Bosch Thermotechnology · Error codes
Bosch/Buderus SSB85-160 62 — Blocked Drain Error
62
Blocked Drain Error. Block drain switch is active The table classifies it as blocking.
Applies to
This venting or air-supply fault code is displayed by the SSB control on SSB85, SSB120 and SSB160 models, as documented in SSB85/120/160 Service Manual, doc 6720866940 (11.2017), sections 9.9–9.10 (6720866940). Codes can differ between controller generations, so always check the manual that matches your unit.
- Bosch Thermotechnology Buderus SSB (85-512, discontinued)
- Buderus SSB85
- Buderus SSB120
- Buderus SSB160
- Buderus SSB255
- Buderus SSB399
- Buderus SSB512
Controller: SSB control. Source manual: 6720866940.
Why a code is not a diagnosis
A venting or air-supply code points at the combustion-air path: a blocked terminal, a restricted flue, a failed fan, or a condensate restriction. It does not say which, and running an appliance with a blocked flue is unsafe.
Safe things to observe
- If a carbon-monoxide alarm sounds anywhere in the building, leave immediately and call 911 from outside.
- From a safe distance, check that the vent terminal and combustion-air inlet are not blocked.
- Do not run the appliance while a blockage is suspected.
Do not
- Do not put anything into the vent or air-intake openings.
- Do not remove or modify vent pipe.
How professional service helps
- A technician inspects the full vent and combustion-air path, clears blockages and checks the fan.
- Combustion and safety devices are verified with an analyser and the manufacturer's procedure after any repair.
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Frequently asked questions
Can I clear this code myself?
Clearing a code without fixing its cause usually just brings it back. Note the code, check the safe items on this page, then call a licensed technician. If your appliance manual describes a user reset for this exact code and it stays away, no call may be needed.
Boiler locked out? Call with the alert text ready.
The brand, model and this alert are passed along when you request service online, so the technician arrives prepared.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- SSB85/120/160 Service Manual, doc 6720866940 (11.2017), sections 9.9–9.10 · 6720866940 · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.