Central Heating Systems And Problems

Heating by water circulating through radiators may use gas, oil or solid fuel for the boiler. From the boiler onwards the circuits are basically the same.

Radiators are usually bracketed to a wall. If one becomes loose, the retaining screw may have a head for a spanner, but if it is slotted a screwdriver with a right-angled end may be needed. There are steadying brackets to hold the radiator in position, and these can loosen, but their screws may be tightened with a straight screwdriver.

The usual pipe connections are compression fittings. If one leaks, tighten it with an adjustable spanner. If leaking persists, call a plumber.

If a radiator feels hot at the bottom and much cooler at the top, there is air in it. This is more likely with radiators on the highest floor, as air rises in the system. It is advisable to check for air periodically, particularly after the system is put back into use for the winter. In most radiators there is a recessed square-ended projection at one end of the top. This takes a special key (obtainable from a builders’ supplier). Use a cloth over the end and hold a jar or other containerunder the vent. Unscrew the vent until the air is heard hissing out. Leave this open until the air ceases and water comes out, then tighten the vent again. To make sure all the air has gone, let the system operate and try the vent again later.

There may be sludge, so let it drain until the oil appears clear. Make sure the filler has a cover so that dirt cannot enter. If there is a vent pipe, wire mesh over its end will keep out dirt. If the tank becomes rusty, wire brush the affected parts, rub with abrasive, coat with a rust inhibitor fluid, then repaint the whole tank. Bitumastic paint is a good protection.

Where the supply pipe leaves the tank there should be a filter beside a stop cock. Clean the filter once a year or as necessary.


There is a drain cock under the storage tank. Open this briefly once a year and catch what comes out in a bucket.

And remove the filter element. Wash out the bowl and the element with petrol. Allow to dry, then re-assemble.

This filter should stop nearly all the dirt passing into the oil. If that element is fairly clean there is no need to do anything else, but there is another filter on the base of the boiler casing and it is reached by removing the front panel. If the boiler is functioning satisfactorily and the tank filter has been cleaned, leave this other filter for attention at the six-monthly servicing. If you suspect it is blocked, turn off the stop cock and remove any screws holding the lid of the filter. See********************* that the float inside moves freely. The filter unscrews from the side. Place a shallow container under it before loosening. Remove the filter and take it outside to wash in petrol. Dry

and replace it together with the lid.

SOLID FUEL SYSTEMS Always use the fuel specified and in the correct size. Keep the hopper filled. In modern boilers the fire-bed is automatically refilled from


the hopper, which should be kept full. Ash is easily removed by the ejection system, a simple, dust-free method. The tray needs emptying less frequently than in the old-fashioned boilers.

A solid-fuel boiler should be cleaned every six months. Remove the casing panels and the top. Put a clean cloth over the burner and use a wire brush to remove soot and other products of combustion from the furnace wall. Lift out as much as possible and finish with a vacuum cleaner hose.

Fire bars can be damaged and may need to be replaced. If your fireclay becomes damaged, patch it with fireclay cement which is available from a builders’ merchant. Clean the flue-way in the boiler when the system is out of use. Open the elbow at its bottom and remove anything deposited there. Have the chimney cleaned annually.


A gas-fired boiler does not require attention by the owner comparable with the other two systems and maintenance should be left to the regular servicing by an expert.

In some older systems water circulates naturally, making use of the tendency for hot water to rise, but most modern systems have a circulating pump in the outlet pipe from the boiler. If water does not circulate when the pump is running, this may be due to air in the pump. If there is a vent in the top of the pump, it may need a key similar to that for radiators or a screwdriver may work it. Open the valve and close it when water flows. The vent may be in the flow pipe above the pump and can be blown fuse

The system is usually controlled by two thermostats: one at the boiler controlling the hot water system and another in a room controlling the heating system. A timing device at the boiler controls whether one or both systems are used and when they go on and off.

Experience will show which are the best settings, but there is no need to set the hot water thermostat higher than the water can be used. If cold water has to be run as well as hot at the sink, heat is being wasted. Water at 140°F (60°C) should be about right. For room temperature 70°F (21°C) is usual, but for economy a few degrees less may be acceptable. Halls and lesser-used rooms may be down to 60°F (15°C) and bedrooms even less. Where the system does not control the heat exactly as wanted in the various places, it is possible there is a flow adjustment on the pump, but this usually requires a special key and its adjustment is better left to an expert.

If the pump fails to run, it may have broken and have to be replaced, or the fault may be electrical. Obviously, the greatest economy comes with turning off radiators where they are not needed, but there is little to be gained by turning them off for short periods as fuel will have to be used later to restore heat and saving may be nil.


In a soft water area there is no problem with a hot water system, but if the water is hard it deposits scale or fur and this is a particular problem in pipes, where the deposit has the effect of reducing the bore. Advice should be obtained about any need to soften water, when a new central heating system is installed.

If there is any doubt about the effect of hard water, it might be advisable to try a portable descaler capsule suspended in the supply tank. Chemical descaling kits also exist and it is possible to have a descaling unit fitted in the supply pipe.