Baxi combi boilers have the great ability to provide hot water and heating in one well packaged unit. But as with any modern powerful appliance with many functioning parts, sometimes things can go wrong. Here, we look at why Baxi boilers sometimes have hot water issues.
If you rely on your Baxi boiler to provide hot water and it’s not firing up as expected, it can be quite frustrating, especially during the chilly months. Several factors can contribute to this issue, and it’s essential to address them promptly to restore your hot water supply.
Baxi boiler no hot water causes
If your Baxi boiler has no hot water, the most common cause is boiler pressure being too low or high. Other causes include seasonal temperature fluctuations, water flow rates in the system, and faults with electrical boiler parts. Some issues you will be able to fix yourself while others will need a gas engineer to resolve.
Other causes are seasonal temperatures, water flow rates with no water flowing in the system at all, and faults with electrical boiler parts. Some issues you will be able to fix yourself while others will need a gas engineer to resolve.
Baxi Boiler Keeps Losing Pressure? How To Re-pressurise
Most houses have a combination boiler that combines into one unit instantaneous hot water for the taps and heating for the radiators. Baxi combis are among the most popular.
Causes of no hot water from a boiler
We look at the main causes and also give you tips to fix these issues before you call an engineer.
Check the Power Supply
The first step is to ensure that your Baxi boiler is receiving an adequate power supply. Start by checking if the boiler is properly connected to the mains and that the power switch is turned on. If the boiler is connected to a fused spur, check if the fuse hasn’t blown. In case of a tripped circuit breaker, reset it and observe if the boiler starts functioning.
Check the Gas Supply
A common reason for a Baxi boiler not firing up is a disrupted gas supply. Ensure that the gas supply to the boiler is turned on and that the gas meter is functioning correctly. If you’re using a gas tank, check if it has enough gas to power the boiler. Additionally, examine the gas pipes for any leaks or blockages that could be hindering the flow of gas.
Inspect the Water Pressure
Inadequate water pressure can prevent the Baxi boiler from firing up for hot water. Check the pressure gauge on the boiler; it should ideally be between 1 and 1.5 bars when the system is cold. If the pressure is too low, you might need to repressurise the system following the manufacturer’s guidelines.
Thermostat set too low
If the water isn’t hot enough, it could be easily fixed by checking the hot water control on the boiler. Check the water temperature setting on the boiler itself, this could be set too low. If you are getting only lukewarm water, try turning the setting to maximum.
Reset the Boiler
In some cases, a simple boiler reset can resolve the issue. Locate the reset button on your Baxi boiler, usually found on the front control panel. Press and hold it for a few seconds, then release. The boiler will go through a reset cycle, and if there are no critical faults, it should start working again.
Wrong sized boiler for the property
The Baxi combi boiler may be too small for the size of the property or the number of people in the household who use water at the same time. The boiler could be too small for the demand for hot water it receives and it cannot heat the water up quick enough. You should look to upgrade to a higher kW boiler if this is the case.
Baxi Boiler No Hot Water? Do These Simple Checks
No water coming out of hot tap
If your central heating is working fine but having issues with hot water, the likely cause could be one of two things: a faulty diverter valve – run a hot tap for 10 minutes and check if the central heating system is warm but not the hot tap, this is the reason. Secondly, the plate heat exchanger is blocked up with sludge or debris, especially without a boiler filter.
If no hot water comes out of one tap or the shower, the reason could be a clogged up pipe to that tap – from limescale or other minerals; or there may be an airlock in that branch of pipework. This can happen when work has been done on any part of the system.
An annual homecare plan from HomeTree can help give you peace of mind with this. Click here for more info.
Seek Professional Assistance
If you’ve followed all the steps above and your Baxi boiler still refuses to fire up for hot water, it’s time to seek the help of a qualified heating engineer. They have the expertise and diagnostic tools to identify complex issues and offer the appropriate solutions. They will go through any of the following diagnostics:
Clear Any Blockages
Blockages in the boiler’s pipes or heating system can impede the flow of water and cause the boiler not to fire up. Inspect the pipes and radiators for any obstructions, such as sludge or debris. If you find any, flush the system to remove the blockages and restore proper water circulation.
Blocked heat exchanger
For a Baxi combi boiler, the plate heat exchanger which heats the water for the taps can become blocked with limescale and will need cleaning or be replaced altogether. If in that heat exchanger, the heating side becomes blocked, it will likely be due to sludge build up. This can affect the hot water part too.
Faulty diverter valve
The diverter valve directs where the hot water goes – either to the taps or the radiators. In a Baxi combi boiler, a faulty diverter valve can mean hot water only works when the heating is on.
This is obviously not good in summer when you only need hot water and not heating. You normally notice this fault in the summer.
Alternatively, it could be passing heat down the central heating flow pipe, causing lukewarm water at the taps.
Thermistor out of calibration
Another cause of no hot water is one of the thermistors being out of calibration. This will send the wrong information to the PCB (printed circuit board) so the water temperature never rises to become hot.
Faucets and taps causing hot water to become cool
Mixer taps and shower mixers especially those that have a single cartridge have in them rubber O rings that can wear out, so the cold water can cross over into the hot side. The fix for this is to replace the cartridge with a new one which should solve the problem.
Seasonal temperatures
Sometimes there is nothing wrong with the boiler but it’s the season that affects the water temperature. The combi boiler is designed to increase the water temperature by 40⁰C from the cold mains.
In the winter months, the groundwater temperature is colder so the boiler raises it by 40⁰ as it should, but it feels colder than in summer simply because the summer water temperature in the mains can be as high as 19⁰ whereas in winter it can be as low as 2⁰.
If you want to use the services of a plumber, check out the full house service offered by HomeTree on our recommended page.
Check water flow through the boiler
The flow of water through the boiler may be going too fast. Combi boilers are designed to heat water optimally at certain flow rates stated as litres per minute l/m. Different-sized boilers can handle differing flow rates. Baxi combis range from 12 to 20 litres depending on the boiler size.
Maybe the water flow rate is too fast for the Baxi boiler you have installed. You should call an engineer who will check the water flow rate and if it’s going too fast, may be able to adjust it down when it goes into the boiler so the boiler has more time to heat the water up.
If the boiler shows it’s heating the water to a high enough temperature, but you still feel the temperature isn’t hot enough, you can try to adjust the flow of water down to a particular hot tap, say, in the kitchen sink. You don’t need to adjust anything on the boiler.
With the slower flow of water to a particular hot tap, it should raise the temperature of the water. You can usually find a valve on the inlet pipe to the hot tap and turn this to slow the flow. This will mean the heat exchanger has more time to heat the water and so give you hotter water.
It is usually only the kitchen sink hot tap where you want hotter water, the bath and basin temperature can become too hot to bathe and wash in.
Another way to get hot water quickly is after turning the tap on to let the boiler fire up and then slow the tap rate down so it’s running slowly, i.e. partially close the tap so it’s not at full flow, and this will give the boiler more time to heat the water.
You use less water this way and get hot water quicker too.
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