What to Do When Your Hot Water Runs Cold

20 July 2020


Disaster strikes. Your hot water system has given up the ghost during the morning shower rush. Or it’s failed on a Friday night, right as you wanted to run a relaxing bath.

What do you do? What do you even need to look for? Well the solution may be staring at you right in the face. Simple solutions like the gas or electricity supply switching off are generally a quick fix. Likewise, maybe all you need to do is readjust the thermostat.

Or you could be like my mum when I was younger. She called a plumber, and while we waited boiled water in a kettle over and over again just to fill up a bathtub. Yeah, I wouldn’t have the patience to do that myself!

If you’re after some clear answers now, you’re in luck. Read on to find out what to do when your hot water goes out.

Why Is My Hot Water Not Working?

The first thing you’ll want to know is why is my hot water not working. Unfortunately there’s no answer to cover all the bases. The reason could be different for a gas or electric hot water heater. Luckily the most common causes are typically easy to spot and that’s what the next few sections will help you uncover.

Gas Hot Water Systems

Smells like A Gas Leak

This is potentially the most serious concern, and it’s important to mention it first. If your hot water has suddenly gone cold and you smell something funky while investigating, you might have found a gas leak.

We all know the trademark smell of gas – kind of like rotten eggs. It’s the last thing you want get a whiff of. In the most serious outcome, it could be the last thing you smell.

At the first indication of a gas leak, if you can turn off the gas supply. Then call in an expert gas fitter or technician.

The Pilot Light Keeps Going Out

Now, it’s not all doom and gloom. It could just be your pilot light. As the ignition source for your boiler, when it’s not working you’re not going to have any heat.

Having said to turn off the gas supply in case of an emergency, the opposite might apply here. Is the gas on, or is the gas valve on the hot water unit off? All that’s required is switching it back on, and igniting the pilot flame – although make sure first the gas isn’t off for a serious reason.

You want a nice, hot flame for a consistent hot water supply. Dust and debris can impact its efficiency or cause a blockage. It’s always important to maintain a clean space around the water heater and the flue. Your flue removes dangerous chemicals such as carbon monoxide. As a result it can get pretty messy, which is no fun to clean, but necessary.

Another reason your pilot light is struggling is the thermocouple, a sensor which measures the temperature of the flame. Any weakness in the heat and it could switch off and not communicate to the boiler properly.

So, give the area surrounding your boiler or wall unit a nice clean, check that the pilot light has a clean home, and then go through the steps to reignite it. Depending on the age of the unit that could vary with an electric or gas ignition switch.

Electric Hot Water Systems

The Power’s Not On

Do you have an electric boiler instead of gas? When something goes wrong, head to the switchboard first. The system may have overloaded, blowing a fuse. Hot water systems should be on their own circuit, also, so when the safety switch triggers the rest of your home is unaffected. Switch the fuse back on and often you’re good to go.

However, if it’s a recurring problem don’t get stuck in repeating the short term fix. There’s probably something wrong with the wiring.

Some people will be confident with DIY wiring. I for one, prefer calling in an electrician. The most important consideration, if you are going to check for any loose wires, is make sure you do turn off the power supply first. Then you can safely fiddle with wires or clean out any internal heating elements. Keep in mind that work not done by a qualified electrician will void any warranties. 

Faulty Thermostat

The thermostat controls your water temperature. Hot water not hot? Blame a faulty thermostat. The issue could be as simple as an incorrect setting, or a defective thermostat requiring replacement. Either way, it’s not a serious issue that will have you forking out too much cash.

Common Concerns

Water Leaks and Poor Supply

Regardless of the system, you may have sprung a leak. And you should notice because there’ll be water everywhere. A leaking tank unfortunately requires a full replacement, which is a tough pill to swallow at times. But it’s not safe to patch it up with duct tape and call it a job done. The tank needs to be perfect for your safety.

Alternatively, the leak is in the pipes. That’s typically a simpler fix. You may be able to replace the piping yourself, and feel proud about some confident DIY! Just make sure you do it right so there’s no unwanted waterworks at 3am.

Or, the issue might just be too little water for too many people. An instantaneous or wall mounted system can’t always meet the demands of a large household. Even a boiler tank could struggle with the morning rush as families increase from 2-3 people, to 4-5. Then it’s time for an upgrade.

Old age

Sometimes you just have to acknowledge the hard truth. Your boiler’s done its dash. Even the likes of Michael Jordon had to call it a day. Like MJ, you can expect to get about 15 years’ service out of a hot water system, on average. Some will last closer to 10, others 20 if maintained well.

And while you can keep repairing and patching, after 10 years you should be aware that updating to a new heater altogether will save you money. Newer models are more efficient, giving more bang for your buck!

So, What Should I Do With My Hot Water?

You’ve found the problem and have hopefully been able to fix it! But if it’s turned out to be more serious, it’s probably time to call in a Metropolitan Plumbing professional, electrician or gas fitter. And there’s no shame in that.

Hopefully, though, you’ve learnt a thing or two and know you won’t have to grab a kettle the next time you want a bubble bath and the hot water’s gone out.



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