Heat Transfer MODCON VWH 300 LP Installation & Maintenance page 44

PART 7: GAS PIPING
DETAIL A
SCALE 2:1.5
GAS PRESSURE
SWITCH BLOCK
GAS SHUT OFF
VALVE
GAS OUTLET
DETAIL B
SCALE 2:1.5
Fig. 7-4
43
GAS-FIRED HOT WATER SUPPLY BOILER
(CONTINUED)
MOD CON 850 GAS VALVE
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
GAS SUPPLY OR TO THE (-) TO DECREASE GAS SUPPLY.
THIS ADJUSTMENT COULD AFFECT CO/CO% LEVELS.
MAKE SURE THE LEVELS CORRESPOND TO THE CHART IN THE
COMBUSTION SETTINGS SECTION (FIG. 10-1)
A
GAS OUTLET
PRESSURE
TAP
OFFSET ADJUSTMENT
CAUTION: DO NOT REMOVE THIS SCREW OR ATTEMPT TO
MAKE ANY ADJUSTMENT TO THIS SCREW WITHOUT USING
A COMBUSTION ANALYZER.
INTERMEDIATE
PRESSURE TAP
B
GAS INLET
PRESSURE
TAP
Boiler Manual
GAS VALVE
GAS PRESSURE
SWITCH BLOCK
GAS INLET
LP-205-O Rev. 5/27/08