Drain C/H system to change secondary heat exchanger on combi?
 

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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Drain C/H system to change secondary heat exchanger on combi?
 

"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

Drain C/H system to change secondary heat exchanger on combi?
 

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.

Drain C/H system to change secondary heat exchanger on combi?
 

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

Drain C/H system to change secondary heat exchanger on combi?
 

"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.

Drain C/H system to change secondary heat exchanger on combi?
 

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.