Install Instructions

23
e. Check the pilot ame. It must be blue, steady and
envelop the ame sensing rod 3/8” to ½”.
f. If needed, adjust pilot ame by turning the
gas valve pilot adjustment screw clockwise to
decrease or counterclockwise to increase pilot
ame. Always reinstall pilot adjustment screw
cover and tighten securely upon completion to
assure proper gas valve operation.
7. Reconnect MV lead wire to the module upon
satisfactory completion of pilot ame current
measurement.
8. Check the pilot burner operation/ignition sequence
during ignition cycle:
a. Restore boiler power at circuit breaker or fuse
box.
b. Set thermostat to call for heat.
c. Watch ignition sequence at burner.
d. If spark does not stop after pilot lights, replace
ignition module.
e. If main burners do not light or if main burners
light but system locks out, check the module
ground wire and gas control as described in
Figure 20 “ Honeywell Electronic Ignition
Troubleshooting Guide”.
C. 24 Volt Probe Low Water Cutoff. Hydrolevel Model
400 and McDonnell & Miller PS-802-24 Only.
1. Drain boiler to point below Tapping 'K'.
2. Disconnect wire(s) connecting control and probe.
3. Remove control from probe.
4. Unscrew probe from Tapping 'K'. Inspect for scale
and sediment buildup.
5. Remove light deposits with damp cloth soaked with
vinegar.
6. Remove stubborn deposits using diluted phosphoric
acid (H
2
PO
4
) solution, 3 parts water to 1 part
phosphoric acid. Normal operation will occur
with up to 0.2 inch of contamination. If scale or
contamination exceeds 0.2 inches clean probe more
frequently.
7. Clean Tapping 'K' to remove old pipe dope and other
foreign matter.
8. Apply moderate amount of good quality pipe dope
to probe threads, leaving two end threads bare.
Install probe in Tapping 'K'. Mount control on probe.
Attach wire(s) between control and probe.
9. Fill boiler to normal waterline. Add water treatment
as needed.
VIII. Service (continued)
D. Float Low Water Cutoff. McDonnell & Miller 67
Only.
1. Weekly (or more frequently if necessary). Open
blow-off valve to ush sediment chamber. Follow
instructions on Blow-Down Card afxed to Jacket
adjacent to low water cutoff.
2. Annual. Dismantle to extent necessary to remove
obstructions and insure proper function of working
parts.
a. Inspect connecting lines to boiler for
accumulation of mud and scale. Clean as
necessary.
b. Examine wiring for brittle or worn insulation and
clean electrical contact.
c. Inspect solder joints on bellows and oat.
Check oat for evidence of collapse. Check
mercury bulb (where applicable) for mercury
separation or discoloration. Do not attempt
to repair mechanisms in eld. Complete
replacement mechanisms, including gaskets and
instructions, are available from low water cutoff
manufacturer.
3. Five (5) Years or 100,000 switch cycles. Replace
switch and oat mechanisms.
E. Water Feeder and Additional Low Water Cut-Off.
Refer to manufacturer's instructions.
F. Inspect Vent System. See Figure 10.
1. Remove obstructions in vent pipe and chimney.
2. Remove soot accumulations with wire brush and
vacuum.
3. Repair or replace deteriorated vent pipe and vent
accessories.
4. Provide proper support. Repair sags, particularly in
horizontal sections.
5. Repair leaking joints.
G. Inspect Boiler Flue Passages for blockage or soot
accumulation. See Figures 18 and 19.
1. Remove Jacket Vestibule Panel.
2. Remove Drafthood.
3. Inspect ueways for blockage or soot accumulation
through ue outlet of canopy.
4. If cleaning is required, remove canopy from cast
iron heat exchanger. Boiler cement should be
scraped from canopy and heat exchanger.
5. Thoroughly clean ueways with ue brush.
6. Clean heating surface accessible from combustion
chamber using straight handle wire brush.