Instruction manual

57
Figure 30B: R7284 Oil Primary Terminals,
Display and Function Buttons
10 additional minutes. (press the up arrow
button 10 times). Pressing the down arrow
subtracts a minute from the TFI time (see
Figure 30B).
SECTION XI: SYSTEM START-UP (continued)
> 6100 Ohms Flame loss, burner shuts down
> 9999 Ohms Check for broken cell or wire.
R7284 displays resistance in ohms during
Running Mode.
b. CHECK OIL PRIMARY CONTROL
CAUTION
Due to the potential hazard of line voltage, only a
trained, experienced service technician should
perform the following safety checks.
This control contains no eld-serviceable parts.
DO NOT attempt to take it apart. Replace entire
control if operation is not as described.
i. Preliminary Steps
• Check wiring connections and power
supply.
• Make sure power is on to the controls.
• Make sure limit control is closed.
• Check contacts between ignitor and the
electrodes.
• Check the oil pump pressure.
• Check the piping to the oil tank.
• Check the oil nozzle, oil supply and oil
lter.
ii. Check Safety Features
Safe Start:
• Place a jumper across cad cell terminals.
• Follow procedure to turn on burner.
Burner must not start, indicator light turns
on and control remains in Idle Mode.
• Remove jumper.
iii. Simulate Ignition or Flame Failure:
• Follow procedure to turn on burner.
• Check cad cell resistance. If resistance
is below 1600 OHMS and burner runs
beyond safety cut-out time, cad cell is
good.
• If safety switch shuts down burner and
resistance is above 1600 OHMS, open line
switch to boiler. Access cad cell under
ignitor, clean face of cad cell and see that
cell is securely in socket, see Figure 31.
Check gasket around perimeter of ignitor
lid for proper seal. If gasket is missing
or damaged, replace gasket. Room light
can effect cad cell resistance. Reset safety
switch.
iii. Limited Recycle: This feature limits the
number of recycle trials (for each call
for heat) to a maximum of three trials. If
the ame is lost three times and does not
successfully satisfy a call for heat, the Oil
Primary locks out.
iv. Limited Reset (Restricted Mode): In order
to limit the accumulation of unburned oil in
the combustion area, the control can only be
reset three times. The reset count returns to
zero each time a call for heat is successfully
completed.
v. "T-T" Jumper: All R7284 models have
internal "TT" Congured ON" parameters
set to "ON".
Note: DO NOT change "T-T" Congured
ON" parameters to "OFF" unless wiring
diagram indicates a direct connection from
thermostat and/or tankless heater aquastat
control to the oil burner primary control's
"T-T" terminals. Refer to appropriate
wiring diagram, see Figure 21A, 21B, 22,
23A, 23B, 24A or 24B.
vi. Diagnostic Display: The R7284 has an LCD
display and simply displays lockout and
ame status on it.
vii. Cad Cell Resistance Check: For proper
operation it is important that the cad cell
resistance is below 1600 ohms.
Cad Cell Resistance (ohms) is measured by
the oil primary. The thresholds are:
< 1600 Ohms Normal operation
> 1600 Ohms Service burner soon