Instruction manual
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GAS SUPPLY PIPING
  Check the boiler/water heater rating plate to make 
sure that the boiler/water heater is for the type of gas 
that will be used. If it isn’t, do not connect the boiler/
water heater to the gas supply. Gas supply piping must 
be in accordance with the National Fuel code, ANSI 
Z223.1-latest revision or applicable provisions of the 
local building codes. Canadian installations must 
comply with CAN/CGA B149.1 or .2 Installation 
Code. Failure to comply with this warning can result 
in extensive property damage, severe personal injury 
or death!
  e LCD comes from the factory ready to be piped to the gas 
supply. If for any reason the boiler/water heater is not for the type 
of gas available at the installation site, call your RBI Water Heaters 
representative to resolve the problem.
  A minimum gas supply pressure of 6 in, 152 mm, 
WC natural or 11 in, 279 mm WC propane and 
maximum 14 in, 356 mm WC natural or propane, 
must be available at the safety shuto  valve inlet with 
the unit(s) operating. 
Table 10 should be used to ensure that the gas supply piping is 
sized properly. If more than one appliance is supplied by the same 
supply pipe, the piping must be sized based on the maximum possible 
demand. Do not neglect the pressure drop due to pipe   ings. Table 
10 should be used in conjunction with Table 11 to ensure that the 
gas supply piping has the capacity to meet the demand.
Figure 16 depicts the proper way to connect the boiler/ 
water heater to the gas supply piping.  e manual shut-o  valve 
must be installed in the supply piping. It should be installed 5  , 
1.5 m above the  oor where required by local codes. Provide a 
sediment trap at the bo om of the vertical section of the gas supply 
pipe upstream of the gas controls.
A ground joint union should be installed between the boiler gas 
controls and the supply piping. Each of these items are needed to 
ensure long life and ease of servicing. Always use a pipe sealant that 
is suitable for use with LP gas.
Table 10  Gas pipe capacity
Maximum pipe capacity in ft
3
/hr based on 0.60 speci c gravity gas
at a pressure of 0.5 psig or less and a 0.3" WC pressure drop. 
Nominal
Iron Pipe
Size
Pipe length in feet
10 20 30 40 50 60 80 100 150
Maximum gas volume of pipe, (ft
3
/hr)
3/4" 278 190 152 130 115 105 90 79 64
1" 520 350 285 245 215 195 170 150 120
1 1/4" 1050 730 590 500 440 400 350 305 250
1 1/2" 1600 1100 890 760 670 610 530 460 380
2" 3050 2100 1650 1450 1270 1150 990 870 710
2 1/2" 4800 3300 2700 2300 2000 1850 1600 1400 1130
3" 8500 5900 4700 4100 3600 3250 2800 2500 2000
Note:  Multiply the gas volume by 0.62 for propane  ow capacity in ft
3
/hr.
Multiply the propane  ow capacity by 2500 Btu/ft
3
 to determine
the propane Btu/hr capacity for a given pipe size and length.
Table 11  Equivalent pipe length chart
Nominal
Iron Pipe
Size
Type of pipe  tting
90˚ Elbow Tee
1
Gate Valve
2
Gas Cock
2
Equivalent pipe length, (ft)
1" 2.6 5.2 0.6 1.5
1 1/4" 3.5 6.9 0.8 1.9
1 1/2" 4.0 8.0 0.9 2.3
2" 5.2 10.3 1.2 3.0
2 1/2" 6.2 12.3 1.4 3.7
3" 7.7 15.3 1.8 4.5
Notes:  1. For  ow through branch.
  2. For  ow at full open.
  Always use a wrench on the gas valve body when 
making gas connections to it. Never over-tighten the 
piping entering the gas valve body or gas valve failure 
may result!
Figure 16  Gas supply piping
When applicable, provisions for vent, bleed and gas relief lines must 
be made in accordance with the latest revision of ANSI Z223.1/
NFPA 54.
Safe lighting and other performance criteria were met with the gas 
manifold and control assembly provided on the boiler. All gas 
connections MUST be leak tested before pu ing the boiler into 
operation.
  Never use an open  ame to test for gas leaks. Always 
use an approved leak detection method. Failure to 
comply with this warning can cause extensive property 
damage, severe personal injury or death!
Whenever the gas supply piping is pressure tested the boiler/water 
heater gas controls must be protected. If the test pressure is equal 
to, or less than 1/2 psig, 3.5 kPa isolate the boiler/water heater 
by closing it's manual shut o valve, see Figure 16. If the test 
pressure is greater than, or equal to 1/2 psig, 3.5 kPa, disconnect 
the boiler/water heater and its individual shut-o valve.










