resideo Aquastat L7224U Manual Del Usuario página 11

System Condition
Boiler is cold, house Display is OFF.
is cold.
Display is ON.
TT-LED is OFF.
Display is ON.
TT-LED is OFF.
Display is ON.
TT-LED is ON.
B1 LED is ON.
Display is ON.
TT-LED is ON.
Boiler is hot, house Display is ON.
is cold. TT-LED is ON.
C1 LED is ON.
Display is ON.
TT-LED is ON.
C1 LED is OFF.
ZC LED is ON
Display is ON.
TT-LED is ON.
ZC LED is OFF
Boiler is hot, no hot Display is ON.
potable water
a
Refer to Table 3 for Display and LED locations.
b
ZC LED ON indicates ZC terminal power is OFF.
c
ZC LED OFF indicates ZC terminal power is ON.
L7224U OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT
Table 10. Troubleshooting Guide
Diagnostic Condition
b
.
c
.
Check
120 Vac system power.
24 Vac T-T.
24 V present; disconnect
thermostat, short T-T.
120 Vac at B1-B2.
Refer to Err on display.
120 Vac at C1-C2.
Boiler below the Low Limit
temperature, wait for boiler to go
above Low Limit temperature.
Boiler above LL? If yes, check for
120 Vac between ZC and L2.
Boiler Demand signal from the water
heater (either 120 Vac at ZR-L2, or
0 Vac on T-T; depends on
installation and "duu" setting)
"Zr" reads "On" (or "tt" reads "On")
"duu" setting
Check DHW Module and DHW
Sensor
11
a
.
Turn system power on.
No 24 V; replace controller.
Boiler starts, check wiring and
thermostat.
• If no, replace controller.
• If yes, check burner and
wiring.
—
• 120 Vac at C1-C2, check
wiring to pump.
• Wiring ok, is pump running?
If not, replace the pump.
• If pump is running, check
for trapped air or closed
zone valves.
—
• If no 120 Vac, replace
controller.
• If yes, check zone relays,
circulators and wiring.
• 24 Vac on T-T (or 0 Vac on
ZR-L2), check wiring to
water heater
• Wiring OK, check the water
heater
• "Zr" reads "OFF" but
120Vac on ZR-L2, replace
the control
• Set duu to ON if 120 Vac
water heater demand is
connected to ZR
• Set duu to OFF if
open/closed water heater
demand is connected to T-
T
• DHW Module not properly
connected and/or DHW
Sensor improperly
positioned
®
CONTROLLER
Action
69-1720EFS—13