User Manual

ManualsBrandsSiemens ManualsSensors Dew PointDewpoint sensor and signal converter FA-H3, FU-IH3

Siemens Building Technologies CA1N1879E / 11.1998

Landis & Staefa Division 1/4

879

Dewpoint sensor

Signal converter

FA-H3

FU-IH3

FA-H3

FU-IH3

The FA-H3 dewpoint sensor is used to detect condensation on chilled ceilings.

•

For direct connection to the PRONTO PRT-H3 individual room controller

•

For connection to other controllers with the FU-IH3 signal converter

The FA-H3 dewpoint sensor is used to prevent condensation forming on the surfaces of

chilled ceiling installations. At the onset of condensation, the sensor operates as a high-

limit device providing an override signal via the controller to switch off the chilled water

supply.

Important : Dewpoint control of the central plant is recommended in addition

to the local control provided by the FA-H3 sensor.

For optimum performance of the chilled ceiling system, dewpoint control of the central

plant is recommended in addition to local control. In this way, the flow temperature for

the entire building or for a section of the building will be controlled in accordance with

the dewpoint temperature in a reference room, or in the return or outside air.

The FA-H3 dewpoint sensor incorporates a sensor element whose electrical resistance

is affected by humidity. This element changes markedly when exposed to condensation.

The PRT-H3 controller evaluates the change in resistance directly.

If other controllers are used, the FU-IH3 signal converter is necessary.

The FA-H3 dewpoint sensor and the FU-IH3 signal converter, if required, must be

ordered separately. A cable tie is supplied with the sensor.

When placing an order, please specify the quantity, product description and type code.

Example:

1 dewpoint sensor FA-H3

and

1 signal converter FU-IH3

The FU-IH3 signal converter should be used for PRONTO IRC controller types PRRA,

PRRB, PRU..., PRFB-A or PRFB-V, and PRT/F or for other controllers.

The FU-IH3 signal converter converts the change in resistance into an ON/OFF signal

before transmitting it to the controller.

The FA-H3 dewpoint sensor comprises the following parts:

– Plastic housing with built-in sensor element and connecting cable

– Cable tie for fixing the sensor to a pipe.

Fixing lugs allowing screw-mounting on chilled-ceiling surfaces.

Use

Functions

Ordering

Equipment

combinations

Mechanical

design

Summary of content (4 pages)

PAGE 1
Dewpoint sensor Signal converter 879 FA-H3 FU-IH3 FU-IH3 FA-H3 The FA-H3 dewpoint sensor is used to detect condensation on chilled ceilings. • For direct connection to the PRONTO PRT-H3 individual room controller • For connection to other controllers with the FU-IH3 signal converter Use The FA-H3 dewpoint sensor is used to prevent condensation forming on the surfaces of chilled ceiling installations.
PAGE 2
Accessories FU-IH3 Signal converter If the FA-H3 dewpoint sensor is used with PRONTO IRC controller types PRRA, PRRB, PRU..., PRFB-A or PRFB-V, and PRT/F, or with other controllers, the FU-IH3 signal converter should be used. Mounting notes Mounting instructions (Ref. 35672) are enclosed with the sensor. The dewpoint sensor should be fitted to the chilled ceiling at the coldest point, i.e. directly at the water inlet.
PAGE 3
Connection diagrams FA-H3 PRT-H3 50688 9 4 FA-H3 with FU-IH3 FA-H3 FU-IH3 1 2 PRRA, PRRB FA-H3 2 3 PRU FA-H3 4 50248 FU-IH3 1 AC 24 V 2 3 4 PRFB-A PRFB-V AC 24 V 3 4 50249 50380 5 4 5 8 5 9 6 5 6 9 6 10 7 7 7 All dimensions in mm 50687 4 15,5 Dimensions FA-H3 FU-IH3 1 AC 24 V 75 67,5 30 4 60 The FU-IH3 Signal converter The FU-IH3 signal converter is typically used for the FA-H3 dewpoint sensor in combination with PRONTO IRC controller types PRRA, PRRB, PRU..
PAGE 4
Technical data FU-IH3 Connection terminals FU-IH3 Supply voltage (input) Voltage tolerance Power consumption AC 24 V, 50 Hz (SELV, PELV) ±15% 1 VA On/off output Input signal Indication of condensation Volt-free change-over contact DC 24 V, 1 A FA-H3 sensor signal LED Connection terminals Screw terminals for 2.5 mm2 wire Protection class Protection standard III IP50 to IEC529 General ambient conditions: Operating temperature Storage and transport To DIN-IEC 68-2-1/2 0 ... 70 °C - 25 ...