IS MY PRESSURE SWITCH FAULTY?
1. If the pressure switch is faulty the pump won't turn on or off.
2. The pressure switch won't turn off the pump if there is no water (ie run dry)
3. If the pump is cycling (ie turning on and off) frequently (every 10 secs or so) check for these two main problems:
a) lift the pressure tank, if its heavy the bladder is full of water and the bladder is broken.
b) The check valve is faulty
There may be other causes but these above are the main ones. Other causes might be:
I) The electric points have worn out or rust has stopped it working. Or bugs have shorted it out, or water has blown it up. Electricity and water do not mix. A cover over the pump is essential if it is outside.
II) Dirt has built up in the little hole into the diaphragm at the back of the switch, and stops the switch getting the water pressure, to work the diaphragm.
III) The setting of the switch for cut off, is too high for the pumps performance, which may have some wear with age.
IV) Rubbish may be -blocking the impellers, a blocked strainer, which starves the pump for water, and will not allow it to build up pressure and slowing water flow . Check settings with pressure gauge.
V) The pump may have run dry, which stops it reaching its potential, as the impeller is distorted or melted.
As pressure Switches ALWAYS work in conjunction with a pressure tank. I have included information on them as well.
A tank should last for 5 years, unless in a rusty position outside, where birds can mess on it and rust it out. Pressure tanks have a rubber diaphragm sealed inside and air pressure around the rubber to allow the water to put pressure on the air. The capacity of the tank is usually in litres and the system will allow 1/3 of that capacity before the pump will start up. For example a 9 litre tank will allow 3 litre draw off, before the pump will start. Air pressure setting - Normally inflated to 10% less than the pump cut in pressure; Example – pump cuts in at 20psi, then the tank will be inflated to 18psi.
IS MY PRESSURE TANK FAULTY?
If the pump cycles too often or continuously cycles –
a) The tank has no air in it – check gauge
b) Tank is full of water, and water comes out the air valve – diaphragm shot – replace.
c) Pressure switch set too low, and needs to be lifted, to slow down the cycling.
d) Sometimes the tank is too small for the job, and needs a larger tank, to allow more water to be drawn off before turning on.
DETAILED PRESSURE SWITCH SPECIFICATIONS
Pressure sensor type Electromechanical pressure sensor
Pressure sensor name XMP
Pressure sensor size 12 bar
Fluid connection type G 1/4 (female) conforming to ISO 228
Controlled fluid Sea water (0...70 °C) , Fresh water (0...70 °C) , Air (0...70 °C)
Cable entry 2 entries incorporating Pg 13.5 plastic cable gland, cable outer diameter: 9...13 mm conforming to NF C 68-300
Contacts type and composition 2 NC snap action
Product specific application - Pressure switch type of operation Regulation between 2 thresholds
Electrical connection Screw-clamp terminals, clamping capacity: minimum : 2 x 4 mm²
Electrical circuit type Power circuit
Scale type Adjustable differential
Local display Without
Adjustable range of switching point on falling pressure 0.3...10.3 bar
Adjustment range high setting 1.3...12 bar
Possible differential minimum at low setting 1 bar
Possible differential minimum at high setting 1.7 bar
Possible differential maximum at high setting 8.4 bar
Destruction pressure 30 bar
Type of decompression valve Without
Control type Without
Terminal block type 4 terminals
Pressure actuator Diaphragm
Materials in contact with fluid Canvas covered nitrile, Chromated zinc alloy
Enclosure material PA impregnated with fibreglass
Operating position Any position
Operating rate 10 cyc/mn
Repeat accuracy < 3.5 %
[Ui] rated insulation voltage 500 V conforming to EN/IEC 60947-1
[Uimp] rated impulse withstand voltage 6 kV conforming to EN/IEC 60947-1
Resistance across terminals <= 25 MOhm conforming to NF C 93-050 method A
<= 25 MOhm conforming to IEC 60255-7 category 3
Electrical durability 700000 cycles (2.2 kW, operating rate: 10 cyc/mn, load factor: 0.4, 400 V AC 3 phases)
600000 cycles (1.5 kW, operating rate: 10 cyc/mn, load factor: 0.4, 230 V AC 3 phases)
500000 cycles (3 kW, operating rate: 10 cyc/mn, load factor: 0.4, 400 V AC 3 phases)
1000000 cycles (1.5 kW, operating rate: 10 cyc/mn, load factor: 0.4, 400 V AC 3 phases)
Mechanical durability 1000000 cycles
Setting Knurled knob and nut
Terminals description ISO n°1 (1-2)NC , (3-4)NC
CAD overall depth 98 mm
CAD overall height 125 mm
CAD overall width 57 mm
Ambient air temperature for operation -25...70 °C
Ambient air temperature for storage -40...70 °C
Vibration resistance 3 gn (f = 10...500 Hz) conforming to IEC 60068-2-6
Shock resistance 50 gn conforming to IEC 60068-2-27
Class of protection against electric shock Class I conforming to IEC 60536
IP degree of protection IP54 conforming to EN/IEC 60529
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