
www.freedomhp.co.uk
©G Hendra Nov 18
18
E101, E102, E201 and E202
E101 shows on the indoor unit if the outdoor unit has been off for more than 5 minutes
E201 and E102 is a communication error between indoor control box and the outdoor unit.
E202 shows on the outdoor unit if the indoor unit has been off for more than 5 minutes
The communication is carried out using the F1 and F2 cable between the two units.
Communication errors the most common cause of incorrectly diagnosing faults with PCBs.
The hardest thing for an engineer to do is work out which end has the communication error.
In the middle of the control box (indoor unit)
PCB there are two leds, the red one shows the
communication leaving the control box, the
orange / green led shows the communication
coming back from the outdoor unit. If there is a
comms error E201 one or both of the leds will
not be lit indicating which PCB is at fault.
NOTE
if you kill the power to the indoor unit for
3 mins but leave the outdoor unit powered.
Now power up the indoor unit, note how if you
ask it for the flow temperature it shows -50C
this is because the indoor can’t see the flow
sensor which is in the outdoor unit. Note also
that the unit thinks its 0C outside; again the indoor unit can’t see the outdoor sensor.
After about 5 mins everything will sort itself out. In the mean
time you will see E201 error on the indoor remote and E202 on
the outdoor unit display
E201 also indicates issues with the outdoor unit, it’s worth
looking at the display in the outdoor unit to see if another fault
code is showing, this will indicate the fault in more detail.
The comms is a series of pulses. The outdoor unit
communicates with the positive part of the ac sine wave and the
indoor unit with the negative part; we measure the signal using
the DC range on our meters so we can see half of the
communication at one time to identify faults. See below.
Advanced tip:
With a min max multi meter you
can test both pcbs at once, set
the meter to DC Volts, set min
max running hold red lead on F1
and Black lead on F2. After 10
seconds check the max and min
Voltages, if there is a negative
reading the indoor board is
good, if there is a positive
reading the outdoor is ok.