Arrived on site, and found drain line not draining properly. Blew out drain line with nitrogen and line would drain initially. However, I would receive back pressure shorty there after stopping the line from draining. Adjusted pitch of drain line to ensure that was not the issue, and had no different results. Upon tracing the drain line, I found water leaking out of the cast iron vent pipe that the drain line was tied into. Advised homeowner that unit may not work properly until this issue is addressed and that a plumber would need to address this issue. I advised the homeowner that we could run another drain line draining outside into an irrigation box, however I recommended addressing the larger issue with the vent pipe. Unit running upon departure, and drain line intermittently draining.
