40ff. I’m pretty sure the boiler is faulty, and I am getting a plumber to have a look at it. However, I want to make sure the boilermate is definitely full before I get the plumber out. Maybe a partially empty boilermate (because of blocked cold feed) could be causing the boiler to overheat and cut out?.

If I connect a hose the mains and fill the boilermate from the open vent until it is overflowing can I assume the boilermate is full?

If there is a better way of doing this could someone tell me.

Any help would be appreciated.

[scorp]

I'm not sure about draining full heating system but if you drained only the Boilermate main tank then it is enough to fill small expansion tank until it stops accepting water. Then just in case turn on heating for 10 mins or so. But in general you don't need to worry because if your expansion tank is in working order then it should be filled automatically.
But if you want to check if it is full before changing boiler then drain a little bit from the main tank and see if water level in small tank decreased, but make sure you blocked main water feed first.