So I bought an adjustable pressure relief valve from Hardin marine. It's adjustable from 7-25 psi (I think that was the pressures...close to that). There are no instructions and no numbers or scale on it. How do I know what pressure it is set at? This is going on my chiller to prevent high pressure spikes from blowing my chiller apart. This water line is force fed thru a transom mounted pick-up. I can't turn the "adjuster" by hand...I don't want to ruin it but I guess use a pair of pliers? Also would turning it in raise or lower the psi it opens at? I emailed Hardin marine and received no reply. I would return it and by a different one somewhere else but I can't seem to find one at a price I can afford. Any help is appreciated

Not sure what one you have but if no response email call them. I'd assume turning in would raise pressure. To make sure it works as it should I'd adjust to lowest pressure and adjust up from there. Probably 12-15 pds where u wanna be I'd assume. Hopefully someone will chime in with same regulator.

I have never had one, so, I haven't done it. But, I do have a pressure gauge in my boat. My boat builds pressure while it is running reaching it's max at a specific rpm. Pressure is also determined by your pick up. So, I don't believe you could set it at idle like a fuel pressure regulator. More trial and error.

All regulators work on spring pressure.

Tightening (compressing) the spring raises pressure, loosening it lowers pressure.

You set it with a water PSI gauge

Mine (same as yours) turns by hand, but has quite a bit of resistance.

Ok. I think I got this. My only issue with setting it with my water pressure gauge is that if I come out of the water and it spikes when I come in and it happens to be set too high (since I have no idea what it's set to now) is it going to be too late?


Vintage chromoly-I guess I have week hands :-/ I'll try again, I'll have to put my man pants on!

Where do you have your relief discharge going? I would set it 1/4-1/2 turn past where its not dumping at speed.

Just pay attention to your psi gauge assuming u have one.

I have a PSI gauge. Also I'm putting the relief valve on the starboard front side of the chiller. This is all s*** I'm trying to figure out before I get my motor back. Hopefully that is soon. I don't want to get this motor back than have to figure this stuff out and wait on parts. I guess if wide open is 25 psi I can just give it 1/2 to a full turn and be ok. I'm gonna run a through hull fitting where I can turn around and see it to make sure water is flowing.