Pilot light won't stay lit. I hold the nob down for over a minute and the moment I let it go the pilot goes off. The flame seems to not come out as much as it used to last year. It used to come out c

SOURCE: wont run

check the flame detector it may be a millivolt generator or a flame rod feeding to an electronic circuit.

SOURCE: Pilot goes out after heating cycle

Check regulator on the unit.
Check pilot unit on the heater
use soapy water to check for leaks if see bubbles turn off main gas supply valve.
always turn off gas supply before any checks or repairs are made
when all else failes call your local gas provider to check heater and gas supply

SOURCE: pilot lights but when ignition pops back up the flame goes out

will either be the unitrol control box or the thermocouple, when you push down you are holding two magnets together and waiting for a small charge to be created from the probe in the flame , if this is not working you have no charge and the magnets won;t stick to allow the valve to open, change the thermo and see if that works first, its way cheaper than a new controler

SOURCE: Rinnai Tropic ventless heater. Pilot will light

found that the pilot tube had dust bunnys in mine so blew it out with a air can i had for the computer now the pilot light stays on just fine

SOURCE: pilot light wont stay on. How do you adjust pilot

then the pilot is blocked needs cleaning out or try blowing it out with air , or undone pilot and remove pilot injector and clean it .

Testimonial: "You were right. I blew out the pilot orifice and stove is working well. thanks"