Central Heating Faults – My Radiators are Hot upstairs but Cold Downstairs

Central Heating Pump

The central heating pump pushes water from your boiler or hot water tank around your central heating system so that the water in your pipe work and radiators is constantly moving.

It does this so that the whole system works at an even temperature. Without the pump the hot water would not get very far from the heat source, so it might only heat one small area or even only one radiator. Because heat rises this warm area is likely to be the radiators upstairs in a house, or if you live in a flat it would most likely to be the radiator/s nearest the boiler or hot water tank. You can read more about diagnosing radiator problems in our projects section.

If your radiators are hot upstairs and cold downstairs it is most likely that your pump is not working correctly.

DIY Tip

Try turning up the pressure on your central heating pump. This is usually easily adjusted using a small lever on the pump (see and example pictured below). Refer to the manufacturers instructions to find out where your pump is adjusted. For other heating faults see our project on Central Heating Problems.

That Doesn’t Fix it

If this doesn’t solve the problem then you may have to replace the heating pump. Please be careful doing this as the heating pump is powered by electricity. You must isolate it from the mains before you start work, and if you need to employ a tradesman make sure they are a qualified and insured heating engineer.

Keeping Your Pump Working

If you do any maintenance work on your central heating system, especially if you are draining-down the system, it is always a good idea to introduce a scale inhibitor in the system. This helps prevent the build-up of limescale which can cause damage to the pipe joints, clog up the central heating pump and, together with some rust, cause a layer of ‘silt’ to build up inside radiators. All of these make the central heating less efficient, which may mean your boiler and pump are working harder than they need to. See our projects on dealing with limescale.