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When gas hot water stops, the cause is usually one of a handful of things — and a couple are safe to check yourself before calling a gasfitter. The right checks depend on whether you have an older gas storage cylinder with a pilot light or a modern califont (continuous flow) unit. Here is how to work through it.
First, Which Do You Have?
- Gas storage cylinder — a tank heated by a gas burner, often outside, usually with a pilot light on older models.
- Califont / continuous flow — a compact wall-mounted unit that heats water on demand as it flows, with electronic ignition rather than a standing pilot.
Gas Storage Cylinder With a Pilot Light
- Check the pilot is lit. On older units a small pilot flame stays burning. If it has gone out, you can usually relight it following the instructions printed on the unit.
- Check the gas supply. Make sure the gas is turned on, and if you are on LPG, that the bottle is not empty and is switched over.
- If the pilot will not stay lit after relighting, the thermocouple (the safety device that senses the pilot flame) or another component may have failed. This is a gasfitter job — do not keep trying.
Califont / Continuous Flow Unit
- Check power and gas. Califonts need electrical power for ignition and controls, plus gas supply or a full LPG bottle. A tripped switch or empty bottle is a common cause.
- Look for an error code. Most units display a fault code on the wall controller. Note it down — it tells the gasfitter exactly what is going on.
- Check water flow. Continuous flow units need a minimum flow rate to fire up. A partly closed isolation valve, a blocked inlet filter, or very low pressure can stop them igniting.
- Listen for ignition. If you hear it trying to ignite but not firing, or it fires then cuts out, note what happens — that helps with diagnosis.
When to Stop and Call a Gasfitter
Call a registered gasfitter if the pilot will not stay lit, the califont shows a fault code or will not ignite, you smell gas at any point, or you simply cannot get it going. Gas work must be done by a registered gasfitter — see what to do if you smell gas if you ever notice a gas smell. For a complete walk-through of all hot water types, see no hot water? a step-by-step troubleshooting guide.
Gas Hot Water Repairs Across Auckland
Water and Gas Worx are registered gasfitters who repair gas hot water — storage and continuous flow — across Auckland. Lost hot water? Our emergency service is available 24/7. See our hot water services and areas we service.
Call 0800 322 322 or email [email protected].
Frequently Asked Questions
Why does my gas hot water pilot light keep going out?
A pilot that will not stay lit most often points to a failing thermocouple — the safety device that senses the pilot flame and shuts off the gas if it goes out. It can also be a draught or a dirty pilot assembly. If relighting does not hold, it needs a registered gasfitter rather than repeated attempts.
What does an error code on my califont mean?
Continuous flow units show fault codes to indicate the problem — ignition failure, flow issues, overheating and so on. The code itself is useful: note it down and tell the gasfitter, as it points straight to the likely cause and speeds up the repair.
Can I relight my gas hot water myself?
On many older gas storage units you can relight the pilot following the printed instructions on the unit. If it will not light or stay lit, or you smell gas, stop and call a registered gasfitter. Never attempt internal repairs on a gas appliance yourself — gas work must be done by a registered gasfitter.
How much does a gas hot water repair cost?
It depends on the fault and parts needed, so we quote before starting. Our rate is $155 plus GST for the first hour, then $100 plus GST per hour after that. After-hours is $295 plus GST for the first hour, and public holidays $395 plus GST for the first hour, then $100 plus GST per hour after that.