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No Hot Water? | Troubleshooting tips & tricks for hot water cylinders and continuous flow hot units

Updated: Dec 14, 2021

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Troubleshooting No Hot Water - Common Hot Water Cylinder Problems and Faults

We agree, there’s no better way to start the day than with a hot refreshing shower! Waking up to find you have no hot water can be a massive drag. This hot water cylinder troubleshooting guide will walk you through common problems that could cause your hot water cylinder to stop working.

Why is your hot water cylinder cold?

Hot water cylinders Generally have a lifespan of approximately 10 years on average, with that being said we often come across hot water units that have been running perfectly for over 20 years and some that have started faulting in as little as 5-7 years. There are a number of reasons which influence the lifespan of a hot water heater such as Water Quality, acidity, location the unit is installed (indoor or outdoor), Material – Enamel or stainless steel tank, water pressure and the list goes on...

If your hot water cylinder is not functioning as it should Don’t Panic! And read on…

Here are some of the most common hot water cylinder problems we come across on the daily, including simple yet effective ways to remedy or contain the problem to avoid further damage to your home or property until a professional can get there.

· No hot water

· Low water pressure

· Strange Noises or sudden Banging

· Bad Smells

· Low Temperature

· Temperature Fluctuations

· Running out of hot water

· Long wait time for hot water to reach the taps

· High Power Bill

· Gas califont problems

· Hot water cylinder thermostat problems

· Leaking Hot water Cylinder

· Relief Valves Running Frequently

· Rusty Hot water Cylinder

· Hot water Temperature

· Fluctuating Temperature

· Fluctuating Pressure

No hot water – what to check? Hot water cylinder troubleshooting

Does cold water flow through your taps but you have ‘no hot water’ ?

1. Check The power isolator switch beside the cylinder is turned to the ‘On’ position.

2. Check the electrical switchboard of your home to see if the circuit breaker marked “hot water” or “HWC” is turned on.

3. Check the outside meter box to see if any hot water circuit breaker or switch is turned off.

4. Call your power company and ask if there are any hot water line faults or if you are set up on ripple control – if this is the case your power provider can disconnect your hot water cylinder from the grid during peak hours.

5. Call a local electrician or plumber with a limited electrical license as there could be a fault with the electrical power supply, element and/or a thermostat issue.

Does water flow from the cold tap but not the hot tap?

1.) Check to see if the cold-water valve to the cylinder is turned on.

2.) Call a local plumbing as this may be a plumbing - malfunctioning valve issue.

No water Flowing from your taps?

1.) Check if the water main valve is turned on – This controls the supply of water to your home and is generally located on the outskirts of your property, at the end of your driveway or fence line.

2.) Check if your neighbours have water, there could be a network fault affecting the area.

3.) Call your water supply authority.

No hot water – Instant water heaters or continuous flow hot water units troubleshooting

1.) Check the power switch beside the unit is turned on. (switch usually mounted on an external wall)

2.) Does the unit have power running to it? If your unit is not ‘hard wired’ and has an external power socket you can easily test the power source by simply unplugging the unit and plugging in any other household appliance.

3.) Check the digital temperature controller is turned ‘on’ (if fitted).

4.) Is the unit itself displaying an error code, this can be referenced using the error codes included below.

5.) The unit may be failing to automatically ignite and may need to be manually reset. Please follow these instructions:

1. Turn a hot water tap on, leave it running and head outside.

2. Turn the water inlet valve off/shut (this is the valve that supplies the cold water to the unit, if you look underneath the unit at the bottom panel you will see which pipe is the “cold” pipe)

3. Switch the power point off and wait five seconds.

4. After five seconds, turn the power point back on and open/release the water valve.

5. Your hot water unit should now be operational again.

If problems persist please call us on 0508 367 468 . We also advise that you contact your local gasfitter and ask for an “Automatic Changeover Kit” to be installed and this should prevent this problem from happening in the future.

6.) Check Gas supply is turned ‘on’.

7.) If you are on LPG gas Bottles, here's how you can easily check your gas levels:

1. Use a jug of hot tap water from your home - More is better.

2. SLOWLY pour the hot water down one side of the gas bottle.

3. A line of condensation may appear, indicating the gas level. If not:

4. Wait a few seconds and then run your hand down the same side of the gas bottle, where you poured the water.

5. You should feel a change of temperature at the level of the gas.

6. If you feel no difference, the gas bottle is likely empty.

8.) If there is water flowing through the hot and cold tap check and clean the screw out filter on the cold water inlet.

9.) If there is not water at both the hot and cold taps check if the water is turned ‘on’ at your water main line.

10.) Check if your neighbours have water at their taps.

11.) Check with your water supplier as there may be a network fault

12.) Call a local plumber or gas fitter as this may be a plumbing issue or your hot water unit may have reached the end of its life.

No hot water - who to call?

If all else Fails, our friendly staff will be happy to help with the rest.

Contact us Today 0508 367 468 or email us at

24/7 - 365.

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