"Greg Hopp" wrote in message m...
Quoting from the installation instructions:
"Installation of this heater is a minor alteration and does not require a
Form 337 or STC , in accordace with FAR Part 43 Appendix B. It does not
require an A&P to install it, but the installation should be inspected and
signed off by an A&P..."

Partner and I interpreted this to mean an A&P signoff was NOT
required, just recommended. Is my Reiff sump heater installation
illegal without the A&P signoff?

The above text says that you don't need an IA to prepare a 337.
You need an log book entry on any maintenance or alteration.
Unless it's covered in the preventive maintenance exceptions
that has to be an A&P.