Bryan Boilers & 300 ユーザーズマニュアル

ページ / 81
 
Date:  
8-4-2010 
 
Revision: 0 
 
Form:  
2396
 
2.3 B
OILER 
C
OMMISSIONING
 
NOTE: 
All of the installation instructions found in section 
1 must be completed before commissioning the 
boiler.  
 
WARNING: 
The following procedures must be 
followed carefully before putting the 
boiler in operation.  Failure to do so 
will present severe hazards to 
equipment, operating personnel and 
building occupants.
 
2.3.1 M
ODULATION
 
 
Figure 39 Air / Gas Ratio Tappings 
 
Modulation on the Triple-flex boiler is 
accomplished with air / gas ratio control.  The 
system consists of two major components, a 
blower (Figure 10 item 6) and a regulating gas 
valve (Figure 7 item 3).  The blower is variable 
speed and provides combustion air to the 
burner.  The blower rpm is controlled by a PWM 
(pulse width modulation) signal.  The PWM 
signal increases or decreases as the load 
increases or decreases in the hydronic system.  
The regulating gas valve is a 1:1 differential 
pressure air / gas ratio controller.  This means 
that the control adjusts the same pressure 
difference on the gas side as it senses on the 
airside.  The airside pressure is the difference 
between the pressure in the burner housing and 
the pressure downstream of the furnace section.  
The gas side pressure is the difference between 
the pressure upstream and downstream of the 
gas limiting orifice valve.  For the locations of the 
+/- gas and air connections see (Figure 39).  Air 
to gas ratios are adjusted with the gas limiting 
orifice valve (Figure 7 item 26). 
 
During the burner pre-purge period, when the 
gas valve is closed, only the air pressure 
difference acts on the regulator causing the air 
diaphragm to move to the left and closes the 
regulating hydraulic bypass valve.  When the 
actuator is powered, the gas valve begins to 
open.  The downstream gas pressure difference 
immediately begins to increase until the gas 
pressure difference is in balance with the air 
pressure difference. 
2.3.2 T
EST 
S
ETUP
 
Connect a u-tube manometer to the gas 
manifold pressure tapping (Figure 7 item 12). 
 
Connect a 0 – 5 psi gauge in the port provided in 
the low gas pressure switch connection (Figure 
7 item 28). 
 
Connect a u-tube manometer to the pilot gas 
pressure port provided (Figure 7 item 14). 
 
A suitable combustion analyzer shall be used for 
measuring O2, CO, and Nox levels.  The 
analyzer probe should be inserted in the stack 
above the boiler outlet and before any draft 
controls.  Calibration is required for the Nox and 
CO cells at the time of commissioning. 
2.3.3 P
RE 
C
HECKS 
A
ND 
S
ETUP
 
Close the manual gas cock (Figure 7 item 4). 
35