Heat Transfer MODCON VWH 300 LP Installation & Maintenance page 43

PART 7: GAS PIPING
GAS PRESSURE
SWITCH BLOCK
GAS OUTLET
PRESSURE TAP
GAS OUTLET
GAS VALVE
GAS INLET
PRESSURE TAP
GAS SHUT-OFF
VALVE
Fig. 7-3
GAS-FIRED HOT WATER SUPPLY BOILER
(CONTINUED)
MOD CON 500 GAS VALVE
SCALE 2 : 3
A
OFFSET ADJUSTMENT
CAUTION: DO NOT REMOVE THIS SCREW
OR ATTEMPT TO MAKE ANY ADJUSTMENT TO
THIS SCREW WITHOUT A COMBUSTION ANALYZER
GAS PRESSURE
SWITCH BLOCK
GAS INLET
THROTTLE ADJUSTER
NOTE: IF FOR ANY REASON THE THROTTLE
NEEDS TO BE ADJUSTED, IT IS VERY IMPORTANT
THAT A "COMBUSTION ANALYZER" BE USED TO
ENSURE SAFE AND PROPER OPERATION. TURN
THE ADJUSTER TO THE (+) TO INCREASE THE GAS
OR (-) TO DECREASE THE GAS SUPPLY. THIS
ADJUSTMENT COULD AFFECT CO/CO% LEVELS.
MAKE SURE THE LEVELS CORRESPOND TO THE
CHART IN COMBUSTION SETTINGS.
(FIG. 10-1)
DETAIL A
Boiler Manual
LP-205-BB Rev. 6/3/08
42