P/N S794
Rev. B 6-23-08
3 4
SAFETY CONTROLS
AIR FLOW SWITCH (AFS)
The air flow switch, (see
Figure 30
), is a safety device used to insure that the
combustion air blower (fan) is operating and has been designed to monitor the
vacuum (negative) pressure within the blower housing. The air flow switch is
factory set and is connected upstream of the ignition module. The ignition module
does not operate unless the air pressure switch and all safety switches are
closed.
WATER PRESSURE SWITCH
WARNING
Hazardous pressure. Do not bypass the Water Pressure Switch or render
it inoperable.
The water pressure switch, (see
Figure 31
). If the water flow is restricted, the
water pressure switch may prevent the burner from firing and cause the “Service
System” light to go on. If the light remains on after the filter has been serviced,
have a qualified service technician check the system.
For deck-level heater installations, the Water Pressure Switch is factory set at
3.00 psi (20.6 kPa).
NOTE: See, Below Pool Level Installation instructions on
page 12
. If the pressure switch is one feet (.3M) below or above the pool
water level, reset the switch so that it is open when the pump is off and closed
when the pump is running. Turn the star-wheel on the switch clockwise ( )
to raise setting (heater below the pool) and counterclockwise ( ) to lower
the setting (heater above the pool – see
Figure 32
. Test the switch after resetting.
NOTICE:
When the heater is mounted more than five feet (1.5M) above or
four feet (1.2M) below the deck level, a Pressure Switch is no longer adequate.
A Flow Switch must be installed instead.
NOTICE:
Heater operation with incorrect
Pressure Switch setting may cause operation
with no water flow. Operation of the heater
without sufficient water flow may severely
damage it.
HIGH LIMITS
A “High Limit”, is a safety device that opens
the electrical circuit and shuts off the heater
based on a water temperature set point within
the “High Limit Device”. The Max-E-Therm
series of heaters contains two (2) high limit
devices which are located on the main inlet /
outlet header.
Air Flow Switch
Section 3. Operation
Figure 31.
Water
Pressure
Switch
Star Wheel
A reference scale is on
the back of pressure switch
Turn star wheel
clockwise
to
raise
pressure set point if pressure switch is more
than 4 feet (1.2M) below water level
Turn star wheel
counterclockwise
to lower
pressure set point if pressure switch is more
than 5 feet (1.5M) above water level
Figure 32.
Figure 30.
