BoilerFaultCodes.com
S.52 Low Information

Your boiler is in a waiting period because the air or flue system has detected a minor issue while trying to start up.

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.

Technical description: Check status code (Page 52) / Check diagnostic code (Page 53)

What causes this fault?

This fault occurs when the boiler's internal safety sensors detect a delay or minor obstruction in the air flow needed for combustion. It is typically caused by a tiring fan that is struggling to reach the correct speed or an air pressure switch that is failing to click over. The boiler pauses its startup sequence to ensure it can exhaust waste gases safely before fully firing up.

This issue can be more frequent during windy weather, as high gusts can occasionally interfere with the pressure signals at the external flue terminal.

Typical repair cost £90-250 (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 S.52 — no call-out fees, no surprises.

Top rated
OpenFix
Boiler & heating care plans
Get a quote →
Hometree
from £12.95/month
Get a quote →
HomeServe
from £8.00/month
Get a quote →

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

Vaillant Thermocompact 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.

UK's #1 online installer
Boxt
Fixed-price online quotes. Next-day installation.
Get a free quote →
Heatable
Instant online boiler quotes from £1,499.
Get a free quote →
iHeat
Fast installation. Price match guarantee.
Get a free quote →

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

Related fault codes