Medium
E 33 on Ariston Euro Prisma 24

Your boiler has stopped because it thinks a safety switch connected to your underfloor heating has been triggered or disconnected.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Floor heating thermostat open circuit (if fitted) (ROOM THERMOSTATFLOOR)

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 25 fault codes on the Euro Prisma 24

Seeing a different code? Every code this model can display, in one place.

A 18A 37A 39A 40A 41E 05E 06E 07E 08E 09E 10E 11E 12E 13E 14E 15E 16E 18E 20E 29E 30E 37E 38E04

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