26
2.
3.
4.
Plug in a new control panel. If the problem is corrected, replace the control panel. If the problem
persists, proceed to step 3.
Check the voltage at the transformer secondary. See section A15, page 57, for transformer testing
instructions. If the voltage is bad, replace the transformer. If the voltage is good, proceed to step 4.
Check the circuit board transformer connections. If the connections are loose or oxidized, repair the
connections and retest the system. If the problem persists, replace the circuit board.
7.4 Testing Flow Switch
1.
2.
3.
Verify the ow switch directional arrow is pointing in the direction of ow towards the heater return
tting outlet. If the ow switch orientation is incorrect, loosen or tighten the switch no more than 1/2
turn, being careful not to bottom out the switch in the tting. The switch’s ow arrow must be parallel
to the tee tting as shown ( g. A). Test the system operation. If the condition persists, proceed to
step 2.
Remove the switch from the tting making note of the number of turns (revolutions) it takes to do so.
Visually inspect the switch for debris interference or damage. If debris is present, remove the debris,
then reinstall the switch with the same number of turns as originally installed. Test the sytem. If the
switch is damaged, replace the switch and retest the system. If the condition persists, proceed to
step 3.
Test the switch operation with an ohmmeter (set to 1000-2000k range) for continuity across the
switch terminals. Measure resistance across the switch terminals for in nite resistance with the
magnet arm not touching the switch body ( g. B), and for continuity (Ø ohms) with the magnet arm
touching the switch body ( g. B). If the ow switch tests OK, check the wiring harness. If the wiring
harness tests OK, replace the circuit board.
fig. A
fig. B
Incorrect
Orientation
Correct
Orientation
FLOW
Arrows
aligned
FLOW
Arrows
not
aligned
Open
Continuity 0 ‰
(Pump ON)
Closed
‰
Infinite ‰
(Pump OFF)
‰