Testing the full-tank float switch (or pressure switch) circuitTable 10:
Test Test Description Notes Meter Setting + Probe Input Normal Result Interpretation
IF SWITCH IS NORMALLY OPEN (N.O.), cf. figure 26
10 POWER ON
voltage at terminals
3 and 4
chose one of
these two tests
V DC V ... a) 0 – 2 V
b) 5 V
if a) switch closed (or circuit shorted)
- pump off
if b) switch open (or circuit broken)
- pump on
10 resistance between
switch wires,
disconnected from
controller
Ω Ω ... a) < 100 Ω
b) > 10 kΩ
if a) switch closed (or circuit shorted)
- pump off
if b) switch open (or circuit broken)
- pump on
IF SWITCH IS NORMALLY CLOSED (N.C.), cf. figure 26
11 POWER ON
voltage at terminals
4 and 5
chose one of
these two tests
V DC V ... a) 0 – 2 V
b) 5 V
if a) switch closed (or circuit shorted)
- pump on
if b) switch open (or circuit broken)
- pump off
11 resistance between
switch wires,
disconnected from
controller
Ω Ω ... a) < 100 Ω
b) > 10 kΩ
if a) switch closed (or circuit shorted)
- pump on
if b) switch open (or circuit broken)
- pump off
See schemes on previous page for illustration of testing
Testing the full-tank float switch (or pressure switch) circuit9.4