LAARS Heating Systems
Page 20
NOTE: This unit and all other gas appliances
sharing the gas supply line must be firing at
maximum capacity to properly measure the inlet
supply pressure. The pressure can be measured
at the supply pressure port on the gas valve.
Low gas pressure could be an indication of an
undersized gas meter, undersized gas supply
lines and/or an obstructed gas supply line.
The units may be equipped with low and high
pressure gas switches that are integrally vent
limited. These types of devices do not require
venting to atmosphere.
NOTE: After placing the boiler in operation, the
ignition system safety shutoff device must be
tested. See 10.A on page 80
SECTION 4 Gas supply and
Piping
4.A Gas Supply and Piping
All Installations must conform to the National Fuel
Gas Code ANSI Z223.1/NFPA54, and/or local codes.
In Canada, the installation must conform to the latest
edition of CSA B149.1 Natural Gas and Propane
Gas Installation Code, and/or local codes. Gas
piping should be supported by suitable hangers or
floor stands, not the appliance.
Review the following instructions before proceeding
with the installation.
1. Verify that the appliance is fitted for the proper type
of gas by checking the rating plate.
NOTE: This unit is equipped to operate at elevations
up to 2000 feet (610m). However, the unit will
function properly without the use of high altitude
modification at elevations up to 10,000 feet (3050 m).
For elevations above 2000 ft (600 m), the input gas
rating shall be reduced at a rate of 4 percent for
each 1000 ft (300 m) above sea level. This must be
considered before selecting the equipment size.
2. The gas pressure settings must match fuel type as
shown in Table 12
3. Table 13 and Table 14 on page 21 offer some
gas pipe sizing information. Refer to the applicable
gas code for more detailed sizing information.
4. Run gas supply line in accordance with all
applicable codes.
5. Locate and install manual shutoff valves in
accordance with state and local requirements.
6. A sediment trap must be provided upstream of the
gas controls.
7. All threaded joints should be coated with piping
compound resistant to action of liquefied petroleum
gas.
8. The unit and its individual shutoff valve must be
disconnected from the gas supply piping during any
pressure testing of that system at test pressures in
excess of 1/2 PSIG (3.45kpa).
9. The unit must be isolated from the gas supply
system by closing its individual manual shutoff
valve during any pressure testing of the gas supply
piping system at test pressures equal to or less
than 1/2 PSIG (3.45kpa).
10. The unit and its gas connection must be leak tested
before placing it in operation.
11. Purge all air from gas lines
Table 12. Gas Pressure by Type
Natural Gas
LP (propane)
Min
4.0 IN - W.C.
8.0 IN - W.C.
Max
10.5 IN - W.C.
14.0 IN - W.C.
WARNING
Do not use open flame to check for leaks. An open
flame could lead to explosion, which could result in
property damage, serious injury or death.
WARNING
If an inline high gas pressure regulator is used, it
must be of the lockup type and located a minimum
of 10 feet from the unit. Failure to do so may result
in insufficient gas volume
supplied to the unit.
