How to fix hot water not coming through to kitchen?

Question

Hi everyone, the hot water in the kitchen either does not come through (ie water comes through but it is cold) or comes through (ie heats up) only after I turn other hot water taps on (eg laundry). I don't have an issue with hot water flowing in the laundry or the bathroom. The kitchen is as close to the hot water heater as the laundry is, and closer to the heater than the bathroom. Does anyone have ideas as to what the problem may be? Cheers.

JacobZ · Accepted Answer

Hi @Papa_T,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

The fact that hot water only comes through the kitchen tap when another hot water tap is turned on suggests a flow restriction or pressure imbalance in the kitchen’s hot water line.

Start with the simplest checks first. Begin by removing and cleaning the tap’s aerator (the small mesh fitting at the end of the spout). Sediment or mineral build-up can restrict flow, especially in the hot line, reducing pressure enough that water stays cold until another tap increases system flow.

If you have a mixer tap, the next likely issue is a partially blocked or faulty cartridge inside the tap. Over time, debris or scale can clog the hot water side, preventing adequate flow. Replacing or cleaning this cartridge is a relatively simple job that could help to fix the issue. If you have a mixer tap and feel this could be the issue, let me know so I can assist with this.

A more complex but possible cause is cross-flow or a faulty tempering valve. In some situations, a worn mixer cartridge or tempering valve can allow cold water to push back into the hot line, upsetting the balance and preventing proper hot flow until another tap is opened. Diagnosing and repairing this requires a plumber, as it involves checking the plumbing configuration and possibly replacing valves.

Try cleaning the aerator first, then check out the mixer cartridge. If these issues don't solve the problem, then unfortunately, you are going to have to speak with a plumber for their assistance.

Let me know if you have further questions.

Jacob