We do a lot of heating systems for second homes or lake cabins in remote areas. These houses have septic systems and minimum use all winter so having high efficiency condensing appliances introducing a trickle of flue gas condensate down the drain all winter can be a huge problem with dormant septic tanks and exterior main drain lines.
Typically we would run the gas boiler condensate drain directly to the floor drain and call it a day. In situations like this though that will almost always cause freezing at the septic tank inlet or in the main line from the house. This is due to the lack of use which isn’t introducing more bacteria, which would create heat.
A few years ago I started installing the Liberty 404 sump station to combat this issue. This sump would typically be used to add a sink where immediate plumbing access isn’t available. We use it because it allows the system to run as normal but instead of a trickle down the drain all day, the sump fills with a couple gallons and discharges all at once so there’s no possibility of freezing in the tank or line. Simply using a condensate pump is not enough to stop the freezing in this situation, the larger volume from the sump is needed.
I also pipe an overflow to the floor drain in case the pump fails when no one is around. Hope this helps and thank you for taking the time to read. If you’ve got questions or comments please add them below!