Baxi Boiler No Hot Water

Which Baxi problem do you have?

Most Baxi combis, including the 200, 400, 600 and 800 ranges, show faults as a code on a small digital display. Before touching anything, look at three things, the same first checks as for any boiler that is not heating water: whether a code starting with E is showing, whether the radiators heat, and whether hot water comes at all or only lukewarm.

• No heating and no hot water, with a code: a whole-boiler fault. Go to the codes section below.
• Heating works, no hot water, no code: a hot water side part. See the tap test.
• Hot water works, no heating: controls, circulation or the diverter stuck on the hot water side.
• Hot water lukewarm or surging hot and cold: usually limescale in the plate heat exchanger.

Baxi codes that switch off your hot water

E118 or E119, depending on the model, means the heating circuit pressure has dropped too low for the boiler to run safely, and the boiler has shut down to protect itself. Topping up with the filling loop usually brings it back; the full steps are in Baxi E119 and Baxi boiler pressure.

E133 means the boiler has tried to light and failed. Check your gas is on at the meter, other gas appliances work, and a prepayment meter has credit. In cold weather, also check the white condensate pipe outside has not frozen. One reset is fine; if E133 returns, it needs an engineer.

E50 points to a fault with the hot water temperature sensor. It is not something you can fix, but it confirms the boiler has spotted a hot water problem on its own. Other codes, such as E110 for overheating or E125 for a circulation fault, usually stop the heating too. If your display shows only E1 followed by more digits, read Baxi E1 to decode it.

To reset a Baxi with a selector knob, turn it to R, hold it for around five seconds and release it. Models with buttons have a reset button instead; the user guide shows which. Reset once only. A code that keeps returning is the boiler telling you a part is failing.

If you smell gas, do not reset or relight anything. Open the windows, turn off the gas at the meter if it is safe to reach, leave light switches alone, then get outside and call the National Gas Emergency Service on 0800 111 999.

Heating works but the tap stays cold

With no code on the display, run a quick test. Turn the heating down at the thermostat, then open the kitchen hot tap fully and watch the boiler. On many Baxi combis a tap symbol appears and the fan starts within a few seconds.

If nothing happens, the boiler has not seen the tap open. The flow sensor on the cold inlet has stuck, or there is not enough mains flow reaching it. Run the cold tap to check the supply; if it is strong, the sensor is the likely culprit.

If the boiler fires and the radiators get warm while you run the tap, the diverter valve is stuck in the heating position. On many Baxi combis the diverter is a motor head fitted on a brass or plastic valve body, and either the motor or the valve inside can fail.

If the boiler fires, the radiators stay cold and the tap only goes lukewarm, heat is not getting through the plate heat exchanger. Hard water, which is what most of London gets, scales these up over time. The general version of this test for every make is in heating on but no hot water.

Before blaming a part, check the hot water temperature control on the boiler. On Baxi combis it is either a second knob or a button with a tap symbol, and it is easy to knock to its minimum while cleaning or after a service. Set it to about the middle of the range, then repeat the tap test. If the water is now hot, nothing was broken.

Baxi hot water but no heating

This is the reverse fault and it is common on Baxi combis. First check the heating is actually being asked for: the heating selector is not turned to off, the programmer or smart thermostat is in a heating period, and the room thermostat is set above the room temperature.

If the controls are calling and the boiler fires but the radiators stay cold, the diverter valve may be stuck in the hot water position, or the pump is not moving water round the radiators. An E125 code points to circulation. If only some radiators are cold, the fault is in the heating system rather than the boiler; see boiler not heating radiators and hot water but no central heating.

What gets replaced on a Baxi, and typical costs

An engineer will put the boiler into its diagnostic mode, confirm whether the flow sensor is responding and which way the diverter is driving, and measure the water temperature at the tap. Ask which part has failed and why before agreeing a price; on a hot water fault the answer should be one specific part, not a list.

Typical market ranges with fitting are roughly £120 to £250 for a flow sensor, £180 to £400 for a diverter valve or motor, £80 to £200 for a hot water temperature sensor, and £300 to £600 for a plate heat exchanger. Descaling the plate heat exchanger can be an option when the plates are not damaged.

Our Baxi boiler repair visit starts with the £60 call-out at any hour, and the repair price is agreed with you on site before any work starts. Gas work is carried out by Gas Safe registered engineers. For how a no hot water visit runs, see no hot water repair.