Hi all,

After cleaning, flushing rads and pipework, installing a new Grundfos
Alpha2 pump, a programmable room stat and more TRV's, I was thinking
of converting to a sealed system from open vented in my 8yr old house
to continue with the modernisation of the system.

The boiler is a GW Micron 50FF, which I have confirmed will be ok with
a pressurised system. I have a couple of queries though and would
appreciate some confirmation or correction. I have read Ed's sealed CH
FAQ.

I was thinking of replacing the feed/expansion tank in the loft with
the expansion vessel, feed loop and pressure valve and discharge,
using the existing pipework there as there is no room in the airing
cupboard for the vessel. Connecting the expansion vessel to the vent
pipe and connecting the mains water feed from the tank to the water
inlet via the filling loop. This will end up with the expansion vessel
being plumbed before the pump. Is this all ok ??

Can I use the overflow pipe from the F/E tank to connect to the
pressure relief valve as a discharge pipe? It's plastic and teminates
outside via the fascia board (two storey house) overlooking our back
garden.

Twelve rads and the boiler, calculating approx 10 litres for each, I
scoped a 18 litre expansion vessle which would give a nice tolerance
over the required capacity.

I also have one of those Aerjec things in place:

http://www.ridgeonsukstoreonline.com...H1600010_m.jpg

I understand this will likely be defunct in a sealed system. Can I
leave this in place or should I take it out and plumb the pipes back
together?

Thanks,

Jon

In article
,
Jon wrote:
After cleaning, flushing rads and pipework, installing a new Grundfos
Alpha2 pump, a programmable room stat and more TRV's, I was thinking
of converting to a sealed system from open vented in my 8yr old house
to continue with the modernisation of the system.

The boiler is a GW Micron 50FF, which I have confirmed will be ok with
a pressurised system. I have a couple of queries though and would
appreciate some confirmation or correction. I have read Ed's sealed CH
FAQ.

I was thinking of replacing the feed/expansion tank in the loft with
the expansion vessel, feed loop and pressure valve and discharge,
using the existing pipework there as there is no room in the airing
cupboard for the vessel. Connecting the expansion vessel to the vent
pipe and connecting the mains water feed from the tank to the water
inlet via the filling loop. This will end up with the expansion vessel
being plumbed before the pump. Is this all ok ??

My opinion is it's not worth it. It might be if you needed the position
taken by the header tank.
When you do come to replace the boiler you might - as I did - decide on a
system one, and that includes the pressure vessel.

--
*To be intoxicated is to feel sophisticated, but not be able to say it.

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 28 Nov 2008 03:41:57 -0800 (PST) someone who may be Jon
wrote this:-

After cleaning, flushing rads and pipework, installing a new Grundfos
Alpha2 pump, a programmable room stat and more TRV's, I was thinking
of converting to a sealed system from open vented in my 8yr old house
to continue with the modernisation of the system.

Is converting a heating system to "unvented" a modernisation?


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

In an earlier contribution to this discussion,
Jon wrote:

Hi all,

After cleaning, flushing rads and pipework, installing a new Grundfos
Alpha2 pump, a programmable room stat and more TRV's, I was thinking
of converting to a sealed system from open vented in my 8yr old house
to continue with the modernisation of the system.


I considered doing something very similar with my system, but decided in the
end to wait until such time as the boiler has to be replaced.

I think what you're suggesting should work, though I'm not sure about the
plastic overflow - the water discharged by the pressure relief valve could
potentially be pretty hot!

One thing which put me off is that, although my boiler (Baxi Solo PF MkI) is
suitable for use in an unvented system, the installation manual says that
the relief valve should be "close to the boiler" - which it certainly
wouldn't be in my case if mounted in the roof space above the airing
cupboard.

Another consideration was the fact that my roof has a fairly low pitch
(about 30 degrees) and the F&E tank is mounted in the eaves with very little
headroom. Although I could probably install the expansion vessel in its
place, I'm not sure that I fancy having to grovel in there at a later date
for maintenance work such as checking/re-charging the air pressure - or even
for operating the filling loop.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On 28 Nov, 13:59, "Roger Mills" wrote:
In an earlier contribution to this discussion,

Jon *wrote:
Hi all,

After cleaning, flushing rads and pipework, installing a new Grundfos
Alpha2 pump, a programmable room stat and more TRV's, I was thinking
of converting to a sealed system from open vented in my 8yr old house
to continue with the modernisation of the system.

I considered doing something very similar with my system, but decided in the
end to wait until such time as the boiler has to be replaced.

I think what you're suggesting should work, though I'm not sure about the
plastic overflow - the water discharged by the pressure relief valve could
potentially be pretty hot!

One thing which put me off is that, although my boiler (Baxi Solo PF MkI) is
suitable for use in an unvented system, the installation manual says that
the relief valve should be "close to the boiler" - which it certainly
wouldn't be in my case if mounted in the roof space above the airing
cupboard.

Another consideration was the fact that my roof has a fairly low pitch
(about 30 degrees) and the F&E tank is mounted in the eaves with very little
headroom. Although I could probably install the expansion vessel in its
place, I'm not sure that I fancy having to grovel in there at a later date
for maintenance work such as checking/re-charging the air pressure - or even
for operating the filling loop.


Thanks for your replies guys. Maybe I'll take your advice and leave it
until the boiler packs up.

On Fri, 28 Nov 2008 03:41:57 -0800, Jon wrote:

Hi all,

After cleaning, flushing rads and pipework, installing a new Grundfos
Alpha2 pump, a programmable room stat and more TRV's, I was thinking of
converting to a sealed system from open vented in my 8yr old house to
continue with the modernisation of the system.

The boiler is a GW Micron 50FF, which I have confirmed will be ok with a
pressurised system. I have a couple of queries though and would
appreciate some confirmation or correction. I have read Ed's sealed CH
FAQ.

I was thinking of replacing the feed/expansion tank in the loft with the
expansion vessel, feed loop and pressure valve and discharge, using the
existing pipework there as there is no room in the airing cupboard for
the vessel. Connecting the expansion vessel to the vent pipe and
connecting the mains water feed from the tank to the water inlet via the
filling loop. This will end up with the expansion vessel being plumbed
before the pump. Is this all ok ??

Can I use the overflow pipe from the F/E tank to connect to the pressure
relief valve as a discharge pipe? It's plastic and teminates outside via
the fascia board (two storey house) overlooking our back garden.

Twelve rads and the boiler, calculating approx 10 litres for each, I
scoped a 18 litre expansion vessle which would give a nice tolerance
over the required capacity.

I also have one of those Aerjec things in place:


I would mount the expansion vessel on the feed pipe in the loft.
I would mount the releif valve near and outside wall (do not use the
plastic pipe for a discharge pipe, it may well never be needed, but it may
one day have to discharge steam).
I would mount the filling loop in the airing cupboard, with a pressure
gauge nearby.
You can leave the Aerjec in situ.
I'd chop back to near the top of the Aerjec and put a manual (or auto)
bleed/vent unit on it.

As others have said if the existing system is not drawing in air or
pumping over there is little to be gained.

--
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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html