Air Pressure Switches (Testing)
Testing the boilers Air Pressure Switch, is always an indicator that other problems may exist. This article helps to diagnose the Air Pressure Switch issues on a boiler.
Air Pressure Switches (General)
Air pressure switches
(operating @ approx. 0.5 – 4 m/bar pressures)
See also: How to test your Air Pressure Switch with a multimeter
Reasons an air pressure switch will fail to start:
Loose electrical connections
Kinked or split rubber h...
Thermostats
Boiler Fault Finding - Thermostats - See also:
Cylinder Thermostats
Room Thermostats
Thermostats Overheat Cut out
Thermostats Liquid Expansion
Electrical Safety Checks - Resistance to Earth
Top Tips for the Heating Engineer...
Thermistors
What is a thermistor used for in a combi boiler
Boiler Fans
Reasons a fan will fail to start
No 240V supplying (L) & (N) terminals Burnt out motor windings Worn out bearings Air rotor jammed (on fan casing) impeller heavy with foreign matter accumulation Faulty fan speed control resistor (if fitted) ...
Circulating Pumps
A failure of the circulating pump can cause a number of problems, such as reduced heating and hot water performance, and can result in the boiler shutting down.