Instruction manual
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Pilot Adjustment 
 e pilot burner is actually an isolated main burner that’s 
controlled by a separate pilot valve. Pilot pressure se ings are as 
shown in Table 20.   ese pressures are measured at the pilot pressure 
valve, see Figure 19. Tables 13 and 14 above list the  ring mode 
that is associated with each stage.
To view the pilot without main burner operation, take the following 
steps:
For L225-L400: 
1. Remove the upper front jacket panel. 
2.  Turn o main burner gas  ow by turning the main burner gas 
valve knob to the o position, Figure 18. 
3. Observe the pilot  ame through one of the observation ports 
located at the le and right ends of the unit.
For L600-L2300: 
1. Remove the upper front jacket panel. 
2.  Turn o main burner gas  ow by turning the manual gas valve(s) 
in the control compartment to the o position, see Figure 19. 
3. Observe the pilot  ame through one of the observation ports 
located at the le and right ends of the unit.
Pilot pressures will be set at the factory. However, if it is necessary 
to adjust the pilot pressure to match those in Table 20, take the 
following steps: 
1. Remove the upper front jacket panel. 
2. Remove the 1/8 in plug from the pilot pressure test port and 
connect a 20 in, 508 mm WC manometer to it, see Figure 18. 
3.   Remove the gas pressure regulator cap from the pilot valve. See 
Figure 18 for the location of the regulator and cap. 
4.  Use a 3/32 hex wrench to turn the pressure regulator adjustment 
screw clockwise to increase the pilot pressure and counter 
clockwise to decrease it. 
5. Replace the pressure regulator adjustment screw cap.
Gas Pressure Adjustment 
  e maximum inlet gas pressure listed on the rating 
plate must not be exceeded or damage to the boiler/
water heater may occur voiding the warranty!
  e minimum supply pressure listed on the rating plate is for input 
adjustment.
  e manifold pressures should match those listed in Table 20. 
Pressures should not vary outside these ranges. Each gas valve 
pressure regulator has been preset at the factory. If neccessary, adjust 
the gas pressures to achieve the combustion results show in Table 
21. 
If adjustments are necessary the following steps must be followed:
1.  Remove the 1/8 in plug from the manifold pressure tap valve. 
Connect 20 in, 508 mm WC manometers to it, see Figure 19. 
2.   Remove the regulator adjustment screw cap from the main gas 
valve. 
3.   Rotate the regulator adjustment screw clockwise to increase the 
manifold pressure, counter clockwise to decrease it. 
4. Replace the regulator adjustment screw cap and manual shut 
o valve pressure tap plug.
 Never force the regulator adjustment screw beyond 
the stop limits or damage to the regulator will occur!
PROPANE GAS: Optimum results are obtained when the 
boiler/water heater is operated with the manifold pressure(s) set 
per Table 20. If the manifold pressure is o  by more than 5% adjust 
it according to steps 1 through 4 above.
Air ow Adjustment
1. Remove the upper front jacket panel.
2.   Connect both sides of a manometer to the pressure switch tee, 
Figure 17, going to one of the pressure switches.
3.    With the unit operating at high   re the di erential pressure should 
match those listed in Table 15. Do not change air pressure in 
lower stages.










