BoilerFaultCodesYour boiler has detected that it is firing without enough water inside, which has caused the temperature sensors to overheat or report a fault.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: DRY FIRE THERMISTOR ERROR
What causes this fault?
This fault occurs when the boiler fires up but detects an immediate, rapid rise in heat because there isn't enough water circulating to carry that heat away. The most common reasons are a severely trapped pocket of air, a seized pump, or a major blockage in the pipework that is preventing water from reaching the heat exchanger.
This issue is more frequent in autumn when heating systems are switched back on after a long summer break, as pump components can seize up during periods of inactivity.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 93 H.....4.... — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Esprit HE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.