Pressure relief valve...how do you set it?
 

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.

Always good thinking ahead. What is max psi on chillers? Glad to see you putting relief valve on. Anything from here on out I am running also. Even without chillers. To much water pressure not good on anything.

I run 2 of them, turned all the way out still have 23 psi, can't get mine any lower.

Do you have them plumbed before or after the chillers ?

After? What would that accomplish?

Not sure of the max pressure. I think 25-30 is max. I don't run one on the engine but I'm using a merc single stage pump (this time). That's what comes on stock motors so I didn't really see a need. Last year I ran a 2 stage pump and wasn't getting any more than 7-8 psi in the engine or chiller. Never ran warm tho. In fact it ran cold and I had to do an oil thermostat. Still took 45 mins at 3500 rpm to get oil temp to 180. Water temp is always 145ish

Benjen....people seem to have different opinions on where the relief valve should go but why does it matter? If the relief valve is after the cooler would the pressure be that much different before the cooler? I would think that the pressure would be similar throughout. Also Hardin marine sells a thru hull fitting/dump that is also a pressure relief valve all in one. That would obviously place the valve way after the cooler. I'm certainly no engineer tho

I don't know what to say. Maybe it's me/my boat. After the chiller in my boat, and I thought everybodies boat, but maybe not, the water dumps overboard. So, what pupose would the regulator serve than. Plus isn't the concern about the pressure in the chiller core? Which again what purpose would the regulator be exiting the chiller?

I have no idea either. I have the Teague plumbing diagram that someone shared with me on this site and I'm following that(sorta). So I'm putting mine on one of the water intake ports....so before the chiller as well. A lot of it doesn't make sense to me. I just hope it all works because I'm broke now

I would assume that there would be some pressure drop across the chiller, so after the chiller could be set at 20 psi, but the input pressure may be higher. My boat didn't have them, but if I had added them, in front of the coolers for sure.

You own a boat...........so of course your broke.

Some regulators are designed to set psi before them.

Some regulators are designed to set pressure after them.

One needs to find out from the manufacturer on how it is designed.

Color me stupid. If the water coming out of the chiller goes overboard, as I suspect it does what is the regulator doing after the chiller?

I put mine in the sea strainer feeding the chiller. My thoughts are that if you put it after the chiller, the core still gets the initial pressure spike that opens the valve. If you put it before the chiller, that pressure spike should be under control before it hits the core.

Snapmorgan........that definitely makes sense to me...but I'm no engineer!

If it is a regulator that maintains psi before the regulator, it is creating pressure in the chiller and everything before it.

Same circumstance as above,If it is a regulator that maintains psi after the regulator...well, the regulator doesn't want to open and let water passed it because you will not make any psi (resistance) passed it by dumping ater in the atmosphere...until you reach the max psi of the regulator hich will force it open and let water out.

Think about fuel systems. A dead headed carb system with a high psi pump will have a regulator before the carb to reduce the psi to one that the carb can handle. This regulator sets psi after the regulator.

A return style commonly used in EFI will have a regulator after the injectors. It send unused fuel back to the tank with little or no psi. This regulator regulates the psi before the regulator.

Anyway, I'm not trying to complicate things and some things easier to explain in person vs computer.

I'm ust trying to make sure those with psi issues and using a regulator don't have it installed / rigged incorrectly.

Maybe if those that don't understand my ramblings and want to really know, google psi regulators and how they work.

It can be kind of tough to learn the concept, but it is easy enough once you 'get it' you get it and are all set from there.

I'm gonna drink beer! :ernaehrung004:

What psi is your tap regulators set at ? :)

45 :cool-smiley-011:

I usually run around 35-40lbs on my setup, my opinion is that it's high but my mechanic says it's fine lol what could be causing the restriction? Thermostat? Closed cooled system, scx drive.

Install it so it is schematically parallel to the inlet of the chiller.
Even if they were to put it on a test bench and set it to 30 PSI for example, we must remember that the pressure range it is advertised as having is the delta from the inlet to the outlet. Certain installations may offer different backpressure on the outlet. This is why putting a pressure scale on the valve wouldn't be accurate for certain installations. You must also make sure that the valve has enough flow capacity for the application.
Another approach would be to install it in series on the outlet of the chiller. This would hold pressure in the chiller any time the engine is running. This is a bit more risky and is not fail-safe incase the relief valve sticks. If you are looking to protect against pressure spikes, an accumulator installed in parallel to the feed line would be a much better choice.

Jeff

Regulated leak in the system.

I just added pressure relief valves to my set up. I went with the Hardin valves that are incorporated into the thru-hull fitting, they are preset at 10 lbs. Mine is in an NA application and are mounted between the oil cooler and the engine. I've yet to run them, so no clue what the actual pressure is.