I just wanted to add my experience to the first thread that comes up when someone searches for "fermentap regulator"
First: Mine was blowing out the relief valve at 25psi as well. I had already seen this thread but sent an email to morebeer asking wtf the deal is. Without further discussion they apologized and sent me a taprite regulator gratis. Kudos to morebeer / moreflavor for stellar customer service.
As far as the pressure relief valve is concerned, it's a standard air compressor type popoff valve. If you have a big flathead screwdriver with a notch in it, you could take it apart and shim the spring until it opens above your desired force carb level. Just like delaying the waste gate valve on a turbo charger.
But these things cost $7, and i didn't feel like finding a big screwdriver and notching it, so i just bought a 1/4" NPT RH threaded 60psi popoff valve from an ebay vendor. Not a big deal at all. If you weren't concerned about the safety aspect you could just get the 135psi version at Lowes or Home Depot in the air compressor department. Or install a plug. But don't do that.
fwiw, you don't see thread sealer or teflon tape on these because all of the ports have teflon washers in their bases. This is not a bad idea at all, provided that everything is properly torqued down.
Also, the nylon washer built into the tank connector does work just fine. Or you can use an additional nylon washer if you wanna.
Anyway, yeah, i bought a new popoff valve and thought, "hey, free regulator!" - which works fine for me because by happenstance I have two 20lb co2 tanks (one of which came with a low-end regulator) and I'm working on a smaller tank system for a very small mini-fridge.
Not that i need two 20lb tanks, but i'd like to sweeten the deal with a perfectly serviceable regulator when i sell the steel one.
Anyway, i went to test the new popoff valve and something was hissing. After making sure everything is tight, i got out the spray bottle of star-san and started spraying threads.
The cga320 nipple - the pipe that connects to the tank - leaks at the regulator.
And they used red thread locker on it.
I'm going to have to put the body in a vise and use a pipe wrench to get it out, and I've done some pretty good damage to it trying lesser methods.
fwiw, all of the low pressure side ports are RH thread, both of the high pressure side ports are LH thread.
But hey, free regulator, right? less $7 popoff valve, and the $10 I'm gonna spend on another cga320 nipple. and the time investment.
These are not bad regulators. They had some good ideas, but the final implementation was not that great. The popoff valve was selected wrong or is defective, and whoever assembled them started with bad directions.