LAARS Mighty Therm PH (Sizes 500-1825) - Installation, Operation and Maintenance Instructions - Manual (Page 11)

Mighty Therm Hydronic Boiler Page 11
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 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 12), 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.
5. Check piping diagrams with local applicable
plumbing, heating and building safety codes.
6. 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.
7. Install manual and/or automatic bleeding devices
at high points in the system to eliminate air.
Install a correctly sized air charger and tank
drainer, as appropriate.
2G. Filling Fully-Connected System
1. Close all bleeding devices and open make-up
water valve. Allow system to fill slowly.
2. If make-up water pump is employed, adjust
pressure switch on pumping system to provide a
minimum of 12 psi at the highest point in the
heating loop.
3. If a water pressure regulator is provided on the
make-up water line, adjust the pressure regulator
to provide at least 12 psi at the highest point in
the heating loop.
4. Open bleeding devices on all radiation units at
the highest points in the piping throughout the
system, unless automatic air bleeders are
provided at such points.
5. Run system circulating pump for a minimum of
30 minutes with the boiler shut off.
6. Open all strainers in the circulating system and
check for debris.
7. Recheck all air bleeders as described in Step 4
above.
8. Check liquid level in expansion tank. With the
system full of water and under normal operating
pressure, the level of water in the expansion tank
should not exceed 1/4 of the total, with the
balance filled with air.
9. Start up boiler according to procedure described
in Section 3B. Operate the entire system,
including the pump, boiler, and radiation units
for one (1) hour.
10. Recheck the water level in the expansion tank. If
the water level exceeds 1/4 of the volume of the
expansion tank, open the tank drainer and drain
to that level.
11. Shut down the entire system and vent all
radiation units and high points in the system
piping as described in Step 4 above.
12. Close make-up water valve and check strainer in
pressure reducing valve for sediment or debris
from the make-up water line. Reopen make-up
water valve.
Figure 12. Pressure Relief Valve Location.
Pressure
Relief Valve
Special attention must be given to relief valve
settings in installations where the boiler is
located on the ground floor of a tall building,
The static pressure of the system is elevated and
could cause the relief valve to leak. Where no
special setting of the relief valve is ordered, the
factory will furnish a 75 psi setting. Never
reduce the relief valve openings.
3. Pressure relief valve lever must be tripped at
least once a year to insure that waterways are
clean. When manually operating lever, water
will discharge through drain line. Precautions
must be taken to avoid contact with hot water
and water damage.
4. The weight of all water and gas piping should be
supported by suitable hangers or floor stands.