What is fluing?
It is the exhaust of the gas, which mostly what comes out is like steam, like boiled water. Now if you have a very long flue going up, that condensate cannot go up to the top so it therefore runs down the pipe through the flue fan into a container which is the sump from that sump it runs through a tube into the pump container where then very slowly builds up until it reaches a certain level where the pump will get activated. and pump that water on top into that tray from the humidification.
If you are on an external wall, you can use what we have a coaxial flue, meaning there is a 14 mil exhaust pipe, exhausting out, inside is 65 mil pipe and the space between the 40 and the 65 mil pipe is your air intake for combustion. That’s what you need. If you don’t have that air, well the heater won’t work. And with that you have slightly less humidification because the distance is short. So some of that steam runs through the outside but when you first light the heater, for about half an hour, you will see the steam outside after that you will see nothing.
Do gas heaters need a chimney?
No, but f you have a chimney you can run a 40 mil PVC pipe in that chimney, but it must always be terminated outside, so that you can put a plate on top of the chimney. Thii ensures that there’s no water coming in. And the 40 mil pipe goes through a plate with a cowl to the outside.
You cannot exhaust into the chimney, because you would get steam in the chimney and that does not work. It must always be vented to the outside atmosphere.