American Dream Ultra Performance Geothermal Copper Series, Installation And Service Manual

Page: 41 / 60

25 MAY 2009 Page 41 000744MAN-02
HYDRONIC OPERATION TROUBLESHOOTING
Fault Possible Cause Verification Recommended Action
Low Suction
Pressure
(continued)
Faulty compressor, not
pumping. Pressures change only slightly from
static values when compressor is
started. Replace compressor.
Loop piping interchanged
(ie Loop 1 connected be-
tween Vapour 1 and
Liquid 2) Affected TXV’s do not seem to oper-
ate properly. Switch to cooling
mode and verify all liquid line tem-
peratures for each individual loop
switch. The liquid line for the loop in
use should be warmer than the oth-
ers, If loops are interchanged, the
wrong liquid line will be warmer. Pump the unit down and swap
the interchanged lines.
Loop field too small Charge is good, superheats are
good, vapor line temperatures are
low. Increase loop size.
High Suction
Pressure
(may appear to
not be pumping)
Leaking reversing valve. Reversing valve is the same tem-
perature on both ends of body,
common suction line is warm, com-
pressor is running hot. Replace reversing valve.
Heating TXV’s adjusted
too far open. Verify superheat. It should be be-
tween 8-14°F (3-8°C). Superheat
will be low if TXV’s are open too far. Adjust TXV to obtain 8-14°F
(3-8°C) superheat.
One or more heating
TXV’s stuck (too far
open). Adjusting the TXV does not affect
the superheat of the loop or the suc-
tion pressure. Low super heat, low
discharge pressure. Attempt to adjust the TXV all the
way out and all the way in a few
times to loosen it. Replace TXV if
this does not work.
Faulty cooling check valve
(leaking) Also low discharge pressure. Switch
to cooling mode. Unit operates cor-
rectly when loop is in use. Loop
lines get cold when loop not in use
instead of warming to ambient, com-
pressor frosts up. Identify the check valve. Try
switching modes a few times.
Replace if problem continues.
Compressor
frosting up
See Low Suction
Pressure in this section.
Heating TXV
frosting up heav-
ily TXV stuck almost closed
or partially blocked by for-
eign object. Adjusting the TXV does not affect
the superheat or the suction pres-
sure. Attempt to adjust the TXV all the
way out and all the way in a few
times to loosen it. Replace TXV
if this does not work.
Random high
pressure trip
(does not occur
while on site)
Intermittent Indoor circula-
tor. Verify wiring is good Correct the wiring or replace the
circulator.
Random manual
high pressure
trip (does not
occur while on
site) Faulty compressor contac-
tor. Points pitted or burned. Contactor
sometimes sticks causing the com-
pressor to run without the fan, trip-
ping the high pressure control. Replace contactor.