Benchmark 750 – 1000 Boiler User Manual - INTERNATIONAL
CHAPTER 8 – TROUBLESHOOTING GUIDE
OMM-0119_0A
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
Page
105
of
170
GF-130-I
Ph.: 800-526-0288
11/03
/2016
TABLE 8-1: HEATING BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
HIGH GAS
PRESSURE
1.
Incorrect supply gas pressure.
2.
Defective SSOV Actuator.
3.
Defective
High Gas Pressure
switch.
1.
Check to ensure gas pressure at inlet of SSOV does not
exceed
14” W.C. (3.49 kPa)
2.
If NATURAL GAS supply pressure downstream of SSOV
Actuator cannot be lowered to the range of
2.0” ± 0.4” W.C.
(498
± 100 Pa)
using the gas pressure adjustment screw (see
section 4.3, step 10), the SSOV Actuator may be defective.
3.
Remove the leads from the High Gas Pressure switch. Measure
continuity across the common (C) and normally closed (NC)
terminals with the unit not firing. Replace the switch if continuity
does not exist.
HIGH WATER TEMP
SWITCH OPEN
1.
Faulty Water temperature switch.
2.
Incorrect PID settings.
3.
Faulty shell temperature sensor.
4.
Unit in MANUAL mode.
5.
Unit setpoint is greater than Over
Temperature switch setpoint.
6.
System flow rate changes are
occurring faster than units can
respond.
1.
Test the temperature switch to insure it trips at its actual water
temperature setting.
2.
Check PID settings against menu default settings in Chapter 3. If
the settings have been changed, record the current readings
then reset them to the default values.
3.
Using the resistance charts in the Appendix C, Measure the
resistance of Shell sensor and BTU sensor at a known water
temperature.
4.
If unit is in MANUAL mode, switch to AUTO mode.
5.
Check setpoint of unit and setpoint of Temperature switch;
Ensure that the temperature switch is set higher than the unit’s
setpoint.
6.
If the system is a variable flow system, monitor system flow
changes to ensure that the rate of flow change is not faster than
what the units can respond to.
HIGH WATER
TEMPERATURE
1.
See HIGH WATER
TEMPERATURE SWITCH OPEN.
2.
Temp HI Limit setting is too low.
1.
See HIGH WATER TEMPERATURE SWITCH OPEN.
2.
Check Temp HI Limit setting.
IGN BOARD
COMM FAULT
1.
Communication fault has occurred
between the PMC board and
Ignition/Stepper (IGST) board.
1.
Press
CLEAR
button and restart unit. If fault persists, contact
qualified Service Personnel.
