Data Sheet for Product

QBM81-… Differential Pressure Switch Technical Instructions
Document Number CA1N1552E-P25
November 24, 2003
Accessories
For difficult conditions or cases where high-precision measurements are required,
two other kits are available:
FK-PZ1 Set of two duct probes (nickel-plated iron) with rubber grommet
FK-PZ2 Set of two duct probes (aluminum) with aluminum mounting rosettes and
four mounting screws
Mounting Notes
Mounting instructions are enclosed with the pressure switch.
NOTE: Mounting positions other than vertical affect the cut-in pressure. See
Commissioning Notes.
The pressure switch is suitable for mounting on air ducts or walls. The recommended
orientation is vertical, but any orientation is acceptable. The pressure connection tubes
can be of any length, but the response time will increase if they are longer than 6.6 feet
(2 meters).
The pressure switch should be mounted so that it is above the pressure connection
points. To prevent the accumulation of condensation, the tubing must be routed so that
there is a gradual incline from the pressure connection points to the pressure switch (no
looping).
Commissioning
Notes
The required setpoint can be selected on the setpoint knob located under the cover.
See Dimensions, Item 5.
NOTE: The setpoint scale provided with the unit is metric.
The pressure switch is factory-calibrated in the vertical position. If installed horizontally,
this will affect the switching point as follows:
•
•
With cover facing upwards: Switching point is 0.044" WC higher than scale.
With cover facing downwards: Switching point is 0.044" WC lower than scale.
Specifications
Electrical Interface
Type of switch Single-pole change-over, multi-layer
contact
Contact rating 24 Vac/dc, >0.01 A
250 Vac
Maximum 5 A resistive
Maximum 3 A inductive, cos ϕ >0.6
(0.8 A starting current sixfold,
cos ϕ > 0.6
Operating voltage Maximum 250 Vac
Switching differential (∆p)* Adjustable
Reset Automatic
Service life >1,000,000 switching operations
Product Data Measuring range See Product Numbers
Repeatability
Range 0.08 to 1.20 in WC <± 0.10 in. WC
Range 0.20 to 4.00 in WC <± 0.02 in. WC
Maximum overload on one side 20.07 in. WC
Admissible media Air and non-corrosive gases
Siemens Building Technologies, Inc. Page 3