How do i isolate my boiler?

[pippalarge]

Hi - first of all i should point out i'm a plumbing novice!

I need to change the temp sensor in my Ferroli Sigma 60-100. It's a wet sensor so i'm informed i need to isolate and drain the boiler first - can anyone tell me how to do this or should i call in the experts?

It's a gravity fed system (non-sealed).

Also how do i then refill / restart the boiler - any particular steps to take?

Any help / advice would be much appreciated - thanks!

 

[Iddy]

Hi,
With it being an open vent system there won't be any isolation valves on the boiler's flow and return connection.

You therefore have the following options:-

1.Turn off the feed FROM the f+e tank (feed and expansion - the smaller of the two storage tanks which would normally be located in the attic) and drain down the system. There would normally be a gate valve (with a wheel head) fitted on a 15mm pipe in the airing cupboard to do this.

2. Or turn off the mains feed TO the f+e tank and drain system down.

3. Another option is to buy a pair of rubber bungs from a plumbers merchants. You would use these to bung both the feed from inside the the f+e tank and the end of the vent pipe that loops, like an upside down U, over the top of the tank. You could then drain down, now though only a little water will come out, the rest will be held in the system.

There should be a drain off valve under the boiler next to th gas connection.[/u][/b]

 

[pippalarge]

Thanks for the info - much appreciated!

I think i'll probably try the bungs method - there are two pipes with wheel valves in the airing cupboard and i don't want to turn off the wrong one.

I remember being advised to do something similar when we had a leaking radiator pipe -in the circumstances I had to improvise by using a carrot but it worked! I'll buy some bungs this time.

This may be a stupid question but how do i then refill the system? I assume it's more complicated than just removing the bungs from the expansion tank? Do i need to do anything to make sure the boiler has water in it etc?

 

[Iddy]

Just remove the bungs! -as simple as that.
Close the drain off valve first of course... sorry - that's obvious.

I always remove the bung in the tank first, then the one on the vent, so that water gets drawn in not air down the vent pipe.

Hope all goes well!

 

[pippalarge]

Thanks again - fingers crossed!