27
You may avoid inconvenience and service calls by checking these points before you call for service:
IF YOUR SYSTEM IS NOT HEATING OR NOT GIVING ENOUGH HEAT . . .
POSSIBLE CAUSE
WHAT TO DO
Thermostat is not set correctly
Reset thermostat
Burner is not operating properly
C
heck flame. If it is yellow, the burner is not getting enough air.
Or, if flame is blue and noisy and seems to lift off the burner, the
burner is getting too much air. Contact your service technician.
No electric power to boiler
Check over-current protection. Check to be sure electric power
supply circuit is “ON”.
Controls out of adjustment
Reset according to instructions.
Radiators not heating
Open radiator vents to excess air. Check flow control valve (if
used). It may be in closed position.
Circulating pump not running
Check over-current protection. Check relay operation.
Poor electrical contact
Check all control terminals and wire joints.
Chimney flue is blocked
Have the chimney professionally cleaned.
Circulator running when boiler water
temperature is below low limit set
point (tankless coil boilers only)
Honeywell L7248L control - confirm ELL parameter on L7248L
control set to ON.
Refer to control instructions furnished with boiler.
RELIEF VALVE LEAKING . . .
POSSIBLE CAUSE
WHAT TO DO
Corrosion and/or deposits on seat.
Open valve manually. Allow water to run and clear valve seat.
Water logged expansion tank
Drain tank, see instructions.
HAVE YOUR SERVICE TECHNICIAN CHECK ANY PROBLEM YOU
ARE UNABLE TO CORRECT.
SERVICE HINTS
15
10
5
0
5
4
3
2
1
m H
ead
1
2
3 4 5
US GPM
5
10
15 20
m /h
3
H
ead (f
eet)
Figure 17 - Pump Curves
Taco 007 Pump Curve
Grundfos UP15-42F Pump Curve
PN 240013023, Rev. B [12/31/2020]
