Honeywell L7224A Installation Instructions Manual page 11

L7224A,C; L7248A,C,L OIL AND ELECTRIC BOILER ELECTRONIC AQUASTAT
System Diagnostic
Condition Condition
Boiler is hot, Display is ON.
house is cold.
Boiler is hot, Display is ON.
no hot potable
water.
ZONE 2
CIRCULATOR
R845A RELAY ZONE 2
1 POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2 CONTROL CASE MUST BE CONNECTED
TO EARTH GROUND. USE GROUNDING
SCREW PROVIDED.
Table 11. Troubleshooting Guide
Check
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.
ELL setting (L7248L only)
Boiler above LL? If yes, check 120
Vac at ZR-L2 (only L7248L with
ELL set On)
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)
"duu" setting
Check DHW Module and DHW
Sensor
TO ADDITIONAL R845A
RELAYS FOR OTHER ZONES
6
5
3
4
1
2
ZONE 2
LOW VOLTAGE
THERMOSTAT
Fig. 9. L7224A,C multizone system with circulator connections.
• 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 control.
• If yes, check zone relays, circulators and
wiring.
• Set ELL to Off for multizone system (see Fig.
11).
• Set ELL to On for External Low Limit (see
Fig. 13).
• If no 120 Vac, check C1-C2 (see above).
• If yes, check the External Low Limit control.
• 24 Vac on T-T (or 0 Vac on ZR-L2), check
wiring to water heater
• Wiring OK, check the water heater
• 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
1
L1
L7224
L2
(HOT)
SENSOR
ZR
L1
LINE
VOLTAGE
L2
CIRCULATOR
C2
B2
C1
LINE
VOLTAGE
B1
OIL BURNER
RELAY
ZC
11
®
CONTROLLERS
Action
LOW
VOLTAGE
THERMOSTAT
2
T
T 3
2
1
M27115
68-0281EFS—07