Got a CH/HW system that is donkeys years old. Works OK, but the
insulation around the water tank has always been crap - totally
shredded red fiberglass+plastic jacket thing. So I pulled the jacket
off to try to gain access to put some half-way effective insulation
onto it. That's work in progress, but when I was removing the old
jacket, a "bulb" from a thermostatic valve came twanging off the
cylinder, and I'm not at all sure where to reposition it while I'm
putting on the next section of insulation.
The bulb connects to a thermostat valve, and I guess that when the
valve closes, hot water from the back boiler is deflected up a pipe and
back into an open header tank, past a bi-metal electrical thermostat,
that I guess turns off the gas.
Question is, should I re-attach the thermostat bulb at the top of the
heated tank, or at the bottom, or at the mid-height of the
heat-exchanger coil?

(My guess is, about half-way up the coil. But I could half-convince
myself that it should be right at the bottom of the tank.)

--
Aidan
Aberdeen, Scotland
Written at Sat, 23 Dec 2006 00:57 GMT, but posted later.

"Aidan Karley" wrote:
Got a CH/HW system that is donkeys years old. Works OK, but the
insulation around the water tank has always been crap - totally
shredded red fiberglass+plastic jacket thing. So I pulled the jacket
off to try to gain access to put some half-way effective insulation
onto it. That's work in progress, but when I was removing the old
jacket, a "bulb" from a thermostatic valve came twanging off the
cylinder, and I'm not at all sure where to reposition it while I'm
putting on the next section of insulation.
The bulb connects to a thermostat valve, and I guess that when the
valve closes, hot water from the back boiler is deflected up a pipe and
back into an open header tank, past a bi-metal electrical thermostat,
that I guess turns off the gas.
Question is, should I re-attach the thermostat bulb at the top of the
heated tank, or at the bottom, or at the mid-height of the
heat-exchanger coil?

(My guess is, about half-way up the coil. But I could half-convince
myself that it should be right at the bottom of the tank.)

Roughly one-third to half way up the cylinder should be fine:
http://www.wrexham.gov.uk/images/hou...h_cylinder.jpg

In article valid,
Aidan Karley lid
wrote:
(My guess is, about half-way up the coil. But I could half-convince
myself that it should be right at the bottom of the tank.)

Convention has it one third of the way up. Or perhaps that should be
convection.

--
*If you can read this, thank a teecher

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

If you want get fancy then get second thermostat - bit of fiddly wiring
etc - but then you could place one 1/3 from the top - and used during
the day - set at a temp when you only need a little h/w for hand
washing etc and the other nearer the bottom which you can use when
baths etc are needed

Would require some extra time clock contacts etc - but worth a thought

In the days of green house gases this could save tones of CO2

"Aidan Karley" lid wrote in
message r.invalid...

Question is, should I re-attach the thermostat bulb at the top of the
heated tank, or at the bottom, or at the mid-height of the
heat-exchanger coil?

(My guess is, about half-way up the coil. But I could half-convince
myself that it should be right at the bottom of the tank.)


The bottom of the tank cools quicker because that is where the cold water
enters, so siting the thermostat bulb low down near the bottom would make it
just that much more sensitive to temperature drops cause by hot water usage.


--

Michael Chare

Caustic, Dave and Michael,
Unanimity ? In uk.d.i.y ?? I'm shocked. And I'm scared that
you're in agreement with me too.
Scary.

Thanks. Half-way up the coil/ 1/3 way up the tank. The thing is
100mm long, so it's not going to be too precise.

--
Aidan
Aberdeen, Scotland
Written at Sun, 24 Dec 2006 01:58 GMT, but posted later.

In article ,
Aidan Karley wrote:
Caustic, Dave and Michael,
Unanimity ? In uk.d.i.y ?? I'm shocked. And I'm scared that
you're in agreement with me too.
Scary.

It's on the instructions you get with a new one.

Of course dribble didn't reply. His answer would have been to replace it
with twin combis. ;-)

--
*Gravity is a myth, the earth sucks *

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

In article , Dave Plowman (News) wrote:
Unanimity ? In uk.d.i.y ?? I'm shocked. And I'm scared that
you're in agreement with me too.
Scary.

It's on the instructions you get with a new one.

No need for a new one as yet, and since the original is going to
be an absolute ******* to get at without removing the tank, it's not
going to get replaced without damned good reason. All I'm doing at the
moment is re-insulating the tank.

--
Aidan
Aberdeen, Scotland
Written at Mon, 25 Dec 2006 10:18 GMT, but posted later.

In article ,
Aidan Karley wrote:
In article , Dave Plowman (News) wrote:
Unanimity ? In uk.d.i.y ?? I'm shocked. And I'm scared that
you're in agreement with me too.
Scary.

It's on the instructions you get with a new one.

No need for a new one as yet, and since the original is going to
be an absolute ******* to get at without removing the tank, it's not
going to get replaced without damned good reason. All I'm doing at the
moment is re-insulating the tank.

I just meant that's why the unanimity - everyone must remember the
instructions.


--
*I never drink anything stronger than gin before breakfast *

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