Tranquility
®
D i g i t a l ( D X M 2 ) — Tr o u b l e s h o o t i n g G u i d e
R e v. : 1 0 M a r c h , 2 0 1 5
4
G e o t h e r m a l H e a t i n g a n d C o o l i n g
See Section 3.2
on page 56.
Troubleshooting Flow Chart
My unit has
a Modulating
Valve. Is valve
opening?
Is the valve having
trouble shutting
completely and/or
is the unit
locking out?
No
Continued
Yes
Check
What are the ∆T set points?
Control defaults are 7°
heating and 10° cooling.
Open loop units with EWT
less than 50° will need
to lower ∆T to 4-5° in the
heating mode.
Valve opens or
closes correctly
Yes
Verify A0-2
jumper is in
10V position.
A-V
Be sure unit
is configured
for Modulating
Valve.
Verify
Valve and
powerhead
alignment
Manually open the valve
100%. Remove powerhead
from valve with powerhead
still energized. Then verify that
the notches on valve body are
in the correct position.
Third notch aimed down in
unit position.
Then reattach powerhead.
A-C
Next Page
Replace pump
power head
No
Is there voltage
to the pump?
(197-254V)
A-O
The unit starts
but the pump
does not
Check that the
A0-2 jumper on
DXM2 board is in
PWM position
Yes
A-V
Yes
Replace
wire harness
Yes
Yes
No
No
A-P
Check DC Voltage
at DXM2 Board
A0-2-Ground = .5-10 VDC
Is voltage in this range?
Does the low
voltage wiring
have a broken
wire?
Check DC Voltage
at DXM2 Board
T1-Ground = 3-4 VDC
(Pump off)
0-2 VDC
(Pump on)
Is voltage in this range?
No
Replace
DXM2 board
A-J
Yes
No
Yes
Verify how the units are
configured in the thermostat
(refer to ‘Section 3.3 - Unit
Configuration’ on page 53).
Be sure unit is configured for
‘Variable Speed Pump Single’
if unit is on it’s own loop. If unit
shares a loop with other units,
then ensure that the unit is
configured for ‘Variable Speed
Pump Parallel.’
B-L
Pump may be
locked. Pull
pump motor.
Can you free
impeller?
Replace pump
motor
