HydroTherm KN-2 - Page 39

P/N 42-9450 8/08 Copyright 2008 Hydrotherm
Page 39 KN INSTALLATION AND OPERATION INSTRUCTIONS
Figure 30 Removing boiler jacket top
Figure 31 Gas valve adjustments
Starting the boiler (continued)
When is low  re adjustment required?
Adjust the gas valve low- re se ing ONLY if the  ame is unacceptable,
the CO2, O2 or CO are out of acceptable range or you are changing
fuels. You will need to remove the boiler jacket top and adjust the gas
valve low- re se ing as described below.
The boiler jacket top must be removed when it is necessary to access the gas
valve low- re adjustment screw or other interior components, such as the blower
motor. Use the procedure below.
Removing the boiler jacket top
See Figure 30.
Remove the three thumb screws securing the  lter access plate.
Remove and set aside the  lter access cover and gasket.
Pull back on the  lter clamp and remove the  lter.
Hold the  lter clamp back as in Figure 30.
Squeeze the conical grommet sides and maneuver the grommet out of the opening
in the jacket top.
If there is no air pipe a ached to the air inlet, leave the air inlet plate in place.
If air is piped to the air inlet plate, remove the air inlet plate and gasket by removing
the four screws that secure it to the jacket top. Make sure the air piping is properly
supported.
Remove the seven Phillips-head screws securing the jacket top to the jacket sides.
Li o the jacket top. (Leave the wire harnesses connected.)
Move the insulation aside if necessary.
Adjusting the low- re setting
DO NOT adjust the low- re se ing unless low- re  ame or combustion
are unacceptable.
See Figure 31 for the location of the gas valve low- re adjustment. Use a 2-mm
hex wrench.
When adjusting the low- re se ing, make changes in half-turn increments. Allow
the  ame to stabilize before adjusting each time. (Reduce gas input if the  ame or
burner appears red.)
If CO
2
is too HIGH (O
2
too low):
REDUCE gas by turning the adjustment COUNTERCLOCKWISE (one
half turn at a time). Recheck the analyzer and  ame a er each half turn.
4. If CO
2
is too LOW (O
2
too high):
INCREASE gas by turning the adjustment CLOCKWISE (one half turn at a
time). Recheck the analyzer and  ame a er each half turn.
Replace the boiler jacket top
To replace the jacket top, reverse this order above. Make sure insulation is in place.
Slide the conical grommet over the blower inlet  en seat the grommet ring into
the hole in the jacket top.
Rea ach the air inlet plate if it was removed. Inspect the air piping to make sure it
was not displaced.
Pull the air  lter clamp back. Replace the  lter, gasket and access cover. Secure with
the three thumbscrews. Replace the gas valve cover plate if removed.
Remove the low- re jumper from the connection board. Replace the electrical
panel cover.
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