Patterson-Kelley MOD-04 ユーザーズマニュアル

 21 

See rating plate for the minimum and maximum gas 
pressure of the boiler.  Each boiler is furnished with 
two plugged taps in the gas manifold for test gauge 
connections.  One tap is located at the main gas 
cock for measuring the gas supply pressure (1/4” 
IPS).  The supply pressure during main burner op-
eration must be greater than the minimum indicated 
on the rating plate.  The second tap is located down-
stream from the last main gas control in the union 
elbow where the gas line enters the back of the 
cabinet and is for measuring the manifold gas pres-
sure (1/8” I.P.S.) 

 

 

 

 

To adjust the gas pressure, remove the cover plate 
from the air / gas ratio control valve.  Set the boiler 
at High fire as described in the boiler operation sec-
tion of the manual.  The High fire gas pressure is 
adjusted with the lower screw of the air / gas ratio 
control vale.  Using a combustion analyzer, adjust 
the oxygen reading between 6.5% and 7.5%.  Set the 
boiler at Low fire as described in the boiler opera-
tion section of the manual.  For initial adjustment 
the cabinet pressure should be the same as shown on 
the “Factory Firetest” label.  The Low fire gas pres-
sure is adjusted with the upper screw of the air / gas 
ratio control valve.  Using combustion measurement 
equipment, adjust the oxygen reading between 6.5% 
and 7.5%. 

Run the firing rate up and down through the com-
plete firing range and verify that the oxygen read-
ings are within the proper range. 

 
 

Low-fire Adjustment 

High fire Adjustment 

 
 

  Start boiler in test mode 

 
 

  Adjust start pressure with orange cam 1.0” – 1.2” H2O cabinet air 

 
 

  Adjust pilot gas for good pilot – See factory run out label 

 
 

  Start boiler and measure combustion O2 between 6.0 – 8.0 

 
 

  Ramp to high fire adjust cabinet air to nameplate with red cam. Combustion O2 between 7.0 – 7.5. 

 
 

  Ramp to low fire 0.3” adjust cabinet air with blue cam 

 
 

  Check high fire and low fire again