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What's Included in a Professional Boiler Service?

By Ace Plumbing Team5 December 20254 min read

A professional boiler service is like an MOT for your heating system. It's a thorough inspection, test, and clean carried out by a Gas Safe registered engineer. Here's exactly what we do during a standard service at Ace Plumbing.

The Inspection (Visual Checks)

First, your engineer will carry out a visual inspection of the boiler, flue, and surrounding area. They're looking for:

  • Signs of corrosion or leaks around the boiler casing
  • Correct flue termination and sealing (especially important for carbon monoxide safety)
  • Adequate ventilation around the boiler
  • Condition of electrical connections
  • General cleanliness and accessibility

Gas Checks

Your engineer will test the gas supply to the boiler, checking:

  • Gas pressure at the meter and at the boiler
  • Gas flow rate to ensure the boiler is receiving the correct supply
  • Inspection of gas connections for leaks using leak detection fluid

Combustion Analysis

This is one of the most important parts of the service. Using a flue gas analyser, your engineer measures:

  • CO (carbon monoxide) levels in the flue
  • CO₂ levels to check combustion efficiency
  • Flue gas temperature
  • The ratio of CO to CO₂ (the combustion ratio)

This data tells the engineer whether the boiler is burning gas safely and efficiently. Any readings outside normal parameters indicate a problem that needs addressing.

Cleaning

The engineer will clean key components including:

  • The heat exchanger (the core of the boiler)
  • The burner assembly
  • The condensate trap (on condensing boilers)
  • The ignition electrode

Cleaning these components improves efficiency and prevents breakdowns.

Safety Device Testing

All safety devices are tested to ensure they work correctly:

  • Overheat thermostat
  • Flame sensor / ionisation probe
  • Pressure relief valve
  • Expansion vessel pressure check

The Certificate

After the service, your engineer provides a service record and Gas Safe certificate. Keep this safe — you'll need it for your manufacturer warranty and if you sell your property.

How Long Does It Take?

A standard boiler service takes 30-60 minutes depending on the boiler type and any issues found.

Book your annual boiler service today. Call Ace Plumbing on 01908 555 888.

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