My question is very similar to the one asked 6 years ago. I also have a Rheems 40 gallon gas WH (22V50F1), whose supply lines I'm replacing and relocating to another wall. The guy who put in the unit originally installed a U-shaped heat trap on each line, apparently following the manual, which says (very ambiguously):
The WH inlet and outlet both seem to have these heat trap nipples. Here's the figure from the manual showing suggested heat traps (6 inch minimum drop).
Because the lines will ultimately run up to the attic, these U bends require quite a bit of extra space in what is already a fairly tight installation. If I omit these U bends, and just connect flexible lines to the planned nipples at the wall (i.e., no U, just across the top of the heater and up), what is the downside, aside from (I assume) decreased efficiency? Is that any danger?
Heat Trap
For increased energy efficiency, some
water heaters have been supplied with
factory installed 3/4” NPT heat traps in
the hot outlet line and cold water inlet
line.
These heat traps may require a minimum
of one (1) 90° 3/4” NPT elbow and may
require an additional 90° 3/4” NPT elbow
or a 3/4” coupling depending on your
installation needs (emphasis mine).
For increased energy efficiency, some
water heaters have been supplied with
factory installed 3/4” NPT heat traps in
the hot outlet line and cold water inlet
line.
These heat traps may require a minimum
of one (1) 90° 3/4” NPT elbow and may
require an additional 90° 3/4” NPT elbow
or a 3/4” coupling depending on your
installation needs (emphasis mine).
The WH inlet and outlet both seem to have these heat trap nipples. Here's the figure from the manual showing suggested heat traps (6 inch minimum drop).
Because the lines will ultimately run up to the attic, these U bends require quite a bit of extra space in what is already a fairly tight installation. If I omit these U bends, and just connect flexible lines to the planned nipples at the wall (i.e., no U, just across the top of the heater and up), what is the downside, aside from (I assume) decreased efficiency? Is that any danger?