I have a mixer tap in my kitchen sink. It works 100% fine, except that when it is set to provide only a small amount of hot water, after about a minute it starts to run cold. This means that if I try to run medium temperature water at medium power, it runs cold. What could cause this?
there likely is a restriction in the gas or water inlet at your boiler. remove the inlets and clean out the debris and that will fix the problem.
I should probably have mentioned this before - there is no problem with any of the other taps in the house, only the kitchen tap, so I don't think it can be a problem at the boiler end. Do you think there is debris somewhere in the pipework for the tap?
,I should probably have mentioned this before - there is no problem with any of the other taps in the house, only the kitchen tap, so I don't think it can be a problem at the boiler end. Do you think there is debris somewhere in the pipework for the tap?
Likely debris. Have you ever had the shut off on the inlet turned off?
I must be honest I don't know what the shutoff on the inlet is. The kitchen sink was moved recently so the plumber could well have turned off the water supply when he did that.
if the plumber used the original plumbing and moved it that could be the issue. the pipes that feed the faucet have shut offs on them. they are likely gate valves. gate valves operate by turning the handle which turns the stem which lowers the gate. often the stem breaks and the gate will not fully open leaving the water extremely restricted. if when you turn the faucet all the way to hot, if the water comes out really slow then that is the problem. the shut off will have to be replaced. i recommend a ball valve.
I have been doing plumbing work for 20 years. Both servicing and new construction installation on high end homes.