15 Mar 2025

3 Reasons for CO Leaks in Gas Heaters and How to Prevent them

Focus on Brands: Ferroli, Rinnai, Paloma, and Macro

Common Causes of CO Leaks in Gas Heaters

Based on years of repair insights from brands like Ferroli, Rinnai, Paloma, and Macro, the primary culprits of CO leaks include:

1. Heat Exchanger Leaks Leading to Incomplete Combustion

How It Happens: Water leakage from the heat exchanger drips onto the burner. As the water evaporates, minerals (e.g., calcium) accumulate and block gas orifices. This disrupts the air-to-gas ratio, causing incomplete combustion.
Severity: Even minor blockages reduce combustion efficiency by 10–20%, increasing CO emissions. Severe blockages may spike CO levels beyond safe thresholds.

2. Physical Damage to Gas Components

Gas pipe unions or valves near the heater (e.g., in HDB utility cabinets) are vulnerable to accidental damage during renovations or servicing. For instance, drilling into concealed gas pipes during kitchen renovations—as seen in the 1992 Ballota Park Condo incident, which tragically claimed a teenager’s life—can cause catastrophic leaks.

3. Unlicensed Repairs and Corroded Parts

Unlicensed handymen often skip mandatory safety checks, such as the gas soundness test (per SS 608:2015+A3:2023 Code of Practice), which requires using a U-gauge to maintain 300mm water pressure for 5 minutes. Reusing corroded gas valves after dismantling may also compromise seals, leading to gradual leaks.

Understanding Town Gas Composition and Risks

Singapore’s sole gas supplier, City Energy, distributes town gas with the following composition range:

Hydrogen: 41.0–65.0%
Methane: 4.0–33.0%
Carbon Monoxide (CO): 2.0–6.0%

Note: While town gas inherently contains CO, incomplete combustion from faulty heaters adds more CO to the environment, escalating risks.

Ventilation: A Critical Yet Overlooked Factor

Under SS 608:2015+A3:2023, instantaneous gas heaters rated ≤42.2 MJ/h installed in well-ventilated kitchens do not require flues. However, many Singaporeans keep kitchen windows shut to guard against rain, trapping toxic gases indoors. Heaters exceeding this rating must be installed outdoors (e.g., aircon ledges), but improper placement or blocked vents indoors can still pose risks.

Why Licensed Gas Service Workers (LGSW) Matter

The Energy Market Authority (EMA) mandates that only licensed gas service workers handle installations and repairs. Here’s why:

Compliance with SS 608: Licensed professionals conduct gas soundness tests, verify ventilation, and use certified parts.
Preventing Catastrophes: The Ballota Park incident underscores the dangers of unchecked gas leaks. Licensed workers identify risks like corroded valves or concealed pipe damage.
Accountability: EMA-licensed workers carry insurance and adhere to safety protocols, unlike unregulated handymen.

The Risks of Cheap Fixes: Saving 50–50–100 with unlicensed repairs risks voiding warranties, legal liabilities, or worse—fatal leaks.

What to Do If You Suspect a Gas Leak

Evacuate the area immediately.
Call City Energy’s 24/7 Emergency Line: 1800 752 1800.
SP Group technicians will arrive to test for leaks. If confirmed, they will shut off the gas supply and advise engaging an LGSW to rectify the issue.

Prevention Tips for Singapore Households

Annual Servicing: Engage EMA-licensed technicians, especially for heaters over 5 years old.
Post-Renovation Checks: After kitchen renovations, insist on a gas soundness test to rule out pipe damage.
Ventilation Discipline: Keep kitchen windows open when using the heater, even during rain. Use window shields instead.
CO Detectors: Install them near heaters and bedrooms; replace batteries yearly.

Final Advice

While brands like Rinnai and Paloma are engineered for safety, even robust systems fail without proper care. CO risks are preventable—prioritise safety over short-term savings. To find licensed gas workers, visit the EMA directory or check the SP Utilities app.

Stay vigilant, stay safe. A small leak today could become a tragedy tomorrow.