MPO-IQ Installation, Operating, and Service Instructions

50
Figure 32: Cad Cell Location
IX. SYSTEM START-UP (continued)
2. 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.
a. 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.
b. 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.
c. 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 32. 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.
• Close line switch to boiler. If burner starts
and runs beyond safety switch cut-off
time, cell is good. If not, install new cell.
• Close hand valve in oil supply line.
• Failure occurs, device enters Recycle Mode.
Indicator light ashes at ¼ Hz rate
(2 seconds on, 2 seconds off) on R7184 models.
• Device tries to restart system after
approximately 60 seconds.
• After third Recycle Mode trial, safety switch
locks out within safety switch timing indicated
on label and control enters Restricted Mode.
Indicator light ashes at 1 Hz rate (½ second on,
½ second off) on R7184 models. Ignition and
motor stop and oil valves closes.
d. Power Failure Check: After Flame is established,
turn the power off to the control/burner. The burner
should shut down safely. When power is restored a
normal ignition sequence should be started.
WARNING
Cad Cell Jumper must be removed after this check.
K. CHECK HIGH LIMIT
1. Adjust system thermostat(s) to highest setting.
2. Allow burner to run until boiler water temperature
exceeds high limit setting. The burner should shut
down and circulators continue running.
3. Allow the temperature to drop below control setting.
The burner must restart.
4. Boiler installation is not considered complete until this
check has been made.
L. IF CONTROLS MEET REQUIREMENT outlined in
Paragraphs I thru k.
1. Allow boiler to operate for approximately 30 minute,
conrm the boiler and system have no leaks.
2. Reset thermostat(s) at desired setting.
M. IF CONTROLS DO NOT MEET
REQUIREMENTS outlined in Paragraphs I thru k,
replace control and repeat checkout procedures.