Radiators Coming On With Your Hot Water? This Is The Cause


It’s funny how the weather can affect the kinds of calls we get.

This week, I’ve had two call outs from people whose heating is coming on when they don’t want it to, which isn’t ideal in the warm weather.

For both customers, their radiators were heating up when they turned on their hot water. So even when their heating was turned off and their thermostat was turned down, their heating was still belting out. Not what you need when it’s 26 degrees outside!

The cause of this problem is usually a part called a mid position (or 3 port) valve.

When it works properly, it diverts the flow of water from your boiler to either your radiators or to your hot water cylinder to heat up your hot water.

The reason your radiators heat up – even with the heating off – is because the valve doesn’t close off the heating side of it fully. This means water can still pump around the radiators when the heating should be off.

There’s not much you can do when a mid position / 3 port valve does this, except to change it.

We’d need to drain your heating system to do this, so the job usually takes a couple of hours, but will vary depending on how big your system is and where your 3 port valve is.

A new valve almost always solves this problem, except in on rare occasions when it’s something else.

What is that something else?

Well, like it said, it’s rare, so this probably isn’t causing your problem, but I’ll explain it anyway.

It’s called “reverse circulation”.

This means the water that’s meant to go back to your boiler (called the “heating return”) to be reheated goes somewhere else. Usually around your radiators.

So rather than the heating return going back to your boiler, some of it goes the wrong way around your radiators.

Most of the time, this is a fairly easy fix with a well placed non-return valve.

So even if your system suffers from this rare problem, it shouldn’t be too hard to fix.

Post time: Sep-18-2017
  • * CAPTCHA: Please select the Cup

WhatsApp Online Chat !