Hi,

I've got a problem in my house. Yesterday we decided to turn central
heating on.
On ground floor all radiators are OK, but first floor ones remain cold.
I am going to try to check if there any air stuck in them.
But if not, what else can I do?
If it is important; we have a boiler in the kitchen downstairs and
water tank is on the first floor.

Many thanks.

In an earlier contribution to this discussion,
wrote:

Hi,

I've got a problem in my house. Yesterday we decided to turn central
heating on.
On ground floor all radiators are OK, but first floor ones remain
cold. I am going to try to check if there any air stuck in them.
But if not, what else can I do?
If it is important; we have a boiler in the kitchen downstairs and
water tank is on the first floor.

Many thanks.

Assuming you've got a vented (not sealed) system, you will have 2 tanks in
the attic - a large cold water header tank for the hot water system, and a
small fill & exansion (F&E) tank for the heating system's primary
circulation circuit.

Chances are that the ball valve has stuck on the F&E tank - and that it has
failed to open in order to make up the water level to compensate for
evaporation an/or slow leakage. So check that first, and make sure that the
outlet pipe at the bottom of the tank is covered by 2 or 3 inches (it
doesn't need a lot) of water, and that water flows when you press the ball
down.

Then bleed the upstairs radiators. If that doesn't work, you may still have
some air trapped in the pipes. You can often free this by turning off all
the rads, and turning on just one problem rad at a time - so that the full
pump output is directed through it.
--
Cheers,
Set Square
______
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Set Square wrote:
Then bleed the upstairs radiators. If that doesn't work, you may still have
some air trapped in the pipes. You can often free this by turning off all
the rads, and turning on just one problem rad at a time - so that the full
pump output is directed through it.
--

I was just about to post a similar question - my downstairs rads are
cold, the upstairs only warm. This seems to be causing my boiler to
trip out with it's overheat protection. It's a Keston 130 and seems
sensitive to this, it's also been blowing water out throught the vent
valve.

In an earlier contribution to this discussion,
wrote:

Set Square wrote:
Then bleed the upstairs radiators. If that doesn't work, you may
still have some air trapped in the pipes. You can often free this by
turning off all the rads, and turning on just one problem rad at a
time - so that the full pump output is directed through it.


I was just about to post a similar question - my downstairs rads are
cold, the upstairs only warm. This seems to be causing my boiler to
trip out with it's overheat protection. It's a Keston 130 and seems
sensitive to this, it's also been blowing water out throught the vent
valve.

Do you mean that it's a non-vented (pressurised) system - and that it's
discharging water through it's safety pressure-release valve?

If so, you've almost certainly got a problem with the expansion vessel. With
the water system at zero pressure, check the gas pressure in the expansion
vessel using a car-type pressure gauge. If water comes out of the Schrader
valve, the diaphragm is shot, and you need a new expansion vessel. If water
*doesn't* come out, but the pressure is low, pump some air in with a car
tyre pump, until the pressure is about 0.7 bar (10 PSI). Then connect the
filling loop (it *isn't* connected all the time, is it?!) to pressurise the
wet system to 1 Bar (cold). Hopefully, when the system heats up, the
pressure will remain under 2 Bar - with no further loss of water, and all
the rads will work. They may need bleeding again - after which you may need
to top up the pressure again with the filling loop.
--
Cheers,
Set Square
______
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Set Square wrote:

Do you mean that it's a non-vented (pressurised) system - and that it's
discharging water through it's safety pressure-release valve?

yes it's pressurised but i'm not sure which valve is releasing. There
is a pipe that runs to the outside of the house which can be used to
manually dump water from the system (and i suspect is the safety
pressure release you're talking about).

There is also, on the pipe above the boiler, a little pot shaped thing
(a bit bigger than a 35mm film canister) with a red plastic knob on top
that can be screwed down. the last time we had an engineer in (to
reroute some pipes) he unscrewed this, which must have been closed
since we moved in) and said it should be open. i understood this was
to let air out of the system - it's this valve that's been blowing a
bit of water.

In an earlier contribution to this discussion,
wrote:

Set Square wrote:

Do you mean that it's a non-vented (pressurised) system - and that
it's discharging water through it's safety pressure-release valve?

yes it's pressurised but i'm not sure which valve is releasing. There
is a pipe that runs to the outside of the house which can be used to
manually dump water from the system (and i suspect is the safety
pressure release you're talking about).

There is also, on the pipe above the boiler, a little pot shaped thing
(a bit bigger than a 35mm film canister) with a red plastic knob on
top that can be screwed down. the last time we had an engineer in (to
reroute some pipes) he unscrewed this, which must have been closed
since we moved in) and said it should be open. i understood this was
to let air out of the system - it's this valve that's been blowing a
bit of water.

OK, I may have misunderstood.

AIUI, the valve you describe should only be open for a while after initial
fill until all the air is purged, and then kept closed.

What pressure is the pressure guage showing when the system is (a) cold and
(b) hot? The filling loop *is* disconnected, isn't it?

Does your system have inhibitor in it? Do you get air collecting in the
radiators?
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

On Mon, 07 Nov 2005 08:54:14 -0800, b33k34 wrote:


Set Square wrote:

Do you mean that it's a non-vented (pressurised) system - and that it's
discharging water through it's safety pressure-release valve?

yes it's pressurised but i'm not sure which valve is releasing. There
is a pipe that runs to the outside of the house which can be used to
manually dump water from the system (and i suspect is the safety
pressure release you're talking about).

There is also, on the pipe above the boiler, a little pot shaped thing
(a bit bigger than a 35mm film canister) with a red plastic knob on top
that can be screwed down. the last time we had an engineer in (to
reroute some pipes) he unscrewed this, which must have been closed
since we moved in) and said it should be open. i understood this was
to let air out of the system - it's this valve that's been blowing a
bit of water.

That's an auto air vent. See the Sealed CH system FAQ below for full
details. Especially the section about never filling up.


--
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