Condensate discharge run externally without protection
What it looks like
Boiler lockout in the first hard frost of the winter, usually across a number of plots on the same site at once.
Why it happens
Condensate pipe taken outside in small-bore plastic and run a long distance to a gully, without insulation or the required fall.
What it costs if it is missed
Nuisance boiler failures after handover, customer care visits across the site, and avoidable reputational damage in the first heating season.
How to inspect for it
Trace the condensate run at second fix: internal termination preferred, external runs kept short, in a larger bore, insulated and falling continuously to the discharge point.
How to prevent it
Design the condensate route at first fix with the heating layout instead of leaving it to the commissioning engineer.
Basis in regulation
Last updated 23 August 2026. This is our editorial summary of publicly available regulation and site practice, not building control approval or a warranty determination.