Gravity central heating?
Vic and June
what about the return can it run flat on the floor??
Clogdancer on a fat boat. Abandoned the north to explore the other half before
it sinks.
Julian Tether
<vhyd...@aol.com-no-spam> writes
>The 22mm flow pipe from the boiler should slant up 2inch for every meter but
>what about the return can it run flat on the floor??
There is only really one way to do gravity heating that works and that
is as follows.
Take the exit pipe (hot out) from the boiler straight up to the highest
point that you can (normally under the gunwale). Then slope the pipe
down towards the far end of the system, the pipe should then return to
the cold return to the boiler sloping down all the way.
It is very important that there is a gradual slope over the whole
system.
If using radiators they will be fitted between the out and return pipes
and you must use a minimum of 28mm copper pipe for the loop.
A better way which distributes the heat better over the whole boat is to
use 43mm pipe in the same configuration but no radiators.
Hope this is of help.
--
Julian Tether
Barge Parglena
e-mail: jul...@parglena.co.uk
Captain Beeky
> A better way which distributes the heat better over the whole boat is to
> use 43mm pipe in the same configuration but no radiators.
> Hope this is of help.
Ermmm . . . that'd be 42 or 54 ! Unless the Chinese are making bigger
inroads than I thought.
Beeky of the tube emporium
Julian Tether
<chug...@onetel.net.uk> writes
>Ermmm . . . that'd be 42 or 54 ! Unless the Chinese are making bigger
>inroads than I thought.
I couldn't remember the exact size I knew it was 40 something.....
Neil Arlidge
.......are you still doing Heritage Trips trips round this last outpost of
British Manufactory? ;-)
--
Neil Arlidge - NB Earnest
Follow the travels of the TNC at http://www.tuesdaynightclub.co.uk
Captain Beeky
> .......are you still doing Heritage Trips trips round this last outpost of
> British Manufactory? ;-)
Yerse . . . trying to fit in Brian D on a late Tuesday pm so we can do a
couple of Black Country pubs in the evening. Could make it a Bilston
Tube-o-GiG if anybody's interested.
Beeky
Chris N Deuchar
says...
> In message <20021014145308...@mb-ft.aol.com>, Vic and June
> <vhyd...@aol.com-no-spam> writes
> >The 22mm flow pipe from the boiler should slant up 2inch for every meter but
> >what about the return can it run flat on the floor??
> is as follows.
> Take the exit pipe (hot out) from the boiler straight up to the highest
> point that you can (normally under the gunwale). Then slope the pipe
> down towards the far end of the system, the pipe should then return to
> the cold return to the boiler sloping down all the way.
We have 34ft run (+ return) in one direction and 12ft in the other
tee-d off the back of a torgem in our butty. This rises at approx 1/4"
in 1ft, with a similar fall from the other end, and works fine. On the
motor boat the run is for 30ft with approx 1/2" rise.
All in 22m piping!
> It is very important that there is a gradual slope over the whole
> system.
Agreed - if only to ensure there are no air locks!
> If using radiators they will be fitted between the out and return pipes
> and you must use a minimum of 28mm copper pipe for the loop.
Or just pipe the feed straight through them.
Finally, ensure the expansion tank is at the highest point. This makes
evrything 'self-bleeding'
HTH
Chris D
--
ch...@deuchars.co.uk http://www.Deuchars.co.uk
Author & Publisher: "A Boaters Guide to BOATING" 4-50GBP
Mixing old and new waterway techniques. ISBN 0953151204
Details at: http://www.canals.com/books.htm
Robert Laws
> In message <20021014145308...@mb-ft.aol.com>, Vic and June
> <vhyd...@aol.com-no-spam> writes
> >The 22mm flow pipe from the boiler should slant up 2inch for every meter but
> >what about the return can it run flat on the floor??
> Best not to use 22mm pipe its to small!
My boat (58' long) uses 22mm pipe for the gravity circulated CH system
and it works fine. Heat comes from a Kabola diesel boiler and drives
three radiators.
I agree that, ideally, you want the pipe to run vertically from the
boiler to the maximum height of the upper pipe. This vertical section
should be lagged becuase it's the higher temperature in here that
drives the circulation. The boiler should be a low as possible. In
my case, the upper pipe runs along under the gunwale and the lower one
runs along just above the floor with the radiators linking the two.
Robert
Vic and June
>>> is to use 43mm pipe in the same configuration but no radiators.
>
The makers of one stove say that any bigger pipe than 22mm will be too much of
a thermal shock for gravity feed to work ??
Julian Tether
<ch...@deuchars.co.uk> writes
>
>We have 34ft run (+ return) in one direction and 12ft in the other
>tee-d off the back of a torgem in our butty. This rises at approx 1/4"
>in 1ft, with a similar fall from the other end, and works fine. On the
>motor boat the run is for 30ft with approx 1/2" rise.
>All in 22m piping!
idea of going straight up immediately after leaving the stove because as
soon as it leaves the stove it is cooling.
Graham Keens
Do we have to wear GREY?
Graham
http:/www.jannock.org.uk
Ian McCarthy
The art for gravity flow systems is that hot water rises in proportion
to its temperature, and cross section of the pipe. So to get a flow you
need more hot water rising and cold water falling than the friction of
the system. So on a narrowboat, the bigger the riser from the boiler the
better. Firms like Brown & Tawse (sp?) sell large diameter copper pipe,
min of 42 mm is good but bigger is better. Always slope the pipe to
ensure that all the air will always escape, you do not want an air
pocket partially blocking a pipe. Also don't forget you need the
radiators as low as you can get them, so that you don't get cold feet.
You can use 22 mm, you just get a slow flow rate, you do need a good
force to push horizontally, and then down to a radiator, which implies a
lower total heat output, if you use smaller diameters. If you have a
well insulated boat or you don't want to be to warm when its freezing
outside then that's ok. The other thing is your boiler may well last
longer. You need to ensure that the return water temperature is well
above 30 Degrees C and that the differential is less than 25 D C. This
is because cold water hitting hot water causes oxygen bubbles to appear
and they rot iron boilers for fun. I believe the second rule is more
important than the first so this says a good flow may have advantages,
along as you don't have too many radiators.
There is a lovely bungalow near us which has a solid fuel boiler, and a
gravity central heating system, and the house is always nice and warm,
the riser from the boiler is 4&1/2" iron pipe, the return is 1", There
are no values used to control the flow rates to the radiators its all
done by having the correct size pipes. A real expert installed that
system. Undoubtedly when the old fella dies some one will come along and
install gas, and be cold during the not infrequent the power cuts.
--
Cheers Ian Mac