Enertech VS Series - Safety Controls and Diagnostics

39
IOM, VS/VT Models, Rev A Enertech Global
Loop Pump Circuit Breakers
The loop pump(s) and HWG pump are protected
by control box mounted circuit breakers for easy
wiring of pumps during installation. Circuit breakers
eliminate the need to replace fuses.
Figure 12: ECM Board Layout
Safety Controls
The lockout board receives separate signals for
high pressure, low pressure, load heat exchanger
freeze, source heat exchanger freeze, condensate
overow, and hot gas temperature limit faults. Upon
a continuous 30-second measurement of all faults,
except the high pressure fault, the compressor
operation is suspended. The high pressure fault is
immediate. The appropriate LED(s) ash for each
fault. Once the unit is locked out (see fault retry
below), an output of 24VAC is energized on the
“L” terminal for remote indication of a fault at the
thermostat.
Figure 13: Lockout Board Layout
Low Pressure-LP: If the low pressure switch is open
continuously for 30 seconds, the compressor
operation will be interrupted, and the control will
go into fault retry mode. At startup, the low pressure
switch is not monitored for 30 seconds to avoid
nuisance faults. (If the low pressure switch is open
before startup then the unit will not start upon
receiving an Y1 call and will lock out instead.)
High Pressure-HP: If the high pressure switch opens,
the compressor operation will be interrupted, and
the control will go into fault retry mode. There is no
delay between the time the switch opens and the
board entering into fault retry mode. There is also
no delay of switch monitoring at startup. (If the high
pressure switch is open before startup then the unit
will not start upon receiving an Y1 call and will lock
out instead.)
Load Heat Exchanger Freeze-T1: When in cooling
mode, if the heat exchanger temperature is lower
than 30°F for 30 continuous seconds, the compressor
operation will be interrupted, and the control will go
into fault retry mode. This sensor is located on the
refrigerant line in between the heat exchanger and
TXV (refrigerant inlet of heat exchanger in cooling
mode).
Source Heat Exchanger Freeze (Flow Sensing)-T4:
When in heating mode, if the heat exchanger is
lower than setpoint for 30 continuous seconds, the
compressor operation will be interrupted, and the
control will go into fault retry mode. The setpoint
is 15°F for closed loop (A-FRZ jumper removed)
and 30°F (A-FRZ jumper installed) for open loop.
At startup, the ow sensor is not monitored for
30 seconds to avoid nuisance faults. This sensor
is located on the refrigerant line in between the
source heat exchanger and TXV (refrigerant inlet of
heat exchanger in heating mode).
Condensate Overow: If water touches the
condensate overow sensor for 30 continuous
seconds, the compressor operation will be
interrupted. The control will go into fault retry mode.
There is no delay of switch monitoring at startup.
Hot Gas Line Temperature limit (T2>220°F): When
T2>220°F for 30 continuous seconds, the compressor
operation will be interrupted. The control will go into
fault retry mode.
Section 9: Controls
O/B Y1 G W1 R ODD W2 Y2 C
W1
COM
24VAC
COM2
XFMR
SEC
CFM
ECM
Board
CC
HP
Lockout
Board
HWG W2 G W1 Y2 R_2 R_1 C_2 C_1
AFRZ
TEST
O/V
STATUS
LP
FS
CO
A
C
R
Y1
L
O O
CCG1
CCG
UART 1 2 3 4
FSW