Maritime Geothermal TF-45, Installation And Service Manual

Page: 54 / 89

Page 54 001223MAN-05 1-Jul-2017
HYDRONIC TROUBLESHOOTING - AQUASTAT
Fault Possible Cause Verification Recommended Action
No Y1A signal to
heat pump
Incorrect aquastat setup. Aquastat does not indicate S1 on the
display.
Correct the setup.
Faulty aquastat to heat pump
wiring.
24VAC signal present across Stage 1
NO and COM of the aquastat but not
present across Y1A and CA of the termi-
nal strip.
Correct or replace wiring.
Faulty aquastat. No 24VAC between Stage 1 NO and
COM of the aquastat when S1 is indicat-
ed on the aquastat display.
Replace aquastat.
Faulty aquastat. 24VAC is present across 24Vand COM
of the aquastat but there is no display.
Replace aquastat.
Faulty wiring between heat
pump and aquastat.
24VAC is not present across 24V and
COM at the top of the aquastat.
Correct the wiring.
Faulty transformer Transformer breaker is not tripped,
230VAC is present across L1 and L3 of
the compressor contactor but 24VAC is
not present across R and C.
Replace transformer.
No display on
aquastat.
Transformer breaker
tripped.
230VAC is present across L1 and L3 of
the compressor contactor but 24VAC is
not present across R and C.
Push breaker back in. If it trips again
locate cause of short circuit and cor-
rect.
No Y2A signal to
heat pump
Incorrect aquastat setup. Aquastat does not indicate S2 on the
display.
Correct the setup.
Faulty aquastat to heat pump
wiring.
24VAC signal present across Stage 2
NO and COM of the aquastat but not
present across Y2A and CA of the termi-
nal strip.
Correct or replace wiring.
Faulty aquastat. No 24VAC between Stage 2 NO and
COM of the aquastat when S2 is indicat-
ed on the aquastat display.
Replace aquastat.
Faulty aquastat to heat pump
wiring.
24VAC not present across Stage 1 C
and COM of the aquastat.
Correct or replace wiring.
Faulty aquastat to heat pump
wiring.
24VAC not present across Stage 2 C
and COM of the aquastat.
Correct or replace wiring.
Setting(s) not
retained
Faulty aquastat E2 error message. Can cause the unit
to trip a safety control if the setting is too
high or low.
Replace aquastat.