Laars boiler troubleshooting

Autonomous heating brings warmth and comfort to a home. A boiler is the ‘heart’ of such a system, and any fault occurring in it may impede or stop its work. Please, refer to the table below, find the cause of your problem and look for a solution.

Laars EBP0110 boilers troubleshooting

Code Solutions
F1 Boiler control internal error
F3 Gas valve status is on, with no call for heat
F4 Supply sensor error
F5 Tank sensor error (EBP only)
F6 Return sensor error
F8 OAT sensor unreliable
LO Lockout
OFF Controller is off
ICE Low temperature protection
F-l Switch off boiler and restart. If F-l repeats, replace boiler control.
F-3 In normal operation, the ignition control sends a “gas valve energized” signal to the boiler control, so the controller will be able to time its PI algorithms correctly. An F-3 fault code indicates that the ignition control is sending a signal that the gas valve has been energized, but there is no call for heat. The boiler control will not allow the Endurance to fire in this condition. This fault indicates that there is either something mis-wired on the boiler, or that the relay in this circuit has seized. Check the relay for seized contacts first, and if the relay is operational, check the wiring circuit on the boiler.
F-4 Check for damaged wiring or poor connection at sensor plug. If they are OK disconnect the sensor plug and check the resistance across the sensor terminals. The resistance of a good sensor is 10,000 ohms @ 77°F (25°C). Replace sensor if resistance is less than 500 or more than 20,000 ohms.
F-5 Correct in the same manner as F-4.
F-8 Check that the outdoor air sensor is installed properly, and that the wire and/or connection are not damaged. If okay, disconnect the sensor and check the resistance across the sensor terminals. The resistance of a good sensor is 10,000 ohms at 77°F (25°C). Replace sensor is resistance is less than 500 or more than 20,000 ohms.

Laars JVS boilers troubleshooting

# Symptom Cause Remedy
1. Pump not operating A. No power A. Check circuit breakers and power source.
B. Pump defective B. Replace.
C. Incorrectly wired C. Recheck wiring diagrams.
2. Pilot outage A. Inlet gas pressure too low A. Consult gas utility company. Inlet gas pressure to boiler should be 5.5” to 10.5″ water column on natural gas. 0.0″ to 13.0″ on propane gas.
B. Inlet gas pressure too high causing an unstable blowing pilot B. Pressure should be regulated within limits shown above.
C. Weak or defective thermocouple C. Replace thermocouple.
D. Damaged pilot or thermocouple D. Replace.
E. Dirty pilot E. Blow dust or lint out of pilot.
F. Plugged or undersized pilot orifice F. Clean or replace pilot orifice.
3. Flame roll-out on start-up A. Blocked flue A. Remove blockage.
B. Pilot out of position (delayed ignition) B. Correct pilot position.
C. Blocked heat exchanger or flue C. Clean and correct as necessary.
D. Refractory tile out of place D. Correct or replace tile as necessary.
E. Altered draft diverter E. Install factory-provided draft diverter.
4. Spillage at draft hood A. Cold chimney A. Allow boiler to operate 5 minutes to create draft action.
B. Vent pipe pitches down to chimney B. Reinstall vent pipe to pitch up from boiler to chimney.
C. Blocked chimney C. Remove blockage.
D. Draft hood altered D. Install factory-provided draft diverter.
E. Pre-fabricated chimney with incorrect cap E. Install U.L. listed vent cap.
5. Flame has lazy yellow tip A. Low primary air A. Correct manifold pressure according to rating plate. Correct orifice size if necessary. Clean burner ports if dirty. Verify correct fuel type.
6. Not enough heat A. Inadequate gas supply A. Gas meter too small. Gas line from meter to boiler too small.
B. Low manifold gas pressure B. Gas pressure on boiler manifold (at normal firing rate) should be adjusted to 4.0″W.C. natural gas, 9.0″W.C. propane.
C. Boiler size inadequate C. Replace with boiler of higher input.
D. JVS 100-225 only – Boiler not going to high fire. D. Check operation and setting of two-stage operating control.
7. Pump noisy A. Air in volute A. Bleed air from volute. Check pump alignment.
B. Worn coupling or bearings B. Replace worn parts.
8. Boiler pounding or knocking A. Too low water flow through boiler A. Check temperature rise between inlet and outlet boiler piping. 15°F to 25°F temperature rise is recommended. If temperature rise is over 25°F, increase pipe size or pump capacity or locate obstruction. Check for stuck closed zone valves.
Check for zone pumps not operating. Check for closed valve in system.
9. Boiler condensing A. Low water temperature A. Flue product moisture will condense at the start-up until the boiler water temperature reaches the normal operating conditions.
10. Pump cavitates or low water pressure at boiler gauge or bubbles in system at high temperature A. Defective fill valves or pressure regulator A. Replace.
B. Oversized expansion tank B. Replace.
C. Expansion tank piped incorrectly C. Repipe expansion tank to suction size of pump.
11. Pressure relief valve opens A. Water-logged expansion tank A. Drain 2/3of the water from the expansion tank.
12. Pilot is lit but main burners will not come on A. Gas valve not at “on” position (JVT) A. Turn knob to “on” position.
B. Boiler off on hi-limit control B. Check for low water flow or hi-limit setting.
C. Boiler incorrectly wired C.On single or multiple zone systems with zone valves, room thermostat should be wired to R & W terminals. For multiple zone systems with zone pumps, thermostats for extra zones should be wired to R & A terminals.
D. Boiler off on blocked vent switch D. Remedy as in symptom #4. Reset the manual reset switch.
E. Boiler off on flame roll-out switch E. Remedy as in symptom #3. Reset the manual reset switch.
F. Broken wire in thermostat circuit or defective thermostat F. Check continuity through thermostat circuit with wires disconnected from R & W.
G.JVS 100-225 Only – Two-stage operating control not functioning or loose contact. G.Check continuity and operation through two-stage operating control.
13. Boiler short cycles A. Heat anticipator in room thermostat set too low A. Increase setting (0.8 -1.0 is usually satisfactory).
B. Low water flow through boiler B. Increase size of pump or increase piping size.
C. Hi-limit switch may be set too low C. Increase setting to at least 20°F over outlet water temperature.

Laars LMH boilers troubleshooting

27 Internal error Flame rod to ground Check wiring / probe grounded, dirty probe
47 Flame rod to ground leakage Faulty flame detector Clean or replace flame detector
49 24VAC voltage low/high Faulty transformer Check/correct supply line voltage; replace faulty transformer
52 Motor tachometer fault Faulty fan / fan wiring fan circuit Check fan harness wiring for continuity; replace faulty
53 AC inputs phase reversed Reverse 24V hot/neutral – use common ground
61 Anti short cycle Call for heat will be held until timer resets Change ASC timer setting
62 Fan speed not proved Dirty / defective fan Clean or replace fan; check wiring
63 LCI off Safety chain interrupt Check flow switch, aux high limit, LWCO, gas pressure switches, condensate level and correct problem
69 Outlet high limit High limit tripped Determine cause: low/no flow, valves closed, settings and correct
80 DHW high limit Check pump, time delay, valves closed, etc. And correct overtemp
81 Delta T inlet/outlet limit
82 Stack limit Could be caused by high ambient temperature, or high return water temperature
88 Outlet T-rise limit
90 Heat exchanger high limit Diagnose / repair cause of high temperature
91 Inlet sensor fault
92 Outlet sensor fault
93 DHW sensor fault Faulty sensor or wiring Check wiring / replace sensor; condition can be caused by short
95 Stack sensor fault
96 OAT temperature sensor fault temperature sensor Faulty outdoor air is open or shorted Check wiring and sensor for short; replace sensor
105 Flame detected Flame exists at burner out of sequence Clean burner of soot or other debris that could when it should not be maintain flame
106 Flame lost in MFEP Unstable flame during
107 Flame lost early in Run lighting / flame proving equences Check venting, gas supply pressure, burner, fan, etc.
108 Flame lost in Run
109 Ignition failed Problem with ignitor, or other ignition-related device Check / replace ignitor, wiring; check for shorting in ignitor cable
113 Flame circuit timeout Flame not established within expected time limit Check all combustion components; purge gas; check ignition source
122 Lightoff rate proving failed
123 Purge rate proving failed
128 Fan speed failed / prepurge Fan did not reach expected RPM Check fan wiring; replace fan
129 Fan speed failed / preignition
130 Fan speed failed / ignition
131 Fan movement detected during standby Fan should not be moving when not powered Check for common venting problems or otherwise forced air
132 Fan speed failed during run Fan lost or gained speed during run sequence away from control spec Fan overheating or otherwise failing; check cable; replace fan
137 ILK failed to close No power at interlock ILK Check J5 pin 1 for power – if no power, confirm safeties are closed
248 CH outdoor temperature was invalid
251 CH ODR max outdoor temp- erature setDoint was invalid Confirm outdoor reset settings. An invalid adjustment has been made
252 CH ODR min outdoor temp- erature setpoint was invalid
253 CH ODR min water temp- erature setpoint was invalid
254 CH ODR temperature range was too small (min. 12°C / 22°F) Increase Outdoor air temp- erature min and max values to a difference greater than 22°F (12°C) Adjust setting to within appropriate range
255 CH setpoint minus ODR min water temperature was too small (min. 12°C / 22°F) Increase setpoint or decrease min water temD. Increase Outdoor water temperature min and max values to a difference greater than 22°F (12°C)
565 Heat exchanger T-rise limit was exceeded Heat exchanger temperature rise exceed Check for correct water flow