Any issue with 45 elbow down on Cat IV vent termination

[Ross Neag]

My fear would be, potentially, frost closure on the vent. We typically on see straight terminations, vertical, or 90 to 90 outward and horizontal.

This is 2012 Rheem 94% single stage, can't find on their site. Thanks

[Markus Keller]

I don't have an issue with a 45 on the end. I don't remember seeing a restriction for 45's in any install guides. I've found 90's ice over more. Fairly standard practice. Often times a 45 can work a bit better than a 90 or straight end in terms of directing discharge; especially in Chicago gangways.
As far as finding the info on the Rheem site, probably not. Rheem and (others) have changed their sites from all encompassing to consumer feeds. Getting the technical data you want nowadays means registering on many sites.
On the old Rheem site the install guide was a readily downloadable PDF, now you have to register to access lots of that type of info. The end termination specs are part of the install guide which comes with the furnace.
Google the model # itself, sometimes the install guide will pop up using that.

[Bob Elliott]

Following is from NORDYNE install manual


Improper
vent termination can cause recirculation
of the fl ue gases. This may
result in furnace vibration. In severe
cases, the furnace will cycle due to
the intermittent contact between the
fl ame and the fl ame sensor. If you
note oscillations occurring, check the
vent confi guration. Make sure that
the exhaust vent does not have a 90
degree termination.

Vent Pipe Installation
Pipe Routing and Support
Route piping as directly as possible between
the furnace and the outdoors and remember
that routing affects pipe size requirements per
the preceding section. If a two pipe system is
used, locate the combustion air intake and the
vent exhaust in the same atmospheric pressure
zone - i.e. both must exit the building though the
same portion of exterior wall or roof (See Figure
22). Vent piping must be sloped upwards not
less than 1/4” per foot in the direction from the
furnace to the terminal. This is to ensure that
any condensate fl ows back to the furnace (where
it can be disposed of through the condensate
disposal system).