LAARS Mighty Therm HH (Sizes 2000-5000) - Installation, Operation and Maintenance Instructions - Manual (Page 9)

Mighty Therm Hydronic Boiler Page 9
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.
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.
Arrangement of gas train components for on-off,
2-stage and 4-stage firing are shown schematically in
the Gas Piping Diagram (see Figure 8).
2F. Electrical Wiring
(electrical diagrams are included with the packet
provided with each unit)
WARNING
The boiler must be electrically grounded in
accordance with the most recent edition of the
National Electrical Code, ANSI/NFPA 70 and, in
Canada, follow Canadian Electrical Code CSA
C22.1. Do not rely on the gas or water piping to
ground the metal parts of the boiler. Many times,
plastic pipe or dielectric unions isolate the boiler
electrically. Service and maintenance personnel
who work on or around the boiler may be standing
on wet floors and could be electrocuted by a poorly
grounded boiler.
1. Check boiler wiring and pump for correct
voltage, frequency and phase. If the pump circuit
is other than 115V, check to see that the boiler is
provided with an appropriate transformer.
2. Wire the boiler and pump exactly as shown in
the wiring diagram supplied with the boiler.
3. The pump and boiler must be electrically
interlocked so the boiler 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 boiler wiring at points
shown in the wiring diagram designated “Field
Interlock.”
2G. Piping of System to Boiler
1. Be sure to provide gate valves at the inlet and
outlet to the boiler so it can be readily isolated
for service.
2. The pressure relief valve must be installed in the
tapped opening provided in the boiler header
with its outlet piped to a drain or floor sink.
Special attention must be given to relief valve
settings in installations where the boiler is
located on the ground floor of a tall building, or
where the operating temperature of the boiler is
above 210°F. In both instances, the static
pressure of the system is elevated, and could
cause the relief valve to leak and bring
considerable raw water into the system. Where
no special setting of the relief valve is ordered,
the factory will furnish a 125 psi setting. Never
reduce the relief valve opening. If necessary,
install the relief valve in a Tee immediately past
the boiler outlet.
3. A boiler installed above radiation level must be
provided with a low water cutoff device either as
part of the boiler or at the time of boiler
installation (see Figure 9).
4. Install manual and/or automatic bleeding devices
at high points in the system to eliminate air.
Install a correctly sized expansion or
compression tank with suitable air charger and
tank drainer, as appropriate.
5. The weight of all water and gas piping should be
supported by suitable hangers or floor stands.
6. Check piping diagrams with local applicable
plumbing, heating and building safety codes.
Pilot Gas Valve**
To Pilot
To Pilot
To Main
Burners
To Main
Burners
Main Gas Valve†
Pilot Gas Valve**
Main Gas Valve†
Hi-Pressure
Switch*
Pilot Gas Filter
A
Manual
Gas
Valve
B
Manual Pilot
Gas Valve
Pilot Gas
Pressure Regulators
Safety
Solenoid
Valve(s)
Note:
Main Gas Valves
Incorporate Gas
Pressure Regulators
* Standard on sizes 3050-5000 (AGA models).
** Sizes 2000 & 2450 use one pilot gas valve.
† Sizes 2000, 2450 & 3050 with on-off or two stage fire, use
one main gas valve.