LAARS Mighty Therm IW (Sizes 500-1825) - Installation, Operation and Maintenance Instructions User Manual
Page 8
LAARS Heating Systems
Page 8
4.
The boiler 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 boiler must
be isolated from the gas supply piping system by
closing its individual manual gas shutoff valve
during any pressure testing of the gas supply
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
LPG
Min. (inches
water column)
Max. (inches
water column)
Note: The heater and all other gas appliances
sharing the heater 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.
7.
The gas manifold and control assembly was
tested and conform 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 boiler, the complete gas
supply system and all connections must be tested
for leaks using a soap solution. Do not use raw
flame.
Figure 8. T-Fitting Sediment Trap Installation.
Per Rating Plate
9 14
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.
2E. Electrical Wiring
WARNING
The heater must be electrically grounded in
accordance with the most recent edition of the
National Electrical Code, ANSI/NPA 70. In
Canada, all electrical wiring to the heater
should be in accordance with the Canadian
Electrical Code, CSA C22.1 Part 1. Do not rely
on the gas or water piping to ground the metal
parts of the heater. Oftentimes, plastic pipe or
dielectric unions 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
underground heater.
1.
Check heater wiring and pump for correct
voltage, frequency and phase. If the pump circuit
is other than 115V, check to see that the heater is
provided with an appropriate transformer.
2.
Wire the heater and pump exactly as shown in
the wiring diagram supplied with the heater.
3.
The pump and heater must be electrically
interlocked so the heater cannot come on unless
the pump is running.
4.
All field installed electrical safety devices and all
field installed devices (draft switches, relays,
timers, outdoor temperature reset devices, etc.)
can be connected to the heater wiring at points
shown in the wiring diagram designated “Field
Interlock”.
2F. Water Piping of System
1.
Be sure to provide valves at the inlet and outlet
of the boiler so it can be readily isolated for
service. A butterfly or similar type of valve is
recommended.
2.
The pressure relief valve installed in the tapped
opening provided in the outlet header (see
Figure 9), must be piped, but not fastened, to a
drain or floor sink. The drain pipe must be the
same size as the valve outlet and must pitch
downward from the valve.