Gas Boiler System Commissioning Checklist: A Comprehensive Guide

A comprehensive Gas Boiler System Commissioning Checklist is crucial to ensure the safe and efficient operation of a gas boiler. This detailed guide covers the key steps involved in the commissioning process, providing technical specifications and a DIY approach for homeowners.

Cleanse the System

Before starting the commissioning process, it is essential to flush the system thoroughly to remove any debris and prevent black magnetite (sludge) from flowing through the heat exchanger. This can be done by:

Flushing the system with a suitable chemical cleaner, such as a phosphate-free, biodegradable cleaner, to remove any accumulated sludge or scale.
Ensuring the system is completely drained and refilled with clean water, repeating the process until the water runs clear.
Checking the system’s pH level, which should be between 7.0 and 8.5 for optimal performance.

Add a Corrosion Inhibitor and Refill

After cleaning the system, a corrosion inhibitor should be added to protect the radiators and prevent the formation of hydrogen gas within the system. The recommended dosage of corrosion inhibitor is typically 1 liter per 100 liters of system volume, but it’s essential to follow the manufacturer’s instructions.

Test the Gas Flue Analyser

Conducting a flue gas analysis is crucial to ensure the boiler is burning gas correctly and safely. This test checks the boiler’s efficiency, combustion quality, and emissions, including:

Carbon monoxide (CO) levels, which should be less than 335 ppm (parts per million) for natural gas and 570 ppm for LPG.
Carbon dioxide (CO2) levels, which should be between 8.5% and 10% for natural gas and 9.5% and 11% for LPG.
Oxygen (O2) levels, which should be between 3% and 6% for natural gas and 4% and 7% for LPG.

Gas Rating and Tightness Test

The gas supply pressure and pipe diameter must be checked to prevent leaks and ensure smooth operation. This includes:

Verifying the gas supply pressure is within the manufacturer’s recommended range, typically between 18 and 22 mbar for natural gas and 37 mbar for LPG.
Ensuring the gas pipe diameter is correctly sized to deliver the required gas flow rate, typically 22 mm for natural gas and 15 mm for LPG.

Adjust Boiler Output

The boiler output should be set to the correct size for the house and number of radiators to ensure energy efficiency and proper heating. This can be done by:

Calculating the total heat loss of the property, taking into account factors such as the building’s size, insulation, and number of rooms.
Selecting a boiler with a suitable output capacity, typically ranging from 12 kW to 35 kW for most residential properties.
Adjusting the boiler’s output settings to match the calculated heat loss, ensuring the boiler is not oversized or undersized.

Let-by and Gas Tightness Test

The gas pressure inside the pipework must be checked to ensure it holds the right amount of pressure and prevent leaks. This involves:

Performing a let-by test to check for any gas leaks in the pipework, which should not exceed 2 mbar per minute.
Conducting a gas tightness test to verify the integrity of the gas supply system, which should not exceed 0.1 mbar per minute.

Register Guarantee and Explain Operation

After the commissioning process is complete, the boiler’s guarantee should be registered, and the customer should be provided with a detailed explanation of the boiler’s controls and necessary regular maintenance. This includes:

Registering the boiler’s guarantee with the manufacturer, ensuring the customer can benefit from any warranty coverage.
Demonstrating the boiler’s controls, including how to adjust the temperature, set the timer, and perform basic troubleshooting.
Advising the customer on the recommended maintenance schedule, such as annual servicing and cleaning, to maintain the boiler’s efficiency and safety.

Safety Checks and Tests

Throughout the commissioning process, it is crucial to verify the integrity of the boiler’s components, ensure proper fuel supply and ventilation, and check all safety devices. This includes:

Inspecting the boiler’s components, such as the heat exchanger, burner, and controls, for any signs of damage or wear.
Verifying the boiler’s ventilation system is functioning correctly, with adequate air supply and flue gas exhaust.
Checking the operation of safety devices, such as flame supervision devices and low water pressure sensors, to ensure they are working correctly.

Performance Tests

Functional tests should be conducted to verify the proper operation of the boiler, including:

Ignition test: Ensuring the boiler ignites correctly and the flame supervision device is working properly.
Burner operation test: Checking the burner’s performance at different firing rates, including low and high fire.
Gas working and standing pressure test: Verifying the gas pressure is within the manufacturer’s specified range during both operation and standby.

Commissioning Report

Finally, a comprehensive commissioning report should be prepared, documenting the entire process, including any adjustments, test results, and safety checks. This report should be provided to the customer and kept for future reference.

Technical Specification of Gas Boiler System Commissioning Checklist

Boiler Installation/Commissioning Checklist Template:
– Includes company/installer details, client/landlord details, job address, appliance details, safety checks, combustion readings, gas checks, engineer comments, and signatures.
– Typically a 2-4 page document that covers all the essential information required for the commissioning process.

Gas Safety Checks:
– Ensure the boiler complies with all necessary regulatory requirements, such as the Gas Safety (Installation and Use) Regulations 1998 in the UK.
– Verify the boiler meets the manufacturer’s specifications, including the presence of flame supervision devices and low water pressure sensors.

Performance and Efficiency:
– Conduct flue gas analysis to measure the boiler’s efficiency, with a target efficiency of at least 90% for modern condensing boilers.
– Ensure the boiler’s combustion quality and emissions are within the acceptable limits set by regulatory bodies.

Safety Devices and Interlocks:
– Check the integrity and proper functioning of safety devices, such as flame supervision devices and low water pressure sensors, to prevent unsafe operation.
– Verify the boiler’s safety interlocks, which automatically shut off the gas supply in the event of a fault or unsafe condition.

DIY Gas Boiler System Commissioning Checklist

While it is recommended to have a Gas Safe registered engineer perform the commissioning, homeowners can undertake some basic steps:

Ensure Proper Installation:
Verify that the boiler installation meets all applicable regulations, standards, and manufacturer requirements, such as correct clearances, ventilation, and gas supply.
Check that the boiler is securely mounted and the condensate drain is properly connected.
Clean and Prepare the System:
Clean the system according to the manufacturer’s instructions, using a suitable chemical cleaner to remove any debris or sludge.
Add the recommended dosage of corrosion inhibitor to protect the system components.
Conduct Basic Safety Checks:
Check for any gas leaks, loose connections, or potential issues that could affect the boiler’s safe operation.
Ensure the boiler’s safety devices, such as the flame supervision device and low water pressure sensor, are functioning correctly.

Remember, while these DIY steps can help ensure the basic safety and operation of the gas boiler system, it is always recommended to have a qualified Gas Safe registered engineer perform the full commissioning process to ensure the system is operating safely and efficiently.