LAARS Mighty-Stack TL00-199 - Installation, Operation and Maintenance Instructions - Manual (Page 11)

Mighty Stack Water Heater Page 11
Figure 11. Location of Parts in Control Box.
WARNING
The boiler must be electrically grounded. Follow the
requirements of the local authority having
jurisdiction. In the absence of such requirements,
follow the latest edition of the National Electrical
Code ANSI/NFPA 70 in the U.S., or the latest
edition of CSA C22.1 Canadian Electrical Code,
Part 1, in Canada. Do not rely on the gas or water
piping to ground the metal parts of the boiler.
Plastic pipe or dielectric unions may 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 an ungrounded boiler.
3. The 3 position switch is configured as follows:
Middle Position
All power to the unit is shut
off.
‘Down’ Position Boiler On, pump in automatic
mode. The pump will shut off
3 minutes after the call for
heat is satisfied.
‘Up’ Position Boiler On, pump in constant
mode. The pump will
continue to run after the call
for heat is satisfied.
4. To make the wiring connections, remove the two
screws which attach the front cover of the
control box.
5. There are two sets of wires near the top of the
control box (see Figure 11). These wires are for
connection to the 115V AC lines. Connect the
hot lead from the 115V power supply to the
black wire. Connect the three white wires to the
neutral side of the 115V line (see Figure 12).
1P. Filling the Contractor Supplied
Storage Water Tank
Caution
Air must be removed from the heater and the tank
before the unit is operated. If this is not done, the
heat exchanger may be damaged.
1. Open the hot water faucet(s) to allow air to
escape.
2. Open the shut-off valve(s) in the cold water
supply line.
3. Open the shut-off valve(s) in the hot water
supply line.
4. Turn off the gas to the unit, but allow the pump
to run for about 15 minutes. This will allow any
remaining air to collect in the top of the tank.
5. Open the pressure relief valve to remove any
remaining air.
6. Turn on the gas and check for leaks. Now the
unit is ready to operate.
1Q. Water Condition and Pump
Requirements
Laars equipment is designed to be used in a
variety of water conditions. With the proper pump, the
water velocity within the heat exchanger tubes is kept
high enough to prevent scaling from hard water, and
low enough to avoid erosion from soft water.
Water hardness must be considered when
selecting a pump for this unit. Table 9 identifies the
water hardness categories and their hardness
composition.
Hardness Grains per Parts per
Category Gallon Million
Soft 1 through 7.5 17 through 128
Normal 7.6 through 17 129 through 291
Hard Over 17 Over 291
Table 9. Water Hardness.
This unit is designed to operate with inlet water
temperatures that are greater than 100°F. Water
temperatures greater than this will ensure that
condensation of flue gas inside the combustion
chamber is greatly minimized.