Hi, Is is necessary to drain a domestic C/H system just to change
secondary heat exchanger on a combi boiler (Brittony 80)?

Thank you,

Al D
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"Al D" wrote in message
...

Hi, Is is necessary to drain a domestic C/H system just to change
secondary heat exchanger on a combi boiler (Brittony 80)?

Thank you,


Not if you can close off the system isolation valves. Then you only need to
depressurise and drain the boiler

On Thu, 24 Nov 2005 18:37:12 +0000 (UTC), "John"
wrote:


Hi, Is is necessary to drain a domestic C/H system just to change
secondary heat exchanger on a combi boiler (Brittony 80)?

Thank you,


Not if you can close off the system isolation valves. Then you only need to
depressurise and drain the boiler

I can close off the system isolation valves.
How do I depressurise the boiler?

Thanks again,

AL D

= = = = = = = = = = = = = =
to email me, first remove
the three-letter animal from my email address.

On Thu, 24 Nov 2005 20:30:44 +0000, Al D wrote:

On Thu, 24 Nov 2005 18:37:12 +0000 (UTC), "John"
wrote:


Hi, Is is necessary to drain a domestic C/H system just to change
secondary heat exchanger on a combi boiler (Brittony 80)?

Thank you,


Not if you can close off the system isolation valves. Then you only need to
depressurise and drain the boiler

I can close off the system isolation valves.
How do I depressurise the boiler?


Most combis have isolators on the flow and return connections.
Follow the procedure in the manual.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

"Al D" wrote in message
...
On Thu, 24 Nov 2005 18:37:12 +0000 (UTC), "John"
wrote:


Hi, Is is necessary to drain a domestic C/H system just to change
secondary heat exchanger on a combi boiler (Brittony 80)?

Thank you,


Not if you can close off the system isolation valves. Then you only need
to
depressurise and drain the boiler

I can close off the system isolation valves.
How do I depressurise the boiler?

Thanks again,

If you look in the manual it should show the location of the drain point.
Don't use the safety valve as they almost always get a bit of crud under the
seat and will not seal properly again.

On Thu, 24 Nov 2005 21:17:03 +0000 (UTC), "John"
wrote:


If you look in the manual it should show the location of the drain point.
Don't use the safety valve as they almost always get a bit of crud under the
seat and will not seal properly again.

Yes! The manual showed a drain plug under the diverter valve, but when
I looked, all I could see was solid black plastic! So I had to use the
pressure releif valve - and yes, you were right: it dripped
afterwards. I took it to bits and cleaned it but it still dripped! So
I smeared a bit of silicone grease over the mating surfaces. All is
watertight now.

Cheers,

Al D
= = = = = = = = = = = = = =
to email me, first remove
the three-letter animal from my email address.