Losing hot water is disruptive and usually urgent. The first thing to know is that a gas water heater and an electric water heater fail for different reasons, so the checks differ. Some are simple things a homeowner can safely reset; others need a licensed technician. This guide walks through both types and separates the easy fixes from the ones that need a pro.
First: Is Your Water Heater Gas or Electric?
Look at the unit. A gas water heater has a burner at the bottom, a gas line, and a vent pipe on top. An electric water heater has an electrical cable running to it and no burner or vent. This determines what to check.
No Hot Water from a Gas Water Heater
Pilot light or igniter out
The most common cause. If the pilot light is out, the burner cannot fire. Modern units use an electronic igniter instead of a standing pilot. Check for a lit pilot through the sight glass, and follow the relight instructions on the label if it is out.
Failed thermocouple
The thermocouple senses the pilot flame and keeps the gas valve open. When it fails, the pilot will not stay lit. This is a common, inexpensive part replacement.
Gas supply interrupted
Confirm the gas shut-off valve is open and other gas appliances work. If no gas appliance works, call Enbridge at 1-866-763-5427.
Faulty gas control valve
If the pilot lights but the burner never fires, the gas valve or thermostat control may have failed, which needs a technician.
No Hot Water from an Electric Water Heater
Tripped breaker
Electric water heaters draw a lot of power. Check the electrical panel and reset a tripped water-heater breaker once. If it trips again, stop and call a technician.
Tripped high-limit reset
There is a red reset button on the upper thermostat behind the access panel. If it has tripped, pressing it once can restore heat. If it trips again, an element or thermostat has failed.
Failed heating element
Electric units have two elements. A failed upper element means no hot water; a failed lower element means hot water that runs out fast. Elements are a common replacement.
Failed thermostat
A failed upper or lower thermostat stops the elements from heating and needs replacing.
Hot Water Runs Out Too Fast or Is Only Lukewarm
If you get some hot water but it runs out quickly or never gets hot enough, the usual causes are a failed lower heating element (electric), a thermostat set too low, sediment buildup in the tank reducing capacity, or a tank that is simply undersized for the household. A tankless unit that runs cold in winter is usually undersized for the cold inlet water.
What to Check Yourself
- Confirm the thermostat setting on the unit is at a safe hot setting (around 49 to 60C).
- For gas: check that the pilot or igniter is working and the gas valve is open.
- For electric: reset a tripped breaker once, and check the red high-limit reset button behind the upper panel.
- Check for leaks around the base; a leaking tank needs replacement, not repair.
- If nothing restores hot water, call a licensed technician.
When to Call a Technician
Call EcoFrost if the pilot will not stay lit, a breaker keeps tripping, you suspect a failed element or thermostat, the tank is leaking, or you smell gas. Water heater repairs involving gas or electrical components need a licensed technician. We service and replace gas, electric, and tankless water heaters across the GTA, same day, with no overtime fees.
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Book Water Heater Repair?Frequently Asked Questions
Why is my water heater not working all of a sudden?
Why do I have no hot water but the tank is on?
Why does my hot water run out so fast?
Can I fix a water heater myself?
How much does water heater repair cost in Ontario?
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