Adjusting the flame height on a gas fireplace sounds straightforward, but in New Zealand most of the controls involved are classified as restricted gasfitting work — meaning a licensed professional must carry them out. That said, there are a couple of things you can safely do yourself. This guide explains exactly where the line is, so you stay safe and legal.
What the Law Says About Gas Appliance Adjustments
In New Zealand, gas fitting work is regulated under the Gas Act 1992 and administered by the Plumbers, Gasfitters and Drainlayers Board (PGDB). Any work that involves adjusting, repairing, or modifying the gas components of an appliance — including burner pressure, gas valve settings, or air-to-gas ratios — is restricted work that must be performed by a licensed gasfitter. Doing this work yourself is illegal and could void your home insurance, invalidate your appliance warranty, and put your household at serious risk.
What a Homeowner CAN Safely Do
There are a small number of flame-related adjustments that are considered normal appliance operation rather than gasfitting work:
- Using the manual flame control knob or slider — Many gas fireplaces have a user-accessible knob, dial, or slider on the front or side of the unit that adjusts flame height within a pre-set safe range. This is designed for homeowner use.
- Using a remote control or wall thermostat — If your fireplace came with a remote or a wall-mounted controller, adjusting flame height via these controls is perfectly fine.
- Operating a smart home or app-based controller — Some modern gas fireplaces integrate with smart home systems; using these as intended by the manufacturer is acceptable.
If your fireplace has one of these controls and the flame simply isn't responding, check the batteries in the remote, ensure the pilot light is lit (see your owner's manual), and confirm the appliance is switched on at the wall.
Safety note: If you ever smell gas, hear an unusual hissing sound, or see a yellow or orange flame (rather than blue with yellow tips on decorative logs), do not attempt any adjustments. Turn off the appliance, ventilate the room, and call a licensed gasfitter or your gas retailer immediately. In an emergency, call 111.
What Requires a Licensed Gasfitter
The following adjustments must only be carried out by a licensed gasfitter:
- Adjusting the gas pressure regulator or burner orifice
- Changing the air shutter or air-to-gas mixture settings
- Modifying or replacing the gas valve, pilot assembly, or thermopile/thermocouple
- Altering the maximum or minimum flame height stops on the valve
- Converting the appliance between natural gas and LPG
- Any internal component adjustment covered in the service manual
These tasks require specialist tools, gas pressure gauges, and a thorough understanding of combustion safety. Getting them wrong can result in carbon monoxide poisoning, fire, or explosion.
Common Reasons Your Flame Height May Have Changed
If your flame seems lower or higher than usual and you haven't changed any settings, there are a few possible causes worth knowing about:
| Possible Cause | Who Fixes It |
|---|---|
| Dirty burner or blocked ports | Licensed gasfitter (annual service) |
| Low gas supply pressure | Gas retailer or licensed gasfitter |
| Faulty gas valve | Licensed gasfitter |
| Thermocouple or thermopile failure | Licensed gasfitter |
| Remote/receiver battery flat | Homeowner |
| Thermostat set too low | Homeowner |
Annual servicing by a licensed gasfitter is the best way to keep your fireplace performing correctly and safely. Regular maintenance of gas appliances is recommended to prevent carbon monoxide risks — particularly important in well-insulated homes built to meet the NZ Building Code or Healthy Homes standards.
Checking Your Owner's Manual First
Before doing anything, locate your fireplace's owner's manual. This will clearly show which controls are intended for homeowner use and which are service-only. If you've lost the manual, search the manufacturer's name and model number online — most brands publish PDFs on their websites. Your installer or a local gasfitter may also have access to technical documentation.
How to Find a Licensed Gasfitter
Always verify that anyone working on your gas fireplace holds a current gasfitting licence. You can check a tradesperson's registration on the PGDB website. A licensed gasfitter will issue you a Certificate of Compliance for any restricted work carried out — keep this with your home records.
When to Call a Professional
Call a licensed gasfitter if:
- The flame height has changed noticeably without you adjusting anything
- The flame is yellow, orange, or very sooty
- The appliance is making unusual sounds
- The pilot light won't stay lit
- You want to adjust anything beyond the basic user controls
- The fireplace hasn't been serviced in the past 12 months
You can find qualified, local gasfitters in your area right here on tradedirectory.co.nz — look for tradespeople who list gas fireplace servicing and check their PGDB registration before booking.
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