19
GAS SUPPLY PIPING
Before connecting the gas supply pipe, check
the UNIT NAMEPLATE to confirm that it is
compatible with the gas type available.
The gas piping must be selected and
installed in accordance with local building codes
and the National Fuel Gas Code (ANSI Z233.1,
latest edition). Typically, the pipe size is selected
at the maximum gas pressure input and with 0.5
inches water column maximum pressure loss
between the gas meter and the equipment.
CAUTION
TO AVOID DAMAGE TO THE GAS VALVES IN
THE CHILLER-HEATER, DISCONNECT THE
GAS PIPE WHEN THE TEST PRESSURE
EXCEEDS 0.5 PSI (3.4 kPa).
Allowable supply gas pressure range:
7 – 10.5 inches water column
The maximum and rated gas pressures are
measured when the burner is operating at 100%
fire rate. Install a manual shut-off valve and a
sediment trap within 6 feet of the equipment.
A gas meter is recommended in order to
facilitate burner setup when the primary gas
meter is remote from the installation site, or when
multiple gas-fired appliances exist on the supply
lines. This optional gas meter allows for gas
volume determination without the need to isolate
other appliances during burner setup.
Installation of an appliance regulator is also
recommended, especially when multiple gas-fired
appliances exist on the supply lines. This
optional appliance regulator should be sized to
handle the 100% fire rate gas supply and should
be located as the last item in the gas supply line
before it enters the chiller-heater.
The minimum gas supply pressure is 7” wc at
the burner gas valve. The maximum gas supply
pressure is 10.5” wc at the burner gas valve.
Combustion with supply gas pressure outside of
this range could cause an incorrect flame shape
in the High Temperature Generator (HGE) and
could potentially cause damage to the HGE itself.
The gas pipe connection on the chiller-heater
does NOT mean that size is appropriate for
bringing the proper volume of gas to the unit.
The gas supply piping must be capable of
carrying the total MBtuh/hr capacity of all gas-
fired appliances on the line when each is fired
simultaneously at full firing rates. Reduce to the
chiller-heater’s required pipe size attachment as
close to unit as is reasonably possible.
Gas Piping Pressure Drop Data – Mbtu/hr Capacity
Equivalent
Length of
Straight
Pipe Size
1-1/2" 2" 2-1/2" 3"
10 1150 3050 4800 8500
20 800 2100 3300 5900
30 690 1650 2700 4700
40 560 1450 2300 4100
50 500 1270 2000 3600
60 480 1150 1850 3250
70 445 1050 1700 3000
80 410 990 1600 2800
90 390 930 1500 2600
100 370 870 1400 2500
125 335 780 1250 2200
150 300 710 1130 2000
175 280 650 1050 1850
200 260 610 980 1700
Equivalent Lengths of Pipe Fittings in Feet
1-1/2" 2" 2-1/2" 3"
Standard Ell
4.5 5.5 6.5 8
45° Ell 2 2.5 3 3.7
Tee 9 12 14 17
Correction Factors
Natural Gas
0.5 1.1
0.6 1
0.7 0.926
0.8 0.867
0.9 0.817
1 0.775
Propane-Air Mix
1.1 0.74
Propane
1.55 0.662
Butane
2 0.547
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