Hot water really hot and bathroom radiator randomly coming on (with pics)

[itsmehere1]

Since past 2 weeks, our bathroom radiator comes on automatically even when heating is off. Also the hot water coming from any tap/ shower is really scalding hot. Husband thinks our thermostat is faulty. I have attached few pics. Can someone help? Should we call a plumber or heating engineer? What is it likely to be? Thank you.

How long have you lived there? With a standard boiler the bathroom rads will come on when your water is being heated. It's separate from your heating, and from your thermostat.

So. Is your hot water set to come on all day? So it is heating up whenever you use some. Your system timer should have separate settings for heat and hot water. Google your timer and make sure you have set heating and hot water to come on independently.

There should also be a heat setting on your boiler, and additionally a themostat on your tank. Make sure your immersion switch is off at the tank too!

If you don't have the manuals, there are lots and lots of YouTube folk, who will walk you through. Just Google your boiler type and additionally your heat/hot water timer.

Good luck. If you are still bamboozled get a plumber in!

If it’s a combi boiler my money is on a faulty diverter valve. Contrary to the above post, your radiators shouldn’t come on when hot water is run. The valve itself isn’t too expensive and maybe a couple of hours of labour tops so perhaps £200 or thereabouts all in depending on which area of the country you’re in.

Thank you for your reply! We have lived here 5 years. We never had towel rail radiator coming on before. Will look up the timers and manuals.

What @NonmagicMike says, we had radiarors coming on in the summer when they shouldn't, we soon realised it was when we ran hot water. Pumper fixed it no problem.

It’s not a combo boiler, have attached pics if helpful thanks

So that's your heating and hot water controls (not your thermostat). Looks like you've pressed the boost button on both as the lights are on.

What's the 1st picture? Is it the hot water cylinder?

Is the last picture your diverter valve? We had to get ours replaced as the heating was coming on really hot even when our thermostat was turned down.

Can you see a 2/3 port valve?

We don't have a combi boiler, but have had problems with the diverter valves a number of times. Starts with one radiator coming on and the only way to cool the hot water down is to put the heating on full all over the house as we have two heating zones and two thermostats