I.C.E. 3 OSDs User Manual

Page 6

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Gap must be 1/16” to 3/32” (see Figure 5). Setting can also be checked by cycling the pilot. Ignition must be prompt
and positive. Do not allow careless positioning to cause arc of flame rod; serious relay damage would result.

The spark ignitor on Maxon burners, if ignitor shows deterioration of ignitor points the complete spark ignitor should
be replaced part No. 18075.

8. If pilot tries for ignition, but locks out, the air proving switches (high and low) that are mounted across the profile

plate, should be checked to make sure that the proper amount of air is flowing through the unit. Check to make sure
blowers are running in the proper direction. This can be checked by placing a differential gauge across the profile
plate of the burner section. If the pressure drop is between .30” W.C., and .95” W.C., these switches should be made,
then check pilot to ensure proper flame. Check instruction sheet for flame safeguard system.

Pilot adjustment screw is in the Thermax shut-off valve. When setting, adjust for the best reading, then open pilot set
screw slightly.

a) Main flame supervision: With units that have more than three feet of burner from point or supervision, a second

flame rod will be on the main burner. This switching is done with a time delay relay. See wiring diagram. This can
be disconnected for testing for pilot, or you have to ensure main flame by opening up the firing valve within 15
seconds after pilot solenoid is powered. As supervision will switch from pilot to main flame in that time. Check to
ensure that unit will lockout in the event of main flame failure on low-fire by closing main firing valve.

9. Gradually open firing valve to start main flame. Check for flame over entire burner length. Adjust the pressure

regulator to 4” or 4 ½ ” W.C. pressure or the amount of gas marked on the rating plate.

10. All OSD units may have Maxitrol modulation. Read over the Maxitrol literature for the high fire and low fire setting.

By removing the wire from #2 on the amplifier the unit will stay on low fire and allow you to set the by pass or low
fire setting to ensure that the flame is completely across burner and is between 1” and 1½ ” long (see literature
supplied with unit).

11. To set up high fire you will require spray test resistor 1.10K, dry (cure) test resistor 1.21K. These are attached to the

Maxitrol literature. These resistors should be placed across #3 and #4 of the amplifier on the unit (remove when test
is complete).

a) Check gas pressure switch setting.

High pressure gas switch …………………………………..…… 6” W.C.
Low pressure gas switch ………………………………….……. 2” W.C.

NOTE: The high and low gas pressure switches may be the manual reset type on some units.



The flame supervision should be checked periodically to insure that the controls are operational. With the unit
on full operation and firing, close the main manual firing valve and pilot manual firing valve. This should lock
out the unit.


The units with more than 3 feet of burner from the point of supervision have dual flame rod and a delay timer for
main flame supervision. Closing the main firing valve should lock out the safety relay and the unit should


The main safety valve should be checked for gas tightness by placing a manometer in the manifold between the
safety valve and the manual firing valve (a 1/8” plug is provided for this). If there is a build up of pressure with
the unit locked out and the manual valve closed, the safety valve should be replaced.


The complete gas line and manifold should be checked for gas tightness.

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