9
Troubleshooting Guide -
Tranquility
®
Digital (DXM2) Packaged Units
Rev.: 01/15/14
Replace
DXM2
No
Unit runs but
does not satisfy
Yes Yes
The unit is running.
However, there is
a load issue. The
home is losing or
gaining more than
the capacity of the
heat pump.
If water fl ow and airfl ow are
good, then verify refrigerant
charge. Calculate superheat and
subcooling.
A-H
Troubleshooting Flow Chart
Continued
The unit runs
but auxiliary
heat is not
working
Yes
Is the thermostat
calling for
auxiliary heat or
emergency heat?
Verify that
confi guration is set
to auxiliary heat in
thermostat. See
section 2.2.2 on
page 55.
No
Does unit have
208-240V at
auxiliary heat
strip?
Turn breaker
on in panel or
in auxiliary heat
control
B-C
No
Does DXM2
have 24 VDC
at EH1 and/or
EH2?
Yes Yes
A-I
Replace
wire harness
No
Does the heat
strip control
board have the
same 24 VDC as
the DXM2?
Yes
Replace heat
strap board
Yes
Verify the Water Side
Performance
HE = Heat Extraction in
BTUs (Heating)
HR = Heat Rejection in
BTUs (Cooling)
Calculate using the formula
found on A-G.
Check with performance
data. Is unit within 10%?
A-G
Verify load using a
manual J program.
You may also need to
perform a blower door
test for true infi ltration
and thermal imaging
for locating heat loss.
Also consider a duct
blast to verify that
air is being delivered
properly.
Yes
Adjust charge if needed to proper
superheat and subcooling ranges.
No
Then
No
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