Baxi Ecogen 24/1.0 Installation & Servicing Instructions Manual page 18

ii) External termination via internal discharge branch e.g sink waste ­ downstream*
page 20
11. When discharging condensate into a soil stack or waste pipe the effects of existing plumbing must be considered.
If soil pipes or waste pipes are subjected to internal pressure fluctuations when WC's are flushed or sinks emptied then back­pressure may force water out of the boiler
trap and cause appliance lockout.
iii) Termination to a drain or gully
iv) Termination to a purpose made soakaway Further specific requirements for soakaway design are referred to in BS 6798.