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Hot Water Not Working? We Answer Your Common Questions

Nothing is more frustrating than a hot water system that’s not working. Dishes covered in leftovers are just building up in the sink, while the kids are complaining about a frosty shower.

Now, the best thing to do in any scenario is to call a local plumber. But sometimes you just want to try and fix the issue yourself, and that’s certainly possible! You just need to know what exactly you’re looking for.

To help, Jim’s Plumbing is answering your most frequently asked questions about hot water systems that have stopped working.

Why does the Pilot Light Keep Going Out?

First up, your gas hot water system may or may not have a pilot light, depending on the age or model. Many newer instantaneous units have electronic ignition, with a gas burner only.

Regardless, if your system does have a pilot light, also known as a pilot flame, it may be going out due to the following issues:

Damaged Thermocouple 

A faulty thermocouple either needs to be cleaned or replaced. The thermocouple is a wire-like probe that sits in the pilot flame, acting as a safety device that is triggered when the flame does go out. It shuts the gas valve when the pilot light does go out.

Faulty Thermostat

The thermostat regulates temperature within a hot water system. Also known as a unitrol or sit-valve, if it fails then your flame is not regulated properly.

Clogged Pipework

Any blockage within the gas pipeline could cause your flame to flicker or go out completely. There are small particles (soot, debris or dust) that can float inside the pilot tube, blocking the flame. It should be cleaned annually during a gas hot water service.

Why is my Shower Going from Hot to Cold?

There are a few reasons why your water’s going from hot to cold without rhyme or reason. The most likely ones include:

Supply Can’t Meet Demand

Whether it’s a storage tank or continuous flow system, your water heater might just not be keeping up with the demand. A busy household where people use multiple outlets at once requires a hot water unit that can supply a steady flow of hot water. 

For example, a 160 litre storage tank would be stretched to its limit in a four-person home.  Meanwhile, a 20 litre gas continuous flow water heater would not quite be enough on its own for a busy family of six.

Faulty Thermostat

If the thermostat isn’t set to the right temperature or is faulty, then it’s going to directly impact your hot water. The water coming out may be far too low, offering lukewarm or fluctuating showers.

Malfunctioning Valves

There are several valves involved in delivering hot water to your home. A tempering valve controls the mixture of hot and cold water that is sent through to your hot water taps. 

If it’s set incorrectly there’s a chance you may receive a burst of cold water with each cycle of water, rather than a balanced output. Valves can also become clogged or damaged, impacting the delivery.

My Circuit Breaker Keeps Tripping, is this a Hot Water Issue?

Hot water systems should always be on their own individual circuit to ensure any electrical or wiring issues are isolated to the water heater. That way, when anything trips or a fuse blows, it’s easy for an electrician to investigate.

In terms of hot water electrical faults, often the problem is as simple as a faulty circuit breaker. Your local electrician can replace this, or provide switchboard maintenance in case the problem is slightly more serious.

Meanwhile, it could also be a faulty electrical element within the water heater. If the wiring is damaged then it may be overloading the circuit, causing the circuit breaker to trip. 

Why is Water Leaking From my Hot Water System?

There are a few places where water can leak from a hot water system, and some are certainly better than others.

One of the more common locations of a leak is the temperature pressure relief valve. Located near the top of a water heater, it’s used to help alleviate the internal pressure of a storage tank. If it is leaking, even slowly, that means it needs to be lifted up so that hot water can be discharged.

A continuous leak is not good, though, as it means there is either too much pressure inside or the valve is faulty. In both cases, contact a licensed plumber.

It’s also possible for associated pipework to spring a leak as fittings or fixtures fail.

The one place you don’t want a leak is from the cylinder itself. This means the unit is damaged and could easily be a major disaster if large amounts of water start flowing. Unfortunately, it also means that your hot water system will have to be replaced.

Regardless of where the leak is, contact your local plumber and shut off your water supply or isolation valve while you wait.

What do I do if Water is Leaking from my Ceiling?

A leaking roof may or may not be linked to your hot water system. If it’s a ground mounted unit, you probably have another issue, such as a hole in the roof. That certainly requires fast attention but isn’t something you can blame on a water heater.

However, if you have an old gravity fed unit or a roof mounted solar hot water system, then you could be in trouble. It could be a leak from the storage tank itself or even a burst pipe from any connected plumbing.

Be sure to promptly turn off your water mains, and contact an emergency plumber.

All of my Hot Water is Lukewarm, Why?

For a gas, electric, solar or heat pump hot water system, lukewarm water is never welcomed. You could even say it receives a lukewarm reception! Sorry, dad joke.

A faulty or incorrectly set thermostat is often the cause of lukewarm water. Hot water delivery is required to be set at 50°C, and inside a storage tank can be heated to 60°C. Yet if a thermostat is not at this temperature, you’ll see a noticeable difference. 

The heating element may also be malfunctioning, requiring urgent attention.

Other reasons include a faulty diaphragm or tempering valve. A diaphragm is a rubber compound that deteriorates over time and eventually requires replacement. It’s found in continuous flow units, rather than storage tanks.

Blockages within a tempering valve can also impact the mixing capabilities, and the water coming out of your taps.

Why Is My Water Pressure So Low?

Low hot water pressure is a frustrating thing. There’s nothing appealing about a bad shower where water trickles out in a sad dribble. 

If you are dealing with poor water pressure, the most common causes are:

Clogged Pipes

Debris or sediment within the plumbing or hot water system itself will impact the amount of water flowing throughout your pipes. Debris can build up, blocking the flow and limiting your taps to a disappointing delivery.

Dirty or Poor Quality Tapware

An old showerhead caked in limescale, or clogged with debris, will leave you with a below-par shower experience. You can either clean the showerhead with vinegar for a fresh shower service or upgrade to brand new tapware.

It’s important to acknowledge that new low flow showerheads also don’t equate to low pressure. They’re designed to provide a strong pressure with fewer litres of water per minute.

Water Leaks or Burst Pipes

If a pipe has sprung a leak then your water pressure throughout the home will take a hit. The loss of momentum weakens the force behind the water flow. Whether it’s a small leak or a nasty burst pipe, low pressure could easily be a sign of bigger plumbing issues. Contact a licensed plumber for leak detection and emergency plumbing repairs.

Should I be Worried if my Hot Water is Brown?

Discoloured water is always a concern, although you don’t have to panic. 

Sediment build up inside a hot water tank is common, and it often settles to the bottom. However, the first signs of discolouration are a perfect opportunity for you to book a service. Alongside brownish, more yellowed water, also keep a nose out for any smells or strange odours.

Bacteria in the Water

One of the most common bacteria to blame for discoloured hot water are iron-reducing bacteria. They oxidise iron particles, but the byproduct of the process is something that causes a brownish discolouration.

There are certain chemicals, like chlorine, which can kill them but it is not a solution to attempt on your own.

Tank Corrosion and Rusty Pipes

Although water heaters are designed to be incredibly durable with stainless steel or vitreous enamel tanks, they will corrode and rust over time. The same can be said for any plumbing in the home. 

A sacrificial anode can be found in stainless steel tanks, which is there to purposely attract rust. It can be replaced easily during a service. Still, for whatever reason, rust can build up and particles will break off. Typically they settle at the bottom of a tank but can be caught up in the top layer of hot water which flows through your pipes.

This leads to a brownish water colour. Often the best solution is to drain the storage tank, something that a professional plumber should always do.

Sediment and Dirt

There’s always a chance that the sediment and dirt in your water are from an external source. Incoming mains supplied water may not be filtered properly, for whatever reason, and can occasionally become discoloured on a large scale.

Major storms can also contaminate local water supplies if a large amount of stormwater flows throughout plumbing systems. 

How Can I Make Sure my Hot Water is a Safe Temperature?

The dangers of extremely hot water are always a concern, especially to parents. It takes just half a second for a child to receive third-degree burns from hot water at 70°C. Thankfully, there are precautions in place.

Although hot water systems are required to be 60°C or higher to prevent the growth of legionella bacteria, tempering valves allow a maximum of 50°C to flow through your pipes.

Even though this is still quite hot on its own, it would take roughly 5 minutes of constant exposure for third-degree burns, instead of seconds.

Many advanced hot water systems also allow you to directly set the temperature for your shower, helping provide a balanced and comfortable experience.

How Do I Make My Hot Water System Last Longer?

Annual servicing and regular maintenance is the best way to make your water heater last longer. A well looked after unit should easily power past the average 10-year lifespan with gas instantaneous units often lasting closer to 20 years.

Routine maintenance will look after key parts such as the sacrificial anode, thermostat, heating element, etc. And if each part is in pristine condition for longer, your hot water system remains more efficient.

You can also keep the surrounding area clean from debris, plant matter and nesting animals.

Always feel comfortable in contacting a local, friendly Jim’s Plumbing expert for emergency repairs or servicing. We’ll keep your hot water in premium condition!

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