If the heating fails, tenants and homeowners quickly panic. This usually happens when it is really cold outside. The fact that many problems can be dealt with quickly yourself or together with a heating engineer makes things easier.

Heating is often not possible when the settings are incorrect, the valves are stuck, or individual components are defective. We show you what you should pay attention to using simple tips.

Our plumber in North Shore Beaches has come up with the following tips that can help you.

hot water heating problems

Check the heating system 

Homeowners come home on a cold winter afternoon and find out that the heating does not work. Many major problems can be quickly ruled out.

If the boiler is malfunctioning, the heating has failed

If the boiler is faulty, for example, essential parts of the system may be defective. Since troubleshooting can become an unsolvable task without specialist knowledge, it is advisable to call an installer quickly or get a replacement boiler.

With the appropriate error code and a description of the fault, the operator can prepare well for the operation and quickly solve the problem. 

Fuel supply problems

If the heating has failed, this may also be due to the fuel supply. Because the heating does not work if the burner receives too little or no fuel. This can happen, for example, when the level in the oil tank is particularly low.

Because then suspended matter from the floor will block pipes and valves. For this reason, homeowners should refuel whenever the containers are only a quarter full.

The regulation has been adjusted

The heating does not work if the heating control is adjusted. The heating function is deactivated when the system is in summer mode. If, on the other hand, it remains lukewarm on particularly cold days, an unfavorable setting can be the cause.

This can be fixed by checking the heating curve because this specifies what power is currently required. We explain how this works on the heating curve. 

Heating does not work because the pump is on strike

The heating pump conveys warm water through the entire system. This supplies the heating surfaces with energy and the house with cozy warmth. If the pump doesn’t work, no water flows and the heating has failed.

It can be checked, for example, with a screwdriver. Held between the ear and the pump, it should feel vibrations and noise. If the old circulation pump is defective, homeowners can even save money with a new and subsidized high-efficiency pump.

The pressure in the system is too low

If no malfunction can be determined, have you checked the control and is the pump working as planned? The following is also possible: The heating does not work because the pressure in the system is too low.

Because that too can disrupt the heat transfer and cause cold radiators. The problem can be determined by looking at the manometer. This is either integrated with the boiler or attached in its vicinity.

If the display in the single-family home does not show at least 1 to 1.5 bar, homeowners have to add heating water. If the pressure drops again and again. This indicates, for example, a defective expansion vessel or a leak in the system. In this case, an installer will help if the heating has failed.

The boiler is running, but radiators stay cold?

The causes cannot always be found in the boiler room. It may also be that the heating does not work because the heating surfaces are disturbed in their function.

If the valves are stuck, the heating fails 

A thermostatic valve can jam, especially at the beginning of the heating season. This regulates the heating water flow and ensures that enough heat always reaches the heating surface.

When it comes to checking the function, homeowners and tenants should first remove the rotating head. Underneath you will find a pen that should actually sit freely.

That means: If it is pushed into the valve by hand, it should also slide out by itself. If it gets stuck, however, it closes the valve and the heating does not work. To restore function, homeowners should apply some grease or oil to the valve pin and gently move it in and out several times with pliers. 

Heating is not possible due to air in the system

The air in the system is often the cause of heating surfaces that remain cold. Especially at the beginning of the heating season, tenants and homeowners can vent the radiators.

This works by slowly opening the ventilation valves of the affected heating surfaces with a special key. If water flows out, there is no air left, and the valve can be closed again.

By the way: There are two points to consider for optimal results. For example, tenants and homeowners should turn on the valves on all radiators and, if possible, turn off the pump. 

Radiators get unevenly warm

The heating does not work properly if no hydraulic balancing has been carried out. Because this ensures an optimal distribution of heat in the house. Without an adjustment, radiators that are very close to the boiler are too hot, while others remain lukewarm.

In addition to a functioning heating system, the measure also reduces energy costs. Because it relieves the load on the heating pump, enables lower temperatures and thus also lower heat losses in the system. Read on and discover the source of the problem, you will have heat in your home again.

The heating system consists of the emitters (radiators or underfloor heating) and a heat generator, and it can be a boiler of any type (gas, diesel, pellet), also typically incorporates some temperature control system (thermostat or probe environment).

Why does the heating not turn on?

There will be a problem with the control element, its connection or the boiler; We will review the basic operation of the process.

When the thermostat detects that there is less temperature than we have set, it sends an electrical signal to the boiler. When he receives the order, it begins to heat the water of the heating circuit and drives it with the pump to the radiators.

All this continues until the boiler’s internal temperature cuts, or the thermostat does it once it reaches the desired degrees.

How to turn on the heating?

It is necessary to have the boiler in winter mode (hot water and heating) and raise the thermostat until it reaches a temperature higher than that of the environment. If it is digital, a flame or other form will appear and if it is analog or wheel.

After this, the radiators should start to heat up – if not, you have to see what causes the problem.

Why doesn’t it heat up?

After doing the above and not getting results, follow these steps to find out what is failing:

A – Check that the thermostat sends a signal.

Turn up the temperature selector until it pops up the query mode programming, the temperature at jumping, time etc.

If it is digital, check that a low battery icon does not appear (or make sure the LCD is not losing intensity). Change the batteries to the thermostat. 

B – Verify that an icon related to heating appears on the boiler.

Remember that the boiler must be set to winter mode.

No indication (radiator symbol, flashing LED…) appears in the boiler and does nothing. It may be due to thermostat failure or that some connection cable has been disconnected (both in the thermostat and in the boiler).

The boiler detects the thermostat signal, starts but does not heat the radiators.

This is a symptom of failure in the 3-way valve, which has been fixed in hot water and does not pass to the radiators.

Another possible cause is that the radiators are closed, or the heating keys of the boiler are closed. You must open them for water to circulate through the circuit. Learn more about how to troubleshoot electric water heater problems.


If the heating system does not heat up, it can be due to the thermostat (selected low temperature, the battery is missing or broken), its connection (cable lose) or the boiler (3-way valve failure).