2
4
1)
Gas pilot ignition failure. Refer to pilot adjustment section and readjust to make certain that the
ignition is instant and that flame signal readings are stable and above minimum values. Use a
manometer or 0 to 10” W.C. gas pressure gauge on pilot test tee to make certain that pressure is
as recommended.
2)
Gas pilot ignition. Verify that there are no cracks in the porcelain and that transformer end and
electrode end plug in connections are tight.
3)
Loose or broken wires. Check all wire nut connections and tighten all terminal screw connections
in panel and elsewhere as appropriate.
4)
Ensure that when main flame lights, the air flow switch is not so critically set as to allow
occasional momentary opening of the air switch contacts.
5)
Occasional low voltage supply. Have local utility correct. Make certain that the burner control
circuit transformer (if supplied) is correct for the voltage being supplied.
6)
Occasional low gas supply pressure. Have utility correct.
7)
Air leak in oil suction line or check valve not holding. Correct as required.
5
5
.
.
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5
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n
n
g
g
S
S
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g
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n
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:
:
G
G
a
a
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s
5.5.1 Burner Motor Runs, but Pilot Does Not Light
1)
Gas supply to burner shut off – make sure all manual gas supply valves are open. Automatic
high pressure valve at meter such as Sentry type tripped shut due to high gas pressure – reset
valve and correct cause for trip out.
2)
Pilot solenoid valve not opening – listen and feel for valve actuation. Solenoid valve not being
powered – check electrical circuitry. Replace coil or entire valve if coil is burned out.
3)
Defective gas pilot regulator – replace.
4)
Gas pressure too high or too low at pilot. Readjust as required.
5)
Defective ignition transformer – replace. Incorrect ignition electrode settings – refer to gas pilot
adjustments for correct settings.
6)
Defective flame safeguard control or plug in purge timing card. Replace as required.
7)
Air flow switch not making circuit – check out electrically and correct pressure adjustment on
switch, if required. Defective air flow switch – replace. Air switch negative pressure sensing tube
out of position – reposition as necessary.
5.5.2 Burner Motor Runs and Pilot Lights, but Main Gas Flame Is Not Established
1)
Main shutoff or test cock closed. Check to make certain fully open.
2)
Pilot flame signal reading too low to pull in flame safeguard relay. Refer to gas pilot settings
section and readjust as required.
3)
Defective automatic main or auxiliary gas shut off valves. Check electrical circuitry to valves.
Replace valves or correct circuitry as required.
4)
Defective flame safeguard control or plug in amplifier. Check and replace as required.
5)
Butterfly valve set incorrectly on modulating burner. Readjust as required.
6)
Main gas pressure regulator atmospheric vent line obstructed. Correct.
7)
Defective main gas pressure regulator – replace. Misadjusted main gas pressure regulator –
readjust to meet required operational values.
5.5.3 Carbon Monoxide Readings on Gas Firing
1)
Flame impingement on cold heat transfer surfaces caused by excessive firing rate. Reduce firing
rate to correct input volume.
2)
Flame impingement on cold combustion chamber surfaces due to undersized combustion
chamber. Refer to chamber size charts and/or contact factory for additional information.
3)
Incorrect gas/air ratios. Readjust burner to correct CO
2
/ O
2
levels, reducing CO formation to
appropriate level.
4)
FGR rate too high. Reduce FGR to the minimum required to obtain <9 ppm NOx.
5.5.4 Gas High Fire Input Cannot Be Achieved
Содержание UCM-1000
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