1. #1
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    Default Effective ways to opperate pressure relief valves

    I was wondering what you guys would say would be a effective way to opperate a pressure relief valve. The reason i ask is because i am new to driving and pumping op's. I understand what it does and that if i run the pressure up to wear i want it to be as a maximum i would stop at that pressure and turn the vavle left (or lower) until the light comes on then go back to what my pressure is i am set. However i am asking because it seems like i am missing something or doing something backwards. even though we don't realy use it i would like to know that i am doing this right. Any help is greatly appriciated.
    (the reason we don't realy use it is because we only use two handlines off of the truck at 100 PSI at the nozzles.

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    That's the basic procedure I was taught and what I do. Most of the time our relief valve is set at or near the correct pressure, so not much adjustment is needed.

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    Default ????

    The reason you use it is for just that reason...you have TWO lines out. If one is shut down the pressure relief valve will take the pressure surge and relieve it. They put the pressure relief valves on there for a reason....use it. It's a safety device use it!!!
    Respectfully,
    Jay Dudley
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    Exactly as Jay said. Trust me you will not have time to reach up and throttle down if one of the hose lines is shut down quickly. I know they are supposed shut down slow....but you know how things happen.

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    We actually keep ours turned all the way down (recommended by our pump mfg.). It takes a bit of a dance between the throttle and the PRV, but it gets easier the more you do it. Crank the RPMs up until the pressure doesn't raise, then crank the PRV a few turns until the pressure doesn't raise, then vice versa.

    Practice, practice, and then practice some more.

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    We set ours at 150 lbs our usual PDP is 130 lbs for the preconnected 1 3/4" lines, and they are left in the on position. Each Saturday, we turn the valve all the way up and all the way down to exercise the spring in the valve. Then reset it at 150 lbs. D/O's will turn it down close to the pump pressure when more than one line is pulled.

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    Hope this helps clear it up for you...

    Set your pressure relief valve always, as a matter of good habit. To set it properly follow a routine such as i am about to describe.

    -Set your correct discharge pressure
    -Turn the relief valve down until you see your discharge gauge begin to drop (you'll also hear the sound of water as is "crackles" and flows through the valve).
    -Slowly turn the valve back up until the discharge gauge is at the original (desired) pressure.
    -Turn it about a half turn higher.

    This applies to the Hale relief valve. A waterous has an on off switch and I'll let their users chime in regarding any differences.

    By following a routine such as the one listed above, youve protected your pump and other lines/appliances from any water surges should the handline(s)/discharge(s) shut down abruptly.

    Think of the relief valve as nothing more than another discharge and the cap on it is a big spring. When your pressure gets too high, the valve opens and sends water back into the intake side of the pump. Some systems (HALE TPM) will also dump large water surges onto the ground if they are too substantial to relieve through the discharge side relief.

    Remember, the actual relief valve is on the pump body, the wheel you turn is attached to the pilot valve which is where the water pressure is sensed and sent to the valve to tell it what pressure it must open beyond.

    One of the most critical times for the relief valve to be set is in the transition from tank water to a pressurized supply (hydrant or nurse operation). Because your pump is making up all of the flow (pressure) on tank water. The introduction of the pressurized supply line to the pump will add to the existing pressure you already have set, causing an overpressure/flow situation. Without the relief valve, this overpressure will transfer to any nozzles, applioances, other discharge lines. The only way around this is to slowly open your intake while decreasing your throttle or gating the discharges, that can get tricky. Todays modern pressure governors compensate for this change of pressures during the transition as long as they are operated in the pressure (PSI) mode.

    In your example of two handlines, if one shuts down, that water (say 150 GPM or so) must go somewhere once the nozzle closes. Naturally it will want to seek the next availible outlet, which will be the other nozzle. The simplest analogy would be to use a garden hose setup off a wye from the spigot with the quarter turn shutoffs on each hose end. Flow both hoses at once. Expect fairly crappy results to be observed. Shut off one of the hoses at the tip and watch the pressure on the other tip increase. If you had a relief valve set for when both were flowing, that wouldnt happen (not as substantially).

    Theres no two better times to use the relief valve than when you are operaing more than one line or anytime you have a pressurized supply coming into the pump.

    Your discharge relief valve and pressure governors will not work if the discharge pressures are below the intake pressures.
    Last edited by MG3610; 12-17-2008 at 10:42 PM.

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    This is if you have a waterous pressure relief valve. Not sure if a Hale pump has the same setup or not.

    Make sure you keep that little screen clean. It is connected to the end of the round knurled knob on the PRV. Take it out weekly, and run it through running water from a sink, with good pressure. It will wash/rinse out any foreign material that it may collect. This will keep you and the nozzle guys happy.

    You said that you think, you are missing something. What do you think it is??

    For setting and testing for where you want it to open/operate, has been well posted, by others.

    FM1

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    We used to leave our PRV's "preset" and we had trouble many times. We had both Waterous and Hale, which were exercised weekly. We switched to no pre-setting and relieved the tension f the springs and most of the issues went away. I'd echo the screen cleaning issue on the Waterous PRV's, this is done weekly now to ensure they're clean.

    As MG and the others did well with the proper sequence, I'd note that none of them spoke about watching the lights. I was taught to watch the gauges and listen to the pump, as lights burn out.

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    One of the most critical times for the relief valve to be set is in the transition from tank water to a pressurized supply (hydrant or nurse operation). Because your pump is making up all of the flow (pressure) on tank water. The introduction of the pressurized supply line to the pump will add to the existing pressure you already have set, causing an overpressure/flow situation. Without the relief valve, this overpressure will transfer to any nozzles, applioances, other discharge lines. The only way around this is to slowly open your intake while decreasing your throttle or gating the discharges, that can get tricky.
    Great point MG. This was one of the evolutions we had to do as in pump operators class and also one of the evolutions I watch carefully if I'm helping a new operator. As you mention, very difficult evolution without the relief valve. You tend to either rob the line of water, or give the guys on the line too much pressure.

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    Guys, Thank you for the help..that makes alot more sense now. and far as thinking that i was missing a step, its simply the fact that i hav'nt done it enough, so it feels like i am possibly leaving something out. once again thanks for the help. i'll be working on the routine that was described by MG3610.

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    Don't go by the light, bulbs burn out all the time and wires can corrode. Go by your gauge(s) and the sounds (especially if the gauges crap out, it can happen).

    I put duct tape over the light when training pump operators.

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    Hale's manual: http://www.haleproducts.com/_Downloa...n%20Manual.pdf

    Waterous' website must be visited to get theirs.

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    Default Long post

    "I was wondering what you guys would say would be a effective way to opperate a pressure relief valve. ---------- However i am asking because it seems like i am missing something or doing something backwards. even though we don't realy use it i would like to know that i am doing this right. Any help is greatly appriciated.
    (the reason we don't realy use it is because we only use two handlines off of the truck at 100 PSI at the nozzles." - FFGodwin1217
    "One of the most critical times for the relief valve to be set is in the transition from tank water to a pressurized supply (hydrant or nurse operation)." - MG3610

    Practice, Practice & more Practice. You need to reach a point where you have trained yourself to listen to your engine... Throttle rpm, exhaust sounds, water sounds, the rattle of the drive line ... even when you are doing other things with your back turned, or hooking up, pulling ladders, your ears need to be hearing how the engine is responding to changes in load or water movement. The only way you can become the expert you need to be is to operate the equipment.
    Hale _ As recommended by others in this thread.....preset your pressure 20 psi above your normal beginning pressure for preconnects. For us that is 200 psi, since we normally operate our 1 3/4" hand lines with automatics at 180 psi discharge pressure. Once the first line is operating at the correct pressure, turn the wheel CCW (left) until you see the master discharge begin to drop. Do not twist rapidly, but turn down about a half turn every 5 to 8 seconds to allow the pilot assembly to adjust to the change. When you see the gauge begin to drop, turn the wheel a 1/2 turn to the right (CW) and you are set. DO NOT DEPEND UPON the LIGHT. I make one more adjustment to my pump... I set my master pressure at 190 psi, when the attack crew checks water flow before entering the structure, I choke back slightly on the valve for that line until my individual gauge pressure is about 180 or 10 psi lower than my master gauge. By doing this, you can tell when the line is taking water. (No flow pressure in master gauge and individual gauge are the same) You are your brothers keeper in this business. If the line is inside and the fire is building, but nobody is taking water, there is something wrong. Get the IC checking on what is going on inside.
    WATROUS - Keep the "football" handle turned all the way down (CCW) and the switch lever OFF. Run the throttle up until you are at the desired discharge pressure. Count the 1/2 turns you make in the clockwise direction. (Its easier to count half turns than full turns) If you want 130 psi as indicated in your post try about 19 .. 21 should get about 150 psi and for us 25 or 26 will get our 180 psi. You need to try this with your particular engine, but it should be pretty close to this setting. Once you have made the number of turns you think are necessary, turn the switch to the ON position and make the final adjustment the same as the Hale above about 1/2 turn at a time.
    With both types of PRV's, adding more lines will drop the pressure because more water movement uses more horsepower. When the pressure drops below the desired value, turn up the throttle just enough to reach your set pressure. Turning in too much throttle will simply open the PRV and waste the energy by circulating water through the pump. This can happen even when you have correctly set up the engine. Lets say you have 3 lines operating and your discharge pressure has dropped to 110 psi. When you turn up the throttle it is dialing in enough energy to supply all three lines. If one shuts down, the PRV will activate. This is what it is supposed to do. Dont turn down the throttle as long as there is a chance that all three can be operating at the same time. Turn it down when a line is broken up or is no longer in use.
    Words of caution when using a Watrous PRV ... The last step before shutdown and taking the pump out of gear should be to go to idle, turn the switch to off, then gently increase the throttle until the pressure reaches at least 100 to 150 psi. You are doing this to make absolutely sure that the Watrous PRV has the main valve completely closed. You can cause yourself a ton of grief by shutting down like this (DON'T DO IT) 1st - leave the switch on. 2nd - turn pilot setting down to zero. 3rd - take the pump out of gear. This will leave the main PR valve wide open, and because of the way Watrous operates, it might be difficult to get the valve to close. With this valve open, the best you can do is about 80 psi discharge pressure. The design needs a pressure difference across the pump to close the main valve, but you cant build it because the valve is wide open. This is a particular problem if you do not regularly exercise these valve and pilot assemblys. At least weekly or more often if you have minerals in your water.
    Transition from tank water to hydrant or relay supply. - Even with a PRV wide open there will still be about 50 psi across the pump. If the hydrant supply comes in at 120 psi, the engine will instantly reach 170 and the relief valve will probably be ineffective. Keep the intake gated back, or try switching a two stage pump to volume. This might seem counter intuitive, but in order to build pressure in parallel, you will need more rpm in the engine. This might help if you are also operating a hydraulic generator that needs higher rpm under electrical load. When working in a relay, we use five conditions for the engine at the hydrant / water source. 1 - out of pump gear using hydrant pressure only. 2 - 50 psi. 3. - 100 psi. 4. - 150 psi 5. - above 150 only on orders from the Water supply Officer or I.C. Minimize your radio chatter engine to engine, (Engine 13 from Engine 11 - condition 3) is all that is needed to get the proper set-up.

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