Got frozen pipes between the house & septic tank that wouldn't thaw out even after two days of warm weather?
Can't put an electric space heater in the septic tank because of possible methane gas presence?
Only have a 6" x 8" access hole into the tank?
No problem.
Take a clothes iron & bust all the plastic off of it. Bypass it's thermostat & direct-wire the heating element to the power cord so there's no spark from the thermostat regulating the temp.
Wrap the cord around a cinder block & position it so it hangs about 2 feet from the bottom of the tank (after it's been pumped out).
Set a porch swing cushion over the hole & weight it down with the concrete lid.
Wait 3 days & go flush the toilet.
My dad actually did it & didn't tell me. He did it like 3 days ago. We were barnstorming for ideas to thaw it out & that was one of my suggestions but I didn't really think it would work. It was just an idea that popped into my head because I made a heater for a dog house out of a clothes iron about 15 years ago.
One of my 5 gallon water jugs was left outside & it froze & I brought it in the house without noticing that the ice expansion had cracked the plastic. When it started to thaw out it made a puddle on the kitchen floor. I picked it up & carried it into the bathroom to set it in the bath tub while I put my shoes on to take it outside. I noticed the crap-water in the tub had gone down. I ran water for about 3 minutes & it went down. I turned on the water valve behind the toilet & flushed it 4 times & it went down fine.
So I got Mrs. Duck in the bathroom with her cell phone & went out to the septic tank with a flashlight. I was going to look in the tank while she flushed it so I could tell if the water was making it to the tank or just going into some underground cavity created by a leaking pipe. When I got out there I found the clothes iron heating element hanging in the tank & when I reached in there with the flashlight, I could feel it was like 100 degrees in there.
I called my dad & told him the clothes iron thing worked & we can call the rental place back & cancel that back-hoe.
I don't even know how long it took. I didn't even go in the bathroom at all yesterday since it's a useless room without working plumbing.
I'm thinking that the 240 volt baseboard heater I bought for my camper & never installed might've worked even faster though. It's long & skinny (shut up) and will fit through the hole (I said shut up) & it has no thermostat. It's designed for an external thermostat.