18
8.1B No Heat or Not Enough Heat (All Models)
• Symptoms: Circulation pump (heating pump) not turning, panel heat indicator not lit,
panel is ashing FL2.
Standard Troubleshooting Approach
Turn power off. Disconnect
ow switch wire from board
(Fig. 4). Turn power on.
Does the FL2 error message
go away?
1. Remove wires at board.
2. Test ow switch with
ohmmeter for continuity
across switch wires (Fig.
5). Does meter read
continuity (0 ohms)?
Remove ow switch and in-
spect for debris interference.
Remove debris if present.
Test switch for continuity
(0Ω) when closed and for
innite Ω when open (Fig. 5).
Does switch operate cor-
rectly?
Install switch making sure
ow arrow points in direction
of ow and switch doesn’t
bottom out in tting (Fig. 7).
Retest system.
Is wire shorted?
Replace wire.
Make sure wire
is not shorted
when installed on
switch. For models
where the wire is
removable.
Replace ow switch.
Replace circuit
board.
Yes
No No
Yes
Yes
Yes
No
No
Fig. 4
Fig. 5
Infinite Ω
Continuity 0 Ω
Fig. 6
FLOW
Incorrect
Orientation
Correct
Orientation
Correct
Orientation
FLOW
Pipe
End View
correct
incorrect
Arrows
not
aligned
Arrows
aligned
Closed
DCV ACV
DCA
OFF
1000
200
20
2000m
200m
2000k
200k
20k
2000
200
10A
200m
20m
2000µ
200µ
Ω
+
750
200
DCV ACV
DCA
OFF
1000
200
20
2000m
200m
2000k
200k
20k
2000
200
10A
200m
20m
2000µ
200µ
Ω
+
750
200
Open
DCV ACV
DCA
OFF
1000
200
20
2000m
200m
2000k
200k
20k
2000
200
10A
200m
20m
2000µ
200µ
Ω
+
750
200
Flow
Cable