Why Is My Hot Water Not Working?

No Hot Water or Hot Water Not Working Well Enough?

Running out of hot water is a crisis in any household. Before you call a plumber it is a great idea to check a few simple things first. This could get your hot water back on quickly and save you a call out fee.

Hot Water Infographic
Hot Water Infographic

Step 1: What Is The Water Flow Like?

Check how much water is flowing out of the hot water tap. Is this the normal volume of water or is it flowing less than you would expect?

No Flow
This tells you that the problem isn’t your hot water system. It is more likely to be a blocked pipe or a stuck washer. If you are confident you can go ahead and change the washer. If you have a blocked pipe you should call a plumber because it’s likely you’ll need some help to solve that.

Some Flow But Not Enough
If you have some flow, but not as much as you need, your next question is what sort of hot water system do you have? Once you know that you can follow the next few plumbing detective steps.

Step 2: Is It A Storage Tank Or Instant Hot Water System?

Do you have a storage tank or an instant flow hot water system? It’s easy to tell the difference. One system has a big cylinder and the other is a smaller rectangle unit that is wall mounted. (See the illustration below.)

Step 3: If It's A Storage System, Is It Gas or Electric?

Next question: Is it gas or electric? Usually you’ll know by the bills you pay. With gas systems, you may hear the gas unit kicking in. Electric hot water units make very little sound.

Follow our Checklist to decide what to do next.

Storage Tank Hot Water System Issues

Thermann Reece Hot Water Unit Systems

Gas Hot Water Storage Troubleshooting

Once you have identified that you have a gas storage unit hot water system there are a few things you can check.

Pilot Light
Is the pilot light on? If you’ve had very windy weather, a pilot light can blow out.  If you discover that the pilot light has gone out, follow the instructions inside the unit to re-light the pilot light. If it is difficult to open or make sense of, you might need to call a plumber.

Water At Base
Is there water around the base of the hot water system? This is usually a sign that the hot water system has reached its use-by date. They generally last 10-15 years, depending on the brand and level of use. Water on the ground could indicate that the unit has split and needs replacing. You’ll need a plumber for that.

PTR Valve Check
If the pilot light is working and the thermostat setting is correct, try pulling the PTR valve. This is described in your hot water system manual. If the hot water exists in this pipe then your tempering valve may need replacing and your plumber can assist with that.

Electric Hot Water Storage Troubleshooting

Circuit Breaker
Check that the circuit breaker for the hot water unit is on. This is in your main switchboard.

If you’ve moved house, maybe the circuit breaker is switched off. Check that it is safe to turn on. Once turned on, wait one hour and then check the hot water situation again.

Water At Base
Is there water around the base of the electric hot water system? This is usually a sign that the hot water system has split. Depending on the brand and level of use, you might see this after 10-15 years of use. You’ll need a plumber to install a new hot water system for you.

Wall Mounted Hot Water System Troubleshooting

Rinnai Infinity Continuous Flow Hot Water System

Instant Flow Hot Water Troubleshooting

Check that the power to the unit is switched on.

Check that that gas and hot water valves are both switched on.

Pilot Light
Older units have a pilot light. If this has gone out, read the instructions and relight. If it is too difficult to open the unit or read the old instructions, you’ll need to call a plumber for assistance.

If your power is on and the valves are on and you still have no hot water, it is possible the hot water system will need to be replaced. So you’ll need to call your plumber.