Low
93 on Viessmann Vitodens 343-F WS4A

The boiler has detected a faulty temperature reading from its solar heating system, which is usually a sensor problem that does not stop your main heating or hot water from working.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Control mode. Solar: Sensor S3 at the Vitosolic shorted out.

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 343 F Ws4a 5592883 installation & service 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.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

A cover plan would handle faults like 93: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

All 59 fault codes on the Vitodens 343-F WS4A

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

Related guides you might find useful