Is this good or bad practice. Should I install isolation valves on the ch
flow and return and the dhw in/out, about 6 inches under the boiler
connections (obviously making allowances for the filling loop and it's
connectors, etc).

Haven't really thought through the benefits of this, or the cons
(un-nessecary restrisctions right at the start of the runs, maybe), but just
thought I'd check with the group.

I'm guessing that there's no real need?

Jon

In article ,
"jon" writes:
Is this good or bad practice. Should I install isolation valves on the ch
flow and return and the dhw in/out, about 6 inches under the boiler
connections (obviously making allowances for the filling loop and it's
connectors, etc).

Haven't really thought through the benefits of this, or the cons
(un-nessecary restrisctions right at the start of the runs, maybe), but just
thought I'd check with the group.

I'm guessing that there's no real need?

If you buy a fixing jig for a boiler, I think most
include all the isolation valves on the jig. If you
add them separately, make sure you use full-bore valves.
I found them useful whilst installing the system, and
when trying to isolate the location of a leak (which
turned out to be inside the boiler, and contrary to my
initial suspicions, not in any of my plumbing;-).

--
Andrew Gabriel

"jon" wrote in message
...

Is this good or bad practice. Should I install isolation valves on the ch
flow and return and the dhw in/out, about 6 inches under the boiler
connections (obviously making allowances for the filling loop and it's
connectors, etc).

Haven't really thought through the benefits of this, or the cons
(un-nessecary restrisctions right at the start of the runs, maybe), but
just
thought I'd check with the group.

I'm guessing that there's no real need?

Isolation valves should already be on the boiler. If you are inserting a
strainer on the boiler return, the fit a "full bore" isolation valve either
side so you don't need to drain down to clear the strainer. After
commissioning clear the strainer one a week for two weeks , then once a
month for a few months. By then the loose debris from the old system should
have been picked up by the strainer. This crap which would have entered the
boilers heat exchanger. Also have a strainer on the cold water main supply
to the combi. Debris from the mains can enter too.

"Andrew Gabriel" wrote in message
.. .
In article ,
"jon" writes:
Is this good or bad practice. Should I install isolation valves on the ch
flow and return and the dhw in/out, about 6 inches under the boiler
connections (obviously making allowances for the filling loop and it's
connectors, etc).

Haven't really thought through the benefits of this, or the cons
(un-nessecary restrisctions right at the start of the runs, maybe), but
just
thought I'd check with the group.

I'm guessing that there's no real need?

If you buy a fixing jig for a boiler, I think most
include all the isolation valves on the jig. If you
add them separately, make sure you use full-bore valves.
I found them useful whilst installing the system, and
when trying to isolate the location of a leak (which
turned out to be inside the boiler, and contrary to my
initial suspicions, not in any of my plumbing;-).

Apologies, just had a gander a the fixing plate/jig and there are indeed iso
valves on all in/outlets except for the DHW out.

Jon

On Thu, 16 Jun 2005 18:23:03 +0000, jon wrote:


"Andrew Gabriel" wrote in message
.. .
In article ,
"jon" writes:
Is this good or bad practice. Should I install isolation valves on the ch
flow and return and the dhw in/out, about 6 inches under the boiler
connections (obviously making allowances for the filling loop and it's
connectors, etc).

Haven't really thought through the benefits of this, or the cons
(un-nessecary restrisctions right at the start of the runs, maybe), but
just
thought I'd check with the group.

I'm guessing that there's no real need?

If you buy a fixing jig for a boiler, I think most
include all the isolation valves on the jig. If you
add them separately, make sure you use full-bore valves.
I found them useful whilst installing the system, and
when trying to isolate the location of a leak (which
turned out to be inside the boiler, and contrary to my
initial suspicions, not in any of my plumbing;-).

Apologies, just had a gander a the fixing plate/jig and there are indeed iso
valves on all in/outlets except for the DHW out.

Note that whilst isolation valves are common on combi boilers those units
also have the Pressure Relief Valve inside.

If using a plain heating boiler the PRV must go on the boiler side of any
isolators.

--
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