Try to clean the thermopile, it should be free of dirt/ soot so heat from pilot flame could be sensed better. Thermopiles generate small amount of voltage when heated properly, the voltage it creates is used in energizing gas valve solenoid coils. Check also if the hi limit is good, small amount of voltage thermopile generates pass through hi limit terminals.
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Try to clean the thermopile, it should be free of dirt/ soot so heat from pilot flame could be sensed better. Thermopiles generate small amount of voltage when heated properly, the voltage it creates is used in energizing gas valve solenoid coils.
Check also if the hi limit is good, small amount of voltage thermopile generates pass through hi limit terminals.