Mighty Therm Lo-Nox
Page 7
Distance from Gas Meter
or Last Stage Regulator
Size
0-100'
100-200'
200-300'
500
1½"
2"
2"
715
2"
2"
2½"
1010
2"
2½"
3"
1430
2½"
3"
3"
1825
2½"
3"
3½"
NOTE: These figures are for Natural Gas (.65 Sp. Gr.), and are
based on 1/2" water column pressure drop. Check supply
pressure with a manometer, and local code requirements for
variations. An average number of tees and elbows have been
taken into account.
Table 3. Gas Piping Sizes.
are normally equipped to operate below a
2000 foot (609.6m) altitude. Heaters equipped to
operate at higher altitudes have appropriate
stickers or tags attached, also printed information
on rating plate.
2.
Use the figures in Table 3 to provide adequate
gas piping from the gas meter to the heater.
Figure 6. Sediment Trap Installation.
7.
The gas manifold and control assembly is
factory tested and conforms to the safe lighting
and other performance criteria specified in the
latest editions of ANSI Z21.13 and CGA 3.3
Low Pressure Boiler Standard.
8.
Before operating the heater, test the complete gas
supply system and all connections for leaks using
a soap solution. Do not use raw flame.
Caution
Since some leak test solutions (including soap
and water) may cause corrosion or stress
cracking, the piping must be rinsed with water
after testing, unless it has been determined
that the leak test solution is noncorrosive.
2.5 Electrical Wiring
WARNING
The heater must be electrically grounded in
accordance with the most recent edition of the
National Electrical Code, ANSI/NFPA 70. In
Canada, all electrical wiring to the boiler should
be in accordance with the latest edition of CSA
C22.1 Canadian Electrical Code, Part 1. Do not
rely on the gas or water piping to ground the
metal parts of the boiler. Plastic pipe or
dielectric unions often isolate the heater
electrically. Service and maintenance
personnel who work on or around the heater
may be standing on wet floors and could be
electrocuted by an ungrounded heater.
Wiring diagrams are included in the information
packet provided with each unit.
1.
All Laars heaters need 115V 60Hz supply
voltage unless specifically ordered otherwise.
3.
A sediment trap (drip leg) must be provided
ahead of the gas controls (see Figure 6). A
manual gas shutoff valve must also be provided
for service convenience and safety. A cap must
be provided for cleaning purposes. Check the
local codes.
4.
The heater and its individual shutoff valve must
be disconnected from the gas supply piping
system during any pressure testing of that system
at test pressures in excess of 1/2 psig. The heater
must be isolated from the gas supply piping
system by closing its individual manual gas
shutoff valve during any pressure testing of the
piping system at test pressures equal to or less
than 1/2 psig.
5.
Provide gas supply pressure to the heater as
follows:
Natural
Gas
Max. (inches water column)
10
Min. (inches water column)
6.5
NOTE: the heater and all other gas appliances sharing
the boiler gas supply line must be firing at maximum
capacity to properly measure the inlet supply pressure.
Low gas pressure could be an indication of an
undersized gas meter and /or obstructed gas supply
line.
6.
The correct burner manifold gas pressure is
stamped on the rating plate. The regulator is
preset at the factory and normally requires no
further adjustment.
