Honeywell SV2 Series User Manual page 59

Table 12. Pressure Module Placement.
Valve Model Description
V2F On/off
Fuel/air Premix with
V2V
4
mixing unit
1. Pressure module must be mounted on the same side as the electronics enclosure.
2. During initial valve setup using the HMI or PC Tools, any functions using the Pressure Module must be setup before the valve will be operational.
3. Refer to Fig. 16 and Fig. 18 for pressure access locations and pressure ports.
4. The Pressure Module cannot be used at this time for low gas pressure, high gas pressure or VPS. It is suggested to use the C6907 pressure switches for those
functions instead. Refer to Table 12.
WARNING!
Explosion or Fire Hazard
Can cause severe injury, death, or property damage.
• Turn off gas supply before starting installation
• Disconnect power supplies before beginning
installation
• More than one disconnect can be involved
Theory of Operation
Pressure measurement with the Pressure Module is accomplished via 3 embedded sensors, which cover the associated range
for low gas and high gas pressure. There are two high and one low pressure sensor in each Pressure Module to both extend
the pressure range and maintain accuracy over the required pressure and temperature range. Refer to
Pressure Module models and pressure ranges. At low pressures, the low pressure sensor reading is used while at high pressures,
only the high pressure sensor readings are used. In the middle all three pressure sensor readings are used for a smooth transition.
Depending on the valve model and Pressure Module mounting location, both low gas and high gas pressure measurements can
be made with the Pressure Module when mounted to a single location. Pressure is only actively measured when both valve seats
are powered and non-zero flow is established, which is accomplished via embedded software algorithms. As a result, any low gas
pressure condition that occurs while the valve is de-energized is ignored and allows the low gas pressure limit to be located in
the intermediate position between the two valve seats or after the two valve seats. The high gas pressure limit is measured from
the same location when both valve seats are powered with non-zero flow. As a result, there is no potential for a high gas pressure
limit fault if there is a leaking upstream pressure regulator in the off-cycle.
Since the SV2 Series Pressure Module pressure measurement is performance based, pressure measurements can be taken
via the valve middle (M) or outlet (O) ports. Previous pressure switch technology dictated that the low gas pressure switch
shall be located upstream of the first safety shut-off seat, a prescriptive based approach. The prescriptive based approach for
the high gas pressure switch indicated it shall be located downstream of the service gas pressure regulator or may be located
downstream of all main burner gas supply controls.
In addition to low gas pressure and high gas pressure measurements, the Pressure Module can be used for VPS (valve proving
sequence) pressure measurements when mounted to a (M) Middle / mid-valve seat pressure access port. Refer to
applicable pressure sensing functions and mounting locations.
Software algorithms are embedded in the SV2 Series valves to identify not only low and high gas pressure limit faults and VPS
test failures, but also when a Pressure Module is un-configured, if there is a reading fault with the Pressure Module, if a pressure
limit setting is unusable based on the pressure range of the selected Pressure Module and if the selected Pressure Module is
incompatible with the applied valve pressure.
For premix valves, those that start with the V2V prefix, at this time the Pressure Module cannot be used for the low gas pressure
limit, high gas pressure limit, VPS or leak detection due to the low pressures present at the mid-point between the two valve
seats and at the valve outlet while the combustion fan is running. Instead, the C6907 pressure switches can be used for those
functions. The C6097 pressure switches can be used for single-function operation including low gas pressure limit, high gas
limit function and VPS. Refer to the
and mounting locations and
SV2 Series Safety Shut-off Valves
V2F, V2V
Low gas pressure, High gas pressure, VPS, Leak
Low gas pressure, High gas pressure
C6097 Pressure Switches
Table 10.
SV2 SERIES SAFETY SHUT-OFF VALVES USER MANUAL
Functions
1, 2
detection
-
WARNING!
Electric Shock Hazard
Can cause serious personal injury or death.
• Disconnect power supply before beginning
installation
• More than one disconnection can be involved
section of this document for available functions, mounting styles
59
Pressure Pressure Port
Access to Open
Location
3
A/C on V1 Middle (M)
B/D on V2 Middle (M)
B/D on V2 Outlet (O)
- -
Table 11 for applicable
Table 12
3
for