When your boiler is turning on and off (also called “short-cycling”), it’s generally because a safety feature has kicked in. For example, some are simple, but others require a Gas Safe engineer. We will explain seven of them, how to inspect them, and a safe way to do so.
The starting pressure of almost all combi boilers needs to be about 1-1.5 bar when they are cold. The boiler could then turn off to protect itself if it falls too low. Refer to the pressure gauge, and if your manual permits it, use the filling loop.
2) Pressure too high
Similarly, the boiler may also turn off or leak water via its pressure relief valve due to high pressure (typically at 2.5-3 bar). This typically occurs after adding too much pressure or if there is a problem with the expansion vessel.
3) Freezing of the condensate pipe (frequent problem in UK cold snaps)
The boiler stops working and displays an error code, because in winter the condensate pipe is frozen. Signals of this could comprise gurgling, a fault message or the boiler cycling on and off frequently. But simply thawing the pipe can be a dangerous procedure unless you know what to do, in which case it would probably be best to consult with an engineer. For Boiler Repair Cheltenham, contact https://www.hprservicesltd.com/cheltenham-boilers/boiler-repair-cheltenham/
4) Thermostat or programmer issues
A boiler may seem to switch off at random because the thermostat is faulty or in a bad position. Test batteries (if any), verify the time and date, and reset in case of doubt.
5) Pump issues or circulation is not good
An imbalance in the flow of water would cause the boiler to overheat and shut down. Symptoms: You can see the pipes near where they connect to the boiler starting to stiffen and heat up while radiators continue or turn off. This might mean a problem with pumping, valves being stuck, or the system not being very well balanced.
6) Sludge or scaling produces fouling to drive overheating
When the heat exchanger is clogged, sludge has entered, and there’s a lot of limescale built up; so it continues to overheat, then overheats again quickly afterwards. Loud banging/whining noises during operation.
7) Flame or ignition faults
Safety cutouts can occur if the flame is not stable in a boiler. This might also be attributed to the ignition parts, gas supply issues or sensors.
Stop troubleshooting if you smell gas, see a yellow/orange flame or feel unwell. Always shutting down will need attention before it turns into a pricier fix.
