A31 MODEL – CONSTANT DIFFERENTIAL THERMOSTATS WITH AUXILIARY SWITCH
A21 MODEL – CONSTANT DIFFERENTIAL THERMOSTATS WITHOUT AUXILIARY SWITCH
The A21 and A31 type have two main 3-4 and 3-2 contacts.
3-4 close to increase the temperature
3-2 open to increase the temperature
A31 type thermostats have an auxiliary switch located in series with the main switch. The auxiliary switch is operated by rotating the shaft anticlockwise from MIN position to STOP. The A21 and A31 types are a constant differential thermostats and therefore the differential between cut-in and cut-out temperatures Is constant over the whole range.
The minimum differential that can be obtained is 3°C.
Calibration is carried out at a barometric pressure of 740 mmHg.
A21/A31thermostats are used to control the temperature in:
– air conditioners
– ice makers
– heat pumps
– drink vending machines
A21/A31 type thermostats are compact, robust, and small in size. All their components are made in conformance to Directive 2002/95/CE R0HS, and in particular they have no Cr VI, while the gas used is CFC FREE in compliance with environmental standards.
ELECTRICAL CHARACTERISTICS AND TERMINALS
The terminals are disconnectable tabs with two standard sizes:
6.3 x 0.8mm and 4.8 x 0.8mm
A31/A21 thermostats have 2 terminals for earth connections:
6.3 x 0.8mm and 4.8 x 0.8mm fastons
3-2 terminals: 16(4) A250V~µ
3-4 terminals: 16(13) A250V~µ
3-6 terminals: 16(13) A250V~µ
The capillary tubes are made of copper with 3µ tin finishing. They can be supplied covered with a white extruded sleeve. Standard length: 300mm with steps of 50mm up to 3000mm. Upon request we can supply capillary ends with bulbs or curl. To ensure correct position, it must be in contact with the coldest part of the appliance. There must be a good physical contact between the evaporator and at least the last 120 mm of the capillary, it is advisable to position this part of the capillary pointing slightly downwards. If there is insufficient space, the end of the capillary can be bent around the evaporator respecting the minimum bending radius.
ENEC 03 / UL / CSA