Equipment Tuning Procedure1
                     for Forced Draft Fired Equipment

Nothing in this Equipment Tuning Procedure shall be construed to require
any act or omission that would result in unsafe conditions or would be
in violation of any regulation or requirement established by Factory
Mutual, Industrial Risk Insurors, National Fire Prevention Association,
the California Department of Industrial Relations (Occupational Safety
and Health Division). the Federal Occupational Safety and Health
Administration, or other relevant regulations and requirements.

1.       Operate the unit at the firing rate most typical of normal
         operation.  If the unit experiences significant load variations
         during normal operation, operate it at its average firing rate.

2.       At this firing rate, record stack gas temperature, oxygen
         concentration, and CO concentration (for gaseous fuels) or smoke-
         spot number2 (for liquid fuels), and observe flame conditions after
         unit operation stabilizes at the firing rate selected.  If the
         excess oxygen in the stack gas is at the lower end of the range of
         typical minimum values3, and if the CO emissions are low and there
         is not smoke, the unit is probably operating at near optimum
         efficiency - at this particular firing rate.  However, complete the
         remaining portion of this procedure to determine whether still
         lower oxygen levels are practical.

3.       Increase combustion air flow to the furnace until stack gas oxygen
         levels increase by one to two percent over the level measured in
         Step 2.  As in Step 2, record the stack gas temperature, CO
         concentration (for gaseous fuels) or smoke-spot number (for liquid
         fuels), and observe flame conditions for these higher oxygen levels
         after boiler operation stabilizes.

4.       Decrease combustion air flow until the stack gas oxygen
         concentration is at the level measured in Step 2.  From this level
         gradually reduce the combustion air flow, in small increments. 
         After each increment, record the stack gas temperature, oxygen
         concentration, CO concentration (for gaseous fuels) and smoke-spot
         number (for liquid fuels).  Also observe the flame and record any
         changes in its condition.

5.       Continue to reduce combustion air flow stepwise, until one of these
         limits in reached:

         a.   Unacceptable flame conditions - such as flame impingement on
              furnace walls or burner parts, excessive flame carryover, or
              flame instability.
         b.   Stack gas CO concentrations greater than 400 ppm.
         c.   Smoking at the stack.

         d.   Equipment-related limitations - such as low windbox/furnace
              pressure differential, built in air-flow limits, etc.

6.       Develop an 02/CO curve (for gaseous fuels) or 02/smoke curve (for
         liquid fuels) similar to those shown in Figures 1 and 2 using the
         excess oxygen and CO or smoke-spot number data obtained at each
         combustion air flow setting.

7.       From the curves prepared in Step 6, find the stack gas oxygen
         levels where the CO emissions or smoke-spot number equal the
         following values:

         Fuel           Measurement         Value

         Gaseous        CO Emissions        400 ppm

         #1 & #2 oils   smoke-spot number   number 1

         #4 oil         smoke-spot number   number 2

         #5 oil         smoke-spot number   number 3

         Other oils     smoke-spot number   number 4

         The above conditions are referred to as CO or smoke threshold, or
         as the minimum excess oxygen level.

         Compare this minimum value of excess oxygen to the expected value
         provided by the combustion unit manufacturer.  If the minimum level
         found is substantially higher than the value provided by the
         combustion unit manufacturer, burner adjustments can probably be
         made to improve fuel and air mixing, thereby allowing operation
         with less air.

8.       Add 0.5 to 2.0 percent to the minimum excess oxygen level found in
         Step 7 and reset burner controls to operate automatically at this
         higher stack gas oxygen level.  This margin above the minimum
         oxygen level accounts for fuel variations, variations in
         atmospheric conditions, load changes, and nonrepeatability or play
         in automatic controls.

9.       If the load of the combustion unit varies significantly during
         normal operation, repeat Steps 1-8 for firing rates that represent
         the upper and lower limits of the range of the load.  Because
         control adjustments at one firing rate may affect conditions at
         other firing rates, it may not be possible to establish the optimum
         excess oxygen level at all firing rates.  If this is the case,
         choose the burner control settings that give best performance over
         the range of firing rates.  If one firing rate predominates,
         settings should optimize conditions at that rate.

10.      Verify that the new settings can accommodate the sudden changes
         that may occur in daily operation without adverse effects.  Do this
         by increasing and decreasing load rapidly while observing the flame
         and stack.  If any of the conditions in Step 5 result, reset the
         combustion controls to provide a slightly higher level of excess
         oxygen at the affect firing rates.  Next, verify these new settings
         in a similar fashion.  Then make sure that the final control
         settings are recorded at steady-state operating conditions for
         future reference.
                                      Figure 1

                           Oxygen/CO Characteristic Curve

                                      Figure 2

                          Oxygen/Smoke Characteristic Curve