Install Instructions

22
PILOT BURNER USED ON I.I.D. SYSTEMS
FIGURE 14
PROTECTOR SWITCH
(COIL HIGH LIMIT - ALL HEATERS)
If the protector switch, g 2, should shut off unit, check for the
following conditions:
1. No water in heater.
2. Restricted water ow through the heater.
3. Excessive liming.
4. Improper wiring (automatic gas shutoff control acting as primary
control).
5. Pump failure.
After correcting failure condition, remove the protector switch
cover and depress reset button. Button will not reset until
water temperature in heater coil is down to 200
0
F. Restart
heater, following the “OPERATING INSTRUCTIONS FOR I.I.D.
MODELS” , PAGE 19.
PROTECTOR SWITCH CONTINUITY TEST
Do not depress the protector switch reset button prior to testing.
The leads from the switch are removed at the point farthest from
the switch.
Attach the leads from a test ashlight to the switch leads.
Check with an Ohm meter.
TANK TEMPERATURE CONTROL
The tank temperature control is the primary operating control of
the system. The sensing element is mounted on the hot water
storage tank. A change of temperature lower than the control
setting will cause the element to activate the electrical switch and
start the heater.
AUTOMATIC GAS SHUTOFF CONTROL
The automatic gas shutoff control, g. 1, is an automatic device
which is wired in series with the gas valve and intermittent ignition
control module.
The control settings are xed at 195
0
F (90.5°C) cut-out and
190
0
F (87.7°C) cut-in. Reduced water ow due to lime scale
accumulation is one cause of frequent automatic gas shutoff
control operations. Refer to “PREVENTIVE MAINTENANCE”
section for deliming instructions. If this non-adjustable control is
out of calibration, replace control.
THERMAL BALANCER
Figure 15 shows the internal wiring of the thermal balancer. The
device may be tested after disconnecting the four leads from their
respective terminals on the unit.
1. Apply a test light to the yellow and red leads:
• The lamp should light as the contact in this circuit is normally
closed when the resistor is cool.
2. Apply the light to the black and yellow leads.
• The lamp should not light as the contact in this circuit is
normally open when the resistor is cool.
3. Remove the test light.
4. Apply 120 volts to the white and red leads which power the
1900 ohm resistor.
• After warming period, the contacts of the thermal balancer
should change position.
5. Remove the 120 volt power source.
6. Apply the test light as described in steps 1 and 2.
• While the resistor is still warm, the lamp indications should
be the opposite as described above. If this is not the case,
replace the thermal balancer.
THERMAL BALANCER SCHEMATIC DIAGRAM
FIGURE 15
INPECTING THE HEAT EXCHANGER AND
VENTING SYSTEM
Every 6 months, inspect the venting system (including the chimney)
for blockages which will retard free draft and points of ue gas
leakage. Remove any obstructions and replace any damaged or
deteriorated vent pipe.
Check the heat exchanger to be sure it is not blocked by dirt or
soot. It is not sufcient to only look through the ue outlet with
the draft hood removed. Examination should also be made using
a mirror and light through the burner opening, viewing the entire
bottom area of the exchanger.
Qualied servicers should follow this procedure when the heater’s
external heating surfaces need cleaning.