M3
CONDENSING WATER BOILER
38
34-1115 12/15
14 TROUBLESHOOTING GUIDE
Problem Probable Cause Corrective Action
Starting or Pre-purge
Failure
Power Supply Check fuse and/or circuit breaker.
On-Off Switch
Check if On-Off switch is illuminated when on. If not check
panel fuse or incoming power.
Temperature Control
TempTrac
Check that the operating temperature control is set higher
than the temperature of the boiler. See Table 10.8 for
indications of control or sensor faults.
Remote enable/disable open
See Table 10.8 for indication of condition. Enable boiler or
place jumper between terminals R1-R2.
Electronic Low Water Cut-off
(when installed)
Check internal ELWCO board for indication of failure. The
red LED indicates a safe condition. Manual reset is required.
Gas Pressure Switches
(when installed)
Gas pressure switches are attached to the gas train. Check
for a tripped condition indicated by the manual reset button
on the switch. Correct low gas pressure condition at the
supply.
High Temperature Limiting Device
One manual, one auto reset limit device, set at 210F and
200F respectively, located at the control well on the top head
of the tank. A high temperature condition may be caused by
a failure of the TempTrac, temperature sensors. The failure
can require manual reset depending which limit is tripped.
Combustion Air blower
Check if fan control relay is closed
Blower motor may have failed.
Fan VFD may be defective. Verify proper voltage.
Air-proving Switch
(if blower is functioning)
Check switch contacts are closed.
Check for 120V at the N.O. side of air switch
Check for 120V at the common side of air switch
Check if switch tubing is connected on both ends
Flame Safeguard Control Check for bad ground or bad control. Replace if necessary.
Remote Proving Interlock
When terminal C1 and C2 are used a proving circuit for
remote equipment, failure to close this circuit within the
allotted time for Call-for-Heat will prevent operation and
cause an alarm indication. Check for proper operation and
proving of remote equipment.
Loose Wire Connections Check connections to all components
Flame Failure
Power Supply
120 VAC is required for operation. Low voltage can cause
failure. Voltage below 110 VAC must be investigated.
Flame Safeguard Control Check for bad ground or bad control. Replace if necessary.
Hot Surface Igniter
Check resistance at room temperature and then the
amperage draw during heat-up. Replace if the measured
amperage is not within 3.5 to 5.0 Amps or if measured
resistance is not within 40-100 ohms (at room temperature).
Also, check for overheating condition due to damaged
refractory around igniter.
Air-proving Switch
Check if switch is bouncing. Adjust or replace. Check VFD for
proper speed settings.
Gas Pressure
Check for proper inlet static and dynamic gas pressure, 3.5”
WC minimum.
Combustion
Inadequate flame signal may result from improper
combustion. Adjust to proper CO2 levels at low fire. Inability
to achieve proper CO2 throughout the modulation range may
be caused by a defective gas valve, a defective regulator or
blockage in the in the burner or combustion air supply.
Grounding
Check for proper ground from the flame control to the burner
housing.
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