Gestra TA 7 230VAC Programschalter

Data Sheet 818557-02 Issue Date: 07/17
Programme-Controlled Blowdown System
TA 7 Description
Technical Data
Electronic unit for the generation of periodic pulses to initiate a blowdown cycle via the GESTRA rapid-action
intermittent blowdown valve type MPA 46 or 47, i.e.
automation of intermittent boiler blowdown. Equipment for steam boilers to TRD 401, section 6.4.
The programme-controlled blowdown system consists of an electronic cycling timer, a three-way solenoid valve and
a strainer.
The equipment meets the German regulations for use in steam-boiler plants operating without constant supervision
or with limited supervision (TRD 602 and TRD 604, sheet 1).
Three-Way Solenoid Valve 340 C
Function The cycling timer type PRS 8 generates a control pulse which, after the preset blowdown interval, operates the three-way
solenoid valve. This in turn actuates the rapid-action blow­ down valve by means of compressed air or pressurized
water and closes it again at the end of the pulse (blowdown) duration.
The blowdown interval and the pulse duration can be coarsely preset with a code switch. Final adjustment is carried out with
the aid of two potentiometers.
For test purposes and in the event of power failure the three-way solenoid valve can be operated by hand.
A push-button manual override is provided on the solenoid valve which allows a test of the blowdown valve as
required by certain regulations in force.
Connection ¼", EN ISO 228-1 Max. service pressure 16 barg (230 psig) Min. differential pressure required
for opening and closing 0.5 bar (7.2 psi) Duty cycle 100 % Position of installation
as required Code letters for connections P = Pressure connection A = Valve outlet
R = Exhaust or drain outlet Supply voltage 115 V, 50 Hz, 15 VA, in rush 30 VA
or 230 V, 50 Hz, 15 VA, in rush 30 VA or optional 24 V DC 8 W Protection
IP 65 Maximum permissible ambient temperature 55 °C
Design
Approx. weight 0.9 kg
The cycling timer PRS 8 is mounted in an appliance plug socket fitted on the three-way solenoid valve.
Strainer
Technical Data
Connection ½", EN ISO 228-1
Cycling Timer PRS 8 Interval time toff (blowdown interval) Adjustable within a range of 0.5 h to 10 h
Pulse duration ton (blowdown duration) Adjustable within a range of 0.5 s to 10 s
Indicators One LED mains supply One LED pulse duration Supply voltage 115 V – 230 V, 50 – 60 Hz
or 24 V DC Protection
IP 65 Permissible ambient temperature 0 °C to 60 °C Cable entry
PG cable gland for 0.6 to 7 mm cable Approx. weight 60 g
– continued –
Material Body: gun metal RG 5 Filter cartridge: austenitic stainless steel 1.4571
Mesh size 0.5 mm Approx. weight 0.3 kg
Control Fluid Compressed air or pressurized water, 4 to 8 barg (58 to 116 psig) depending on the blowdown valve used and
the boiler pressure (see chart in data sheet MPA 46,
MPA 47).
Wiring Diagram