LAARS Mighty Therm2 MT2P (Sizes 500–2000 MBTU/h) - Install and Operating Manual - Manual (Page 12)

LAARS Heating Systems Page 12
undersized gas supply lines and/or an obstructed gas
supply line. The MT2P may not fire if the gas pressure
lower than 5" w.c.
SECTION 4.
Water Connections
Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with
this appliance. Due to expansion and contraction of
copper pipe, consideration should be given to the type
of hangers used. Rigid hangers may transmit noise
through the system resulting from the piping sliding in
the hangers. It is recommended that padding be used
when rigid hangers are installed. Maintain 1" clearance
to combustibles for hot water pipes.
Pipe the discharge of the relief valve (full size) to
a drain or in a manner to prevent injury in the event of
pressure relief. Install shutoff valves where required by
code.
MT2P Pool Heaters are equipped with mounted
pumps, which serve the heater plus 30 feet of full-sized
piping with a normal number of fittings. If the pool’s
loop is more than 15 feet away from the heater, please
contact the factory.
A mixing system is shipped with the heater. The
system consists of a three-way valve, and piping. When
the control detects water temperature that is below
130°F (54°C), it will direct the three-way valve to
actuate, which sends water from the outlet of the heater
back to the inlet. The outlet water that is diverted to
the inlet mixes with the return water from the pool, and
keeps the inlet temperature at or above 120°F (49°C)
( see Figure 4 ). This keeps cold return water from
causing condensing on the outside of the MT2P heat
exchanger.
Heater return water piping may be PVC, CPVC or
copper. Because of the high temperature of heater outlet
water, it is critical that the heater outlet piping be made
of CPVC or copper.
See Figure 5 for proper connection of the MT2P
heater to the pool loop.
4.2 Automatic Chlorinators
A concentration of chlorine in the heater can be
very destructive; therefore the following rules about
the installation and operation of such devices must be
followed:
1. The chlorinator should be installed so it introduces
the gas or solution downstream of the heater.
2. The chlorinator should be wired so it cannot
operate unless the filter pump is operating.
3. The chlorinator should be provided with an anti-
siphon device so that the draining of the piping
after the pump shuts off will not siphon chlorine
solution into the heater.
4. When the operation of a chlorinator is such
that it must be installed in the pump suction, or
some other place where the chlorine solution
flows through the heater, corrosion of the heater
can occur. Excessive concentrations of chlorine
resulting from improper adjustment or chlorinator
equipment failure are responsible for this
corrosion. The heater warranty does not cover the
resulting damage to the heat exchanger.
4.3 Sensor Locations
Two sensors must be installed in the pool loop, as
shown in Figure 5. The inlet sensor for the temperature
control must be installed in the pool loop within 12”
(30 cm) of the inlet to the heater. The second sensor,
the high limit sensor, must be installed in the pool loop
within 12” (30 cm) downstream of the heater outlet.
This sensor is a capillary and bulb. It shall be used with
the immersion well that is provided.
SECTION 5.
Electrical Connections
WARNING
The appliance must be electrically grounded in
accordance with the requirements of the authority
having jurisdiction or, in the absence of such
requirements, with the latest edition of the National
Electrical Code, ANSI/NFPA 70, in the U.S. and
with 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.
Single pole switches, including those of safety
controls and protective devices must not be wired in a
grounded line.
NOTE: All internal electrical components have been
prewired. No attempt should be made to connect
electrical wires to any other location except the field
wiring strip.
5.1 Main Power
Mighty Therm 2 Pool Heater sizes 500 to 1500
use a single 120-volt fused supply (see Figure 6 for
over-current protection ratings). The installer can
change these units to use a separate circuit for the
pump, if desired. Instructions to make this change are
found in Section 5.1.1 .
Sizes 1750 and 2000 require two 120-volt
fused supplies (see Figure 6 for over- current protection
ratings).