Lochinvar Knight Boiler Maintenance Checklist for Technicians

Lochinvar Knight boilers are crafted for high-efficiency hydronic heating performance. Like any hard-working unit, they need routine maintenance to keep running safely and reliably. A thorough inspection can help prevent poor combustion, heat exchanger problems and more. Use our Lochinvar Knight boiler maintenance checklist for technicians to ensure you’re hitting all the marks.

Quick Lochinvar Knight Boiler Maintenance Checklist

For fast reference, technicians should check:

• Boiler area and clearances
• Vent and air intake piping
• Condensate trap and drain
• System pressure and piping
• Expansion tank
• Relief valve
• Circulators
• Boiler water quality
• Burner condition
• Ignition electrode
• Flame sensor
• Ground wiring
• Control settings
• Error history
• Gas pressure
• Combustion readings
• Heat exchanger condition
• Startup operation

Lochinvar Knight Boiler Maintenance Checklist

When on a call for a Lochinvar unit, use this checklist as a general tech-friendly guide along with the specific service manual for the model you’re working on.

1. Review Reported Issues First

Start the service call by asking about recent symptoms. Some common clues will include:

• Intermittent lockouts
• No heat calls
• Unusual burner noise
• Condensate backups
• Pressure fluctuations
• Error codes on the display
• Delayed ignition
• Short cycling

2. Shut Down Power and Let the Boiler Cool

Before doing anything to the unit, make sure to disconnect the power and allow the unit to cool to avoid electric shock or burns. Please note that if there’s overheating occurring or the gas supply fails to turn off, don’t turn off or disconnect the power supply. Instead, shut off the gas at a location external to the appliance.

3. Inspect the Boiler Area

Take a look at the boiler. Make sure the area is clean, dry and free of any blockages that can interfere with combustion air, ventilation or the service access panel.

Check for:

• Combustible materials
• Gasoline or flammable vapors
• Corrosive contaminants
• Blocked air openings
• Water damage
• Signs of leaks
• Restricted service clearance

4. Check Venting and Combustion Air Piping

One of the most crucial parts on a high-efficiency boiler is the vent system. Inspect the vent as well as combustion air piping for:

• Proper support
• Sagging or separation
• Cracks or damage
• Loose fittings
• Obstructions at terminations
• Signs of condensate leakage
• Improper materials
• Evidence of recirculation

5. Clean and Inspect the Condensate System

Your condensate checklist should include:

• Remove and clean the condensate trap
• Check for debris or sludge
• Verify proper trap reassembly
• Confirm tubing is pitched correctly
• Inspect for cracks, leaks or restrictions
• Check condensate neutralizer media
• Test condensate pump operation if installed
• Verify drain termination is clear

6. Inspect Boiler Piping and System Pressure

Inspect this area for:

• Water leaks
• Corrosion
• Air in the system
• Improper pressure
• Failed or undersized expansion tank
• Faulty relief valve discharge
• Pump noise or vibration
• Poor flow conditions

7. Check Boiler Water Quality

If the water quality is poor, it can reduce heat transfer and promote corrosion in the heat exchanger. Lochinvar instructs that you thoroughly flush the system without the boiler connected to remove sediment.

For freeze protection, never use automotive antifreeze. It’s important to only use inhibited propylene glycol solutions that are formulated for hydronic systems.

8. Inspect the Burner, Flame Sensor and Ignition Electrode

Inspect the following:

• Dirty flame sensor
• Damaged electrode
• Incorrect electrode gap
• Cracked ceramic insulation
• Loose ignition cable
• Poor grounding
• Burner surface damage
• Debris in the combustion chamber

9. Inspect Wiring and Electrical Connections

After opening the access panels, inspect the following:

• Ignition wiring
• Flame sensor wiring
• Pump wiring
• Sensor connections
• Low-voltage terminals
• Ground connections
• Control board condition
• Fuse condition, if troubleshooting a no-display issue

10. Review Control Settings and Error History

Using the boiler display, review the following:

• Supply and return temperatures
• Outdoor reset settings
• DHW settings
• Pump delays
• Anti-cycling settings
• Cascade settings, if applicable
• Service notifications
• Error codes or lockout history

11. Perform Combustion Analysis

The Lochinvar Knight service manual includes a combustion analysis procedure as well as troubleshooting guidance for combustion levels. Make sure to verify the combustion readings and compare them to the acceptable ranges listed in the manual.

If the readings are off, make sure to check the venting, air intake, gas pressure, burner condition and combustion setup before making any adjustments.

12. Check Gas Supply and Pressure

Check the gas piping and confirm that the gas supply is properly sized and leak-free. Also, verify that the inlet gas pressure is under operating conditions per the manual.

13. Inspect the Heat Exchanger

Inspect for the following:

• Soot
• Debris
• Scaling
• Corrosion
• Condensate issues
• Signs of overheating

14. Perform Startup Checks

After reassembling the unit and restoring power and gas, run the boiler through a full operating cycle to confirm:

• Proper call for heat
• Pump operation
• Ignition sequence
• Flame stability
• Flame signal
• Supply and return temperatures
• Venting performance
• Condensate drainage
• No leaks
• No active faults