Honeywell SV2 Series User Manual page 83

SV2 SERIES SAFETY SHUT-OFF VALVES USER MANUAL
Part Number Description
FARMODFILTER-000B Field replacement pre-filter assembly for premix valves fuel/air ratio module. Bulk pack of 12.
Table 22. Air pre-filter replacement part information.
NOTES:
• Due to the variety of possible appliance configurations, the fittings and tubing must be ordered separately. Refer to Table 17
for information.
• The customer must furnish an appropriate filter mounting bracket for their chosen location.
Fig. 41: Pre-Filter dimensional and mounting information.
SV2 Series Fuel/Air Valve Theory of Operation
Introduction
Fuel/air ratio control within the SV2 Series Premix valves is accomplished with a Fuel/Air Ratio Module and a stepper motor
driven Fuel Control Valve (throttle) embedded in the main valve body.
The Fuel/Air Ratio Module (FARMOD) is equipped with 3 embedded mass flow sensors, which provide accurate differential
air and gas pressure measurement data to the SV2 Series main control. During commissioning of the appliance / burner,
amplification values (the ratio between dPgas and dPair) are set at various burner loads to meet specific lambda / O2 (CO2)
requirements of the appliance
After commissioning is complete and the appliance is running, the Fuel Control Valve is controlled/modulated by a comparison
of the actual sensor readings against the setpoint which is derived from the stored amplification settings to accurately control
the lambda / O2 (CO2) behavior against the burner load. The ability of the SV2 Series Fuel/Air Ratio control system to store up
to 24 burner load-dependable amplification values allows for maximal flexibility in the optimization of the appliance/burner
combustion process.
During the burner start-up sequence (pre-purge) and burner operation, the SV2 Series Fuel/Air Ratio control system ensures
the presence of sufficient air to assure a safe combustion process. Software algorithms are embedded in the SV2 Series main
control to detect an un-configured Fuel/Air control system to prevent the appliance from operation. Further, the SV2 Series
Fuel/Air Ratio control system is equipped with safeguards to assure reliable operation of the burner.
The SV2 Series Fuel/Air control system fulfills the requirements of all applicable European and North American standards. Refer
to the Valve Specifications section of this document for an overview of the applicable standards.
The SV2 Series Fuel/Air Ratio control system is suitable for Premix appliance applications.
FARMOD Measuring Principle
Fig. 42 shows the FARMOD sensor orientations and pulse line connections to a Premix burner with a mixing unit.
SV2 Series Safety Shut-off Valves 83
V2F, V2V