Water Supply - Worcester Greenstar 4000 Installation And Maintenance Instructions Manual

Pipe sizing (NG & LPG)
Gas pipework:
▶ Gas installation pipework must be designed to ensure the pressure
loss between the meter outlet (NG) or storage and regulator (LPG)
and the inlet to each appliance does not exceed 1mbar (NG) 2.5mbar
(LPG) ( table 21 "Allowed mbar pressure drop").
Basic pipe sizing calculation
Basic pipe sizing calculation.
▶ This method is only an estimate - for more complex design please
refer to latest version of BS6891 and training given in ACS.
Natural Gas (NG):
Discharge rates for copper tube with 1mbar differential pressure
between the ends for Natural Gas.
Discharge rates for Natural Gas (m
with straight horizontal copper tube
Pipe
length (m)
3
6
9
12 Discharge
3
15 m /hr
20
25
30
Table 9 Natural Gas (NG)
Natural Gas:
▶ When using this table to estimate the gas flow rate in pipework of a
known length, the effective length will be increased by 0.5m for each
90° elbow and tee fitted and by 0.3m for each 45° bend.
Liquid Petroleum Gas (LPG):
Discharge rates for copper tube with 2.5mbar differential pressure
between the ends for LPG.
Discharge rates for LPG (m
with straight horizontal copper tube
Tubing
length (m) 15mm
3
kW m /hr
3 38.4 1.49
6 26.1 1.01
9 20.5 0.79
12 17.9 0.70
15 15.5 0.60
18 13.5 0.53
21 12.9 0.50
24 12.0 0.47
Table 10 Liquid Petroleum Gas (LPG)
Greenstar 4000 – 6 720 891 161 (2020/09)
3
/hr)
Pipe size (mm)
15 22 28
2.9 8.7 18
1.9 5.8 12
1.5 4.6 9.4
1.3 3.9 8
1.1 3.4 7
0.95 2.9 5.9
0.92 2.5 5.2
0.88 2.3 4.7
3
/hr & kW)
Outside diameter
22mm 28mm
3
kW m /hr kW
207 8.01 412
135 5.21 230
108 4.19 215
94 3.62 187
82 3.20 168
74 2.86 145
67 2.58 135
61 2.58 126
Liquid Petroleum Gas (LPG):
▶ When using this table to estimate the Gas flow rate in pipework of a
known length, the effective length will be increased by 0.6m for each
90° elbow or tee and by 0.3m for each 45° bend or straight coupler.
4.2.3

Water supply

Use in hard water areas:
Normally there is no need for water treatment to prevent scale formation
as the maximum temperature of the DHW heat exchanger is limited by
the electronic control.
In areas where temporary water hardness exceeds 200ppm,
consideration may need to be given to the fitting of a scale prevention
device. In such circumstances, the advice of the local water authority
should be sought.
Water mains pressure:
• Minimum mains water pressure, for maximum performance refer to
section 13.1 "Technical data".
• Maximum mains fed water static pressure is 10 bar.
If necessary fit a pressure reducing valve.
NOTICE
35
Non-return, back flow prevention devices (including those
32
associated with water meters) fitted to the mains water supply can
22
cause a pressure build up which could damage the boiler and other
17
household appliances.
15
13
NOTICE
11
Non-return valves in the cold water feed system.
9.5
8.5
If a non-return valve is fitted on the mains inlet, then pressure can
increase significantly over normal standing pressure when the appliance
carries out a DHW preheat or due to fast acting valves closing on other
appliances/outlets.
▶ To ensure water pressure stays at a level that will not damage the
boiler or other household appliances, we would recommend on
installations where standing pressure exceeds 3bar, that a 3 bar
pressure reducing valve and mini expansion vessel are fitted.
Keyless filling link accessory
Minimum static pressure.
▶ A minimum static cold water mains pressure of 1.75bar is
recommended for correct operation of the Keyless filling link.
3
m /hr
15.92
8.86
8.33
7.25
6.51
5.61
5.24
4.87
Pre-Installation
15