Reducing pressure without losing volume

Torque454

New Member
Ok so i know that i can reduce the pressure output of my unit by installing a larger tip. However, when the trigger is closed, that still pumps the system up to full pressure which for me is 4,000 psi. I need all the volume i can get, but i do NOT want to pump the system up to 4,000 psi. I am using a heater which the manufacturer told me had a schedule 40 coil in it and that they would not sell it to run with more than 2000 psi, but said it would take 8,000 before it would burst. He also said 3,000 would probably be alright but 4,000 he would never run through it. My research indicates the heater i am using actually has a schedule 80 coil in it so i don't know if i should believe the info i have found on websites (more than one) that sell this particular unit (Whitco Stinger 2) or if i should believe what the guy at the manufacturer said.

If its a schedule 80 coil it should be fine at 4,000 psi, even a schedule 40 coil is good for 4,000 psi according to this guy but he said he would never recommend it. Said it will leak sooner than normal. Anyways, in light of this i would like to never ever exceed 3,000 psi in the system, i don't think it will ever be necessary. I have a 3500psi relief valve (which doesnt seem to be working, i know ive exceeded 3500psi and it hasnt popped open yet) but the problem with it and most valves i have seen is that they all vent to the atmosphere. I would like it to vent back to the tank so i dont lose any water. I have found this valve: Water Cannon - Pressure Relief Valve MG1000 which looks promising. It appears to have a barbed fitting on it for a hose which i should be able to vent to the tank. Looks just like what the doctor ordered. What do you guys think? Will that valve be able to withstand opening and closing alot like the unloader will ?
 
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Torque454

New Member
I suggest you set the unloader at the desired operating pressure. Pop off
/ pressure relief valves are a safety back up and not intended to be cycled
like an unloader valve.

As far as a pressure relief valve I prefer the General Pump model
BAR3301 General Pump# 100723 w/barb
http://www.generalpump.com/PDFs/100723-Safety Relief Valve.pdf
Safety Relief Valve

That's what i was afraid of. Setting the unloader to 3,000 would theoretically drop 1gpm off my flow. I can either pump the system up to 4,000 psi, or suffer with 3gpm. Am i worrying too much about pumping up the system to 4,000psi (it will drop when the trigger is released due to the tip) or should I go ahead and turn it down? At some point i will upgrade all my components but i don't know how long it will be.
 

Oldtimer

New Member
Withe the proper size nozzle you can
run your machine at lower psi with full volume!

4gpm @ 4000 psi machine uses a #4 nozzle
a#6 nozzle would give you approximately 2000
PSI ..

If you just adjust the unloader you will bypass water.
 

Torque454

New Member
Withe the proper size nozzle you can
run your machine at lower psi with full volume!

4gpm @ 4000 psi machine uses a #4 nozzle
a#6 nozzle would give you approximately 2000
PSI ..

If you just adjust the unloader you will bypass water.

Yes i know, but what i am sayings is that i can get my pressure down by using a larger tip. BUT when the trigger is released, the system will still pump up to the maximum pressure set by the unloader. I have it set to allow for full volume and pressure. (4gpm @ 4000psi) but i really dont want that full pressure in my heater coils. I do however want all the volume i can get. I am probably worrying over nothing, 4k psi would probably be ok in the coils, but i just dont know. This hotbox was never intended to be run with 4k psi, altho the manufacturer said it wouldnt burst with that much pressure, but said it might leak sooner than it would othewise. That is why i wanted to drop it to 3,000 (size 5 nozzle) but still get full flow. 4gpm is not bad... but i need more, i certainly dont want any less.
 

Larry L.

PWN TEAM - Moderator Emeritus
The unloader has a return line to the pump,take it off the pump and plug the hole on the pump,run the return line on the unloader to the tank.
 

Torque454

New Member
Then change to a flow unloader, when you release the trigger, all pressure is gone from the hose and bypassed to the tank. I prefer the ZK1 General Pump K-1 Flow Sensitive Unloader

I wondered about this also but I was reading somewhere that you cant use a tip to regulate the pressure with a flow sensing unloader. I don't see why you cant though, as long as the tip was bigger than the minimum which is true for either style unloader. In that case there wouldn't be any loss of flow, just pressure. I guess I should have asked that on here before I went off chasing another alternative.
 

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