BoilerFaultCodes 30-80 (L, M, M, L, M, M) Medium
Your boiler has lost the ability to detect the temperature of the water used for your taps and shower, so it has stopped providing hot water to ensure safety.
Book a service
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Thermistor sanitary open
Typical repair cost £120-220 (including labour)
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 30-80 (L, M, M, L, M, M) — no call-out fees, no surprises.
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Chaffoteaux Calydra 100 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.
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