Hi

I ahve a Glow worm Swift Flow 100E combi boliler that is driving me nuts.
The problem manifests itself as a problem with supplying hot water to the
shower. It seems to heat the water well initially and provides an adequate
flow of water to have a comfortable shower but then after a minute or two
of running the water will go cold for 20 seconds or so before getting hot
again. It is not caused by any of the normal suspects such as somebody
turning a tap on or the dishwasher/washing machine switching on as these
are all off. Nor is it the thermostatic valve in the shower unit as I can
feel that the supply to the valve is absolutely stone cold. I thought it
may be caused by the central heating demanding heat but even with the CH
turned off the problem remains.

I don't have any form of manual for the boiler which doesn't help (anybody
know where I can get one in electronic form?) but is there perhaps an water
overheat thermostat that is faulty somewhere in the system? Any
suggestions welcome as I am getting hacked off with dancing in and out of
the shower as the temp fluctuates.
--
Take out the garbage to reply

Regards
Tony Hogarty

"Tony Hogarty" wrote in message
...
Hi

I ahve a Glow worm Swift Flow 100E combi boliler that is driving me nuts.
The problem manifests itself as a problem with supplying hot water to the
shower. It seems to heat the water well initially and provides an
adequate
flow of water to have a comfortable shower but then after a minute or two
of running the water will go cold for 20 seconds or so before getting hot
again. It is not caused by any of the normal suspects such as somebody
turning a tap on or the dishwasher/washing machine switching on as these
are all off. Nor is it the thermostatic valve in the shower unit as I can
feel that the supply to the valve is absolutely stone cold. I thought it
may be caused by the central heating demanding heat but even with the CH
turned off the problem remains.

Does this occur when filling the bath? If not then it appears the shower is
the culprit. I generally don't like thermostatic mixers with combi's. The
pressure balanced showers are best.

I don't have any form of manual for the boiler which doesn't help (anybody
know where I can get one in electronic form?) but is there perhaps an
water
overheat thermostat that is faulty somewhere in the system? Any
suggestions welcome as I am getting hacked off with dancing in and out of
the shower as the temp fluctuates.
--
Take out the garbage to reply

Regards
Tony Hogarty

water to the shower. It seems to heat the water well initially and
provides an adequate flow of water to have a comfortable shower but
then after a minute or two of running the water will go cold for 20
seconds or so before getting hot again.

This can happen if your combi isn't modulating properly, (or is a
non-modulating type). What happens is that the temperature rises and rises
until the main boiler thermostat kicks in and turns off the burner until it
reduces again. It takes a good 20 seconds to relight the boiler when the
temperature recovers (which will be almost immediately).

If the boiler is non-modulating, then your only hope is to increase the
water flow. This might be achieved by installing a wider bore hose on the
shower or a power shower head with larger holes. You could experiment by
leaving a basin hot tap on slightly to see if it cures the problem.

Christian.

"Tony Hogarty" wrote in message
...
Hi

I ahve a Glow worm Swift Flow 100E combi boliler

I don't have any form of manual for the boiler which doesn't help (anybody
know where I can get one in electronic form?)


There's no literature available (and a search produced no results) for
"swift flow" on the Glow worm site. However "100E" produced this. Dunno
whether its what you were looking for however :-)
http://www.glow-worm.co.uk/epower/gw...ct100E_UIS.pdf

--

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Paul King wrote:

"Tony Hogarty" wrote in message
...
Hi

I ahve a Glow worm Swift Flow 100E combi boliler

I don't have any form of manual for the boiler which doesn't help
(anybody know where I can get one in electronic form?)


There's no literature available (and a search produced no results) for
"swift flow" on the Glow worm site. However "100E" produced this. Dunno
whether its what you were looking for however :-)
http://www.glow-worm.co.uk/epower/gw...df/nc_products
Compact100E_UIS.pdf


It is certainly very similar thanks. I'll have a more detailed look in the
morning and see exactly how close it is - the controls are different but
the physiacal layout of the boiler looks close on first impressions.
--
Take out the garbage to reply

Regards
Tony Hogarty

On Tue, 09 Mar 2004 15:32:46 +0000, Christian McArdle wrote:

water to the shower. It seems to heat the water well initially and
provides an adequate flow of water to have a comfortable shower but
then after a minute or two of running the water will go cold for 20
seconds or so before getting hot again.

This can happen if your combi isn't modulating properly, (or is a
non-modulating type). What happens is that the temperature rises and rises
until the main boiler thermostat kicks in and turns off the burner until it
reduces again. It takes a good 20 seconds to relight the boiler when the
temperature recovers (which will be almost immediately).

If the boiler is non-modulating, then your only hope is to increase the
water flow. This might be achieved by installing a wider bore hose on the
shower or a power shower head with larger holes. You could experiment by
leaving a basin hot tap on slightly to see if it cures the problem.

IME this problem most likely (there are several possible causes) is caused
by limescale build up on the DHW side of the secondary heat exchanger.
The boiler simply can't transfer enough heat without over heating so it
shuts down temporarily.

Other causes a
Out of calibration temperature sensors.
Gas valve modulation control faulty.
Too little flow of HW (but enough to start the boiler).

A work around which may help is to turn down the HW thermostat (assuming
this is distinct from the CH thermostat). This may help to bring the
boiler into a steadier state, until the real cause can be tackled.











--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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