Venting my Rheem with horizontal 3'/5' concentric

I am venting my 3'/5' concentric vents horizontally for my new tankless. I admit I was an idiot for doing this, but I already cut the hole in my basement wall, and purchased the horizontal vent kit, but it turns out that the vent now terminates halfway below ground level. Is there any way to make this ok, without having to cut a new hole? I could dig a little hole for it like a window well, and install drainage tiles to ensure it doesn't fill up with water (my house is uphill). Another, more expensive option would be to buy more sections of vents and run them up the exterior of my wall then out away from the house with the 4 degree slope.

Are either of these solutions viable or did I screw myself when I made that hole?

Any advice would be extremely appreciated.

In Minneapolis, I assume you get considerable snow. You need to to terminate your vent above expected snow levels.

joemcl said:

In Minneapolis, I assume you get considerable snow. You need to to terminate your vent above expected snow levels.

Click to expand...

Does that mean higher than the snow will ever get? And what is the reason for this? I assumed the snow would melt, and since there is a 4 degree slope, the melt wouldn't go up the exhaust. Anyways, I will take your word for this.

I have also discovered that once I go horizontal, I am not allowed to go vertical after that.

Guess I am going to have to make a new hole and patch up the old one...

Even with sealed-combustion units you can't safely vent them into snow. With high levels of combustion exhaust contaminant in the intake air combustion air has lower & lower oxygen levels, and starts putting out copious quantities of carbon monoxide as it becomes buried in snow before the burner controls detect an error condition. This isn't merely theoretical- people have died from this with condensing boilers buried/partially buried in snowdrift. While with hot water heaters it's less likely to kill, given the intermittency of hot water draws, it still should be taken very seriously.

It seems it would be really hard to put it high enough that snow levels reaching it would be an impossibility. Could this potentially fatal situation be averted with a carbon monoxide detector near the water heater?

Maybe,maybe not, but it would still be a code violation in most places, and as the installer you'd be liable for anything that happened.

It's just not worth going there- do you really want to be the guy telling the emergency services (while you're all standing out in the snow freezing your butts off while airing the house out), "The CO alarm went off, and hey, it didn't actually KILL anybody!" ???