Glow-worm Xtramax - Manual (Page 12)

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COLD WATER
SUPPLY
A B C D E
D1
1 - Domestic thermistor
2 - Three way valve
3 - Gas control valve
4 - Ignition unit
5 - Temperature sensor for
DHW storage vessel
6 - DHW storage vessel
7 - Burner
8 - Ignition electrode
9 - Combustion chamber
10 - Heating safety valve (3 bar)
11 - Main heat exchanger
12 - Air pressure switch
13 - Water flow sensor
14 - DHW pump
15 - Non return valve
16 - Bypass
17 - Domestic plate to plate heat
exchanger
18 - Heating pump
19 - Heating expansion vessel
20 - Heating thermistor
21 - Overheat safety thermostat
22 - Flame sense electrode
23 - Fan
24 - Expansion valve (6 bar)
25 - Water pressure sensor
26 - Domestic expansion vessel (3.5
bar)
27 - Temperature pressure/ relief valve
(7 bar/90°C)
28 - Pressure reducing valve and
Check valve.
Max. supply pressure 16 bar.
(Supplied)
Diagram 5.1
11749
4 Domestic Hot Water System Design
• Copper tubing or plastic Hep
2
0 may be used for the domestic
hot water system. Unnecessary pressure losses should be
avoided.
• A flow restrictor limiting the flow through the boiler to a
maximum of 16 l/min is fitted to the boiler.
• The boiler will operate with a minimum supply pressure of 0,7
bar, but under reduced flow rate.
Best operating comfort will be obtained from a supply pressure
of 1 bar.
4.1 Hard Water Areas
In areas where the water is 'hard', more than 200mg/litre, it is
recommended that a proprietary scale reducer is fitted in the
cold water supply to the boiler.
A pressure reducing valve for the cold water inlet supply is
provided, this is packed inside the boiler. This valve is a
necessary part of the unvented system and MUST be fitted to
the cold water supply, see diagram 8.1.
4.2 Domestic hot water drain point
The DHW drain point is located below the DHW pump, see
diagram 4.1.
Diagram 4.1
9527
A - Heating return
B - Cold water inlet
C - Heating flow
D - Domestic hot water outlet
E - Gas
D1 - Discharge from HTG
safety valves
D2 - Discharge from temp/press
and expansion valve (to tundish)
5 Boiler Schematic