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INSTALLATION INFORMATION
AMI072-A
Figure 12: Gas Train Front View
Gas pressure for both Natural Gas and LPG is listed below in Table 2. Note that there is different pressure
requirements for NG and LPG. If the pressure is greater than 7kPA an over pressure shut off regulator is required.
GAS PRESSURE
NG
LPG
Maximum kPa
3.5
3.5
Minimum kPa
1.12
2.74
Table 10: Gas Supply Pressures
If the inlet test pressure is not at least 1.12kPa for Natural Gas the following may have occurred;
• Gas pipe to the unit may be under sized and/or restricted
• The Gas meter may be under sized
• The Gas regulator may be set too low
If you suspect that the gas pressure is too low contact the Gas Supply authority.
DO NO
Attempt to adjust the main supply regulator where the gas enters the premises
For dual heat exchanger units a separate gas supply shall be provided to each gas train with individual isolation valves
provided.
3.4.2 LPG
Adequate sizing and the number of LPG bottles is of high importance when considering an LPG unit. Pressures can
dramatically drop as the bottles become empty. This can affect the combustion process within the unit causing light
back and poor combustion leading to excessive emissions.
3.4.3 Gas Supply for Dual Heat Exchangers
Dual heat exchanger units have 2 independent gas valves and control systems therefore require 2 separate gas supply
connections. Each gas supply requires an isolation valve and shall be individually commissioned. Pipework to the
unit shall be sized so that the pressure and gas flow is sufficient so that both heat exchanges may be operated at the
maximum output simultaneously.
3.4.4 Gas Train Information
The Gas Train as pictured in Figure 12 is installed as part of the unit. It is the responsibility of the installer to provide the
pipework to the gas train and ensure that the supply pipework is of adequate size and pressure.
When connecting the gas pipe, there may be an accumulation of condensates and other deposits in the gas pipe.
These must be cleared before connecting the gas pipe to the unit.
Purge all air from the gas pipe and check for leaks using a soap and water solution or approved leak test method.
The connections along the gas train should also be checked to ensure that there was no damage caused during
transportation and installation of the unit.
MODULATING
MOTOR
GAS VALVE
INJECTOR
BURNER
