Expansion vessel change on a viessmann 200wv

[macka09]

hi guys. I’m after some advice on replacing a viessmann expansion vessel if anyone has any? I’ve never worked on one or installed one. I don’t normally do part replacements at all if I’m honest so any help would be appreciated please. Cheers

 

[townfanjon]

Straightforward pal , are you sure its knact ?

 

[Chalked]

In all the flat expansion vessels that I have come across. I would say only 10% are gone. Some just lost their pressure, some even from new are flat. Some just need shrader valve replacing.

 

[macka09]

I have no idea chaps. I’m just being sent to replace it. I just can’t seem to see anything in the manual and as I’ve not worked on one I’m just trying to get a heads up really.

 

[EvilDrPorkChop]

They're easy to do. I usually have to take them out to recharge them anyway when they've filled up with water. Valve is on bottom so you can't seem to pump the water out of it.

 

[macka09]

Is it a full drain down then to take these out or can just the boiler be drained?

 

[EvilDrPorkChop]

Is it a full drain down then to take these out or can just the boiler be drained?

Depends if you want to mess with the isolation valves. I usually just drain the system. Be careful as if they're full of water they're pretty heavy too!

 

[macka09]

Depends if you want to mess with the isolation valves. I usually just drain the system. Be careful as if they're full of water they're pretty heavy too!

No don’t fancy risking the isos to be honest. Is it connected with a flexi hose?

 

[townfanjon]

Iso valves on them are pretty good , I would lower pressure from top of heat ex , close vent , pray it pulls a vacuum, stand buy with a wet vac and off yer go . Changed leaking air vent on my 200 a few months since , didnt drain system or fully drain boiler .

 

[townfanjon]

Yes , flexi hose

 

[macka09]

Yes , flexi hose

I don’t wanna risk flooding the place haha

 

[macka09]

Well I got it done folks. Had to drain the system as the isos wouldn’t budge at all. Seems a really complex set up the viessmann 200. May just be me

 

[townfanjon]

Well I got it done folks. Had to drain the system as the isos wouldn’t budge at all. Seems a really complex set up the viessmann 200. May just be me

Loads of room though , bit easier to change than a woooster eh

 

[macka09]

Loads of room though , bit easier to change than a woooster eh

Funny you should say that. I’ve only changed one other and it was a Worcester. You’re right there was loads of room.