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3.
The heaters should be wired exactly as shown in
the wiring diagram.
IMPORTANT NOTE:
The pool filter pump
and heater must be electrically interlocked so the
heater cannot come on unless the pump is running
and there is full flow in the filter piping where the
heater is connected. If the pool filter pump operation
is intermittent the heater must be shut off prior to
pump shutdown. See paragraph heading Auxiliary
Time Clock Wiring below. If the backwash operation
is manual the heater must be shut off manually during
backwashing.
Auxiliary Time Clock Wiring:
If a time clock is used to control the filter pump
operation, a separate switch or relay must be used to
shut off the heater at least
15 minutes before
the filter
pump is shut off. Wire the switch or relay (often called
the Fireman Switch) to the terminals shown in the
wiring diagram as “Field Interlock.”
4. All field installed electrical safety devices and
all field installed controllers (valve end switches,
draft switches, relays, timers) can be connected
to the heater control to the terminals shown in the
wiring diagram designated “Field Interlock.”
5.
Field location of the temperature sensor is
described in Section 2.8.
Where the heater is installed with a draft fan
refer to the fan manufacturer's wiring diagram. The
draft switch should be wired across the field interlock
terminals in the heater control panel.
2.6 General Piping Instructions
In addition to the bypass valve “A” and outlet
valve “B” shown in Figure 10, an inlet valve “C”
should be provided so that the heater can be readily
isolated for service. All valves should be butterfly or
ball style, not gate valves. For spas application see
Section 3.9.
Since heater outlet temperatures can reach
150°F (66°C) in some cases, copper or CPVC are
recommended materials for heater connection piping.
PVC material may be used for the inlet valve and the
piping upstream of it.
When pipe, fittings, grids or any other element
of the filter system are made of plastic materials, they
may be damaged by the momentary "back siphoning"
of hot water from the heater when the filter pump stops
running.
The pressure relief valve installed in the tapped
opening provided in the outlet header (see Figure 9),
must be piped, but not connected, 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.
Where no special setting of the relief valve is ordered,
the factory will furnish a 75 psi setting.
The 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 the drain line. Precautions must be taken to
avoid contact with hot water and water damage.
2.7 Heater By-Pass Piping
All models/sizes of this pool heater must be
installed with bypass piping. Please use Figure 10 as
your guide to plumb the bypass. For spas see Section
3.9.
If the distance from the pool heater to the pool
loop piping is greater than 15' please contact the
Service Department for assistance (see back page for
phone and fax numbers).
All models are supplied with integral pumps,
These pumps are sized for the pressure drop through
the heat exchanger, 30' of piping, and through the
bypass piping as shown in Figure 10.
Any deviations from the arrangement shown
may reduce flow, hinder performance, and will void
the warranty.
2½ inch NPT piping is shown, however, models
500I-1430I and models 500E-1010E may be installed
using 2 inch NPT piping.
All models must be installed in the primary/
secondary arrangement shown. The heater loop piping
must tee into the filter loop piping with the inlet
and outlet connection spaced a maximum of 4 pipe
diameters apart (see Figure 10).
To insure that pool inlet water does not exceed
104°F, the filter pump loop must circulate at the
minimum flow rates shown in Table 4.
The outlet valve “B” and the bypass valve “A”
must have a provision for locking the handles in place
(or removing them) after the temperature rise and inlet
temperature adjustments have been made.
Figure 9 - Pressure Relief Valve Location
MightyTherm Pool Heater
