Condensate line with no drain (sub Arctic climate)

Chewbacca319

Good day everyone, I live in Yellowknife Northwest Territories Canada where frankly speaking our winters are harsh. While extremely dry we get a lot of snowpack and frigid temps (totally normal to have cold spells that go from -30°C down to -50°C core temp) so how we heat our homes and the cost to do so is pretty important.

My home is older (late 80s manufactured home) that has been updated over the years and up until recently was heated by a biasi cast iron oil boiler. My setup is a bit unique in the fact that I have a detached heated garage (heated slab) where the boiler resides which then feeds a glycol send/return line underground in an insulated conduit up into my trailer to a fan coil that then distributes heat via forced air (floor ducts).

The problem Im facing is with my new boiler. I decided to upgrade this year because the cost of heating oil has over doubled in my region.. ($2.70 CAD a liter) and with my fuel consumption (3500 liters last year) staying on oil was cost prohibitive.

Long story short I hired a local outfit to take out the biasi unit and replace it with a high efficiency condensing boiler (Navein NHB-150H). The install went pretty smoothly all in all but one big issue that I'm concerned about going into the winter season is the condensate line.

I have no drainage in my garage whatsoever so what the installers did was adapt the 3/8 inch condensate to 3 inch PVC, (transition is inside the heated garage) which is then vented outside running parallel to the exterior wall, wrapped in heat trace and insulated, just dumping onto the gravel outside (doesn't break any codes here, very lax with that kinda stuff). I trusted them because they install these things for a living but it just isn't sitting right with me.

I have since installed a condensate pump to minimize more freeze-up but after more research I began to panic when I found out just how much condensate these boilers actually produce (about 0.82 gallons per gallon of propane). I'm not overly worried about the exhaust freezing as It is an extremely short run outside, with heat trace and the condensate pump, but what I am concerned is about the sheer amount of ice this line is going to shoot out over the winter.

What I came to find out after a good day of researching frantically at any way to realistically solve this issue (that doesn't cost a fortune) was that these condensing boilers produce significantly less condensate if the operating temperature on the return line is above 130-140°F because at that point the heat exchanger won't actually condense the vapor back into a liquid state.

I noticed that the installer set the target temp to 170°F and when running it often climbs to 180-185 and down to around 160 in standby. I know at those temps I'm loosing the efficiency gains you get from condensing the vapor back into liquid but it would appear that the amount of condensate it produces is significantly less.

I'm not sure if the installer did that intentionally since I didn't have a good place to dump the condensate indoors or it's just precaution for the potential heat loss the glycol lines run to the house but am I correct in believing that as it gets colder the boiler will run more frequently at a higher operating temp, where condensing doesn't occur majority of the time resulting in way less condensate to worry about? Even if it's 85% efficient this way I'm happy to pay a little extra in fuel for the peace of mind of not having to deal with the ice buildup.

The other option I was also considering was getting a rain barrel and submersible pump that I can then manually drain monthly instead which would completely eliminate freeze ups.

Sorry if this sounds a bit scatterbrained. Pluming is not my background at all. If my assumptions are correct over the heating season instead of having to worry about 1000+ gallons of condensate icing up outside my garage I'm more likely to have to deal with around 200 ish gallons which is far more manageable. Does this sound right?

Thanks in advance to any of you that have insight 🙏🏻