Heating Not Working After Summer? 7 Checks Before Calling an Engineer

You turn the heating on for the first chilly morning, but the radiators stay cold. Before booking a repair, there are a few simple checks you can make without opening the boiler or touching any gas components.

Here is a practical checklist for homeowners in Hastings, St Leonards-on-Sea and the surrounding area.

1. Check the room thermostat

Turn the thermostat above the current room temperature and make sure it is set to heating, rather than an off or summer mode. If it is wireless, check its screen and batteries. A thermostat that is already satisfied will not ask the boiler to heat the radiators.

2. Check the timer or programmer

After months without central heating, the programmer may still be set to off, or its schedule may no longer suit you. Try its normal heating-on setting and check the time and date. If you have a smart thermostat, check its app and internet connection too.

3. Look at the boiler display

Is the display on? Does it show a fault code, a low-pressure warning or a heating symbol? Make a note of the exact code and the boiler model before you call. The manufacturer’s instructions may explain a user-level reset, but avoid repeated resets if the fault returns.

4. Read the pressure gauge if you have a sealed system

Many sealed heating systems need roughly 1 to 1.5 bar when cold, but follow the pressure range in your boiler manual. If the reading is low, the manual may explain how to top it up. If you are unsure, leave it to an engineer. A pressure reading that repeatedly drops can point to a leak or another fault; repeatedly topping up is not a repair. Open-vented systems may not have a pressure gauge.

5. Check radiator valves

If only one radiator is cold, check that its thermostatic radiator valve (TRV) is not turned to the frost or off setting. If the rest of the system heats normally but that radiator stays cold, tell the engineer which room is affected. Do not force a stiff valve.

6. Compare heating and hot water

Do you have hot water but no central heating, or neither? On a combi boiler, that difference helps narrow down the fault. On a system with a hot-water cylinder, the controls and motorised valves may also be involved. Note what works and what does not; diagnosis still requires proper testing.

7. Look for visible leaks or signs of trouble

Check around accessible radiators and pipework for water. If water is leaking near electrics, keep clear and arrange urgent help. If you smell gas, do not operate electrical switches or use a flame: leave the property and call the National Gas Emergency Service on 0800 111 999.

When should you call a heating engineer?

Call if the boiler displays a persistent fault, pressure keeps falling, radiators remain cold after the basic checks, or you have no heat or hot water. Never remove a gas boiler’s case to investigate. A Gas Safe registered engineer can test the boiler and heating controls and explain the repair.

ZSU Ltd provides central heating repairs and boiler fault diagnosis in Hastings and surrounding areas. Call 07963 590 223 and tell us the boiler make, fault code and which checks you have already tried.

Further reading: Energy Saving Trust’s winter preparation advice.