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Andy Coleman
 
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Default Problem with water tempature and a Worcester 28CDi combi

Hi,

We had a new heating system installed a couple of years ago and I have
noticed an issue with the water temapture.

My wife was commenting a couple of days ago that the water tempature
in the bathroom was not very good and could be described as warm
rather than hot. I checked the preasure on the Worcester combi boiler
and it was around about 1bar when there was no demand. Last night I
refilled the system so that the dial is now reading about 1.5bar. Now
the last time I did this it sorted the problem.

But this time it seems to have not completely done the trick. The
temapture of the water in the kitchen was hot but in the bathroom it
was still only warm. This puzzeled me as I cannot see how the water
coming from the same boiler can be different between the bathroom and
kitchen. Our bathroom is directly above the kitchen so it is not as
though the water has far to go.

Incidentaly we never get a problem with the radiators - they are
always the correct tempature.

Thanks
Andy
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Richard Markham
 
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Default Problem with water tempature and a Worcester 28CDi combi

In article , Andy
Coleman writes
Hi,

We had a new heating system installed a couple of years ago and I have
noticed an issue with the water temapture.

My wife was commenting a couple of days ago that the water tempature
in the bathroom was not very good and could be described as warm
rather than hot. I checked the preasure on the Worcester combi boiler
and it was around about 1bar when there was no demand. Last night I
refilled the system so that the dial is now reading about 1.5bar. Now
the last time I did this it sorted the problem.

But this time it seems to have not completely done the trick. The
temapture of the water in the kitchen was hot but in the bathroom it
was still only warm. This puzzeled me as I cannot see how the water
coming from the same boiler can be different between the bathroom and
kitchen. Our bathroom is directly above the kitchen so it is not as
though the water has far to go.

Incidentaly we never get a problem with the radiators - they are
always the correct tempature.

Thanks
Andy


I have the same boiler and a similar problem...

The diverter valve controls the flow of cold water going into the heat
exchanger and also the circulation of the heated CH water into the
exchanger.

The operation of this valve depends on a pressure differential between
the cold water supply and the pressure in the pipes going to the hot
taps. when you open a hot tap, the pressure drops on one side and the
valve moves. When it moves, it allows cold water to pass into the heat
exchanger, it also switches the CH circuit to go around the heat
exchanger and finally, it operates the flow switch which ignites the
burner.

There is also manually adjustable flow valve where the water leaves the
diverter and goes into the heat exchanger. This allows you to reduce the
hot water flow rate, which in turn allows it to spend more time in the
exchanger getting hotter.

It's all a delicate balance.

What's the flow rate like when the taps are full on? If one tap allows
more to flow, the water will be cooler. If a tap doesn't allow enough
flow, the water will be stone cold. I think 10L per min is the max flow.

If anyone knows any more about these things, let me know!

I'd like to know why our boiler needs to see 6L/min flow before it even
thinks about heating the hot water! The spec says 2.5-3L/min.
--
Richard Markham
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Alan Campbell
 
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Default Problem with water tempature and a Worcester 28CDi combi

Hi,

I had a similar problem a month or so back with my Worcester
Greenstar. I checked a couple of obvious things such as the controller
settings etc - no joy so I resigned myself to a weekend tracking an
airlock or something.

Anyway, luckily my wife told me that she had cleaned the boiler. Mmmm
I thought - took a look at the front panel and she had managed to turn
the thermostat fully down. I hadn't expected anything _that_ obvious.

I've no idea how the radiators were still hot and the water was wasn't
though...

Alan.

(Andy Coleman) wrote in message . com...
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