Announcement

Collapse

Firehouse.com Forum Rules & Guidelines

Forum Rules & Guidelines

Not Permitted or Tolerated:
• Advertising and/or links of commercial, for-profit websites, products, and/or services is not permitted. If you have a need to advertise on Firehouse.com please contact sales@firehouse.com
• Fighting/arguing
• Cyber-bullying
• Swearing
• Name-calling and/or personal attacks
• Spamming
• Typing in all CAPS
• “l33t speak” - Substituting characters for letters in an effort to represent a word or phrase. (example: M*****ive)
• Distribution of another person’s personal information, regardless of whether or not said information is public knowledge and whether or not an individual has permission to post said personal information
• Piracy advocation of any kind
• Racist, sexual, hate type defamatory, religious, political, or sexual commentary.
• Multiple forum accounts

Forum Posting Guidelines:

Posts must be on-topic, non-disruptive and relevant to the firefighting community. Post only in a mature and responsible way that contributes to the discussion at hand. Posting relevant information, helpful suggestions and/or constructive criticism is a great way to contribute to the community.

Post in the correct forum and have clear titles for your threads.

Please post in English or provide a translation.

There are moderators and admins who handle these forums with care, do not resort to self-help, instead please utilize the reporting option. Be mature and responsible for yourself and your posts. If you are offended by another member utilize the reporting option. All reported posts will be addressed and dealt with as deemed appropriate by Firehouse.com staff.

Firehouse.com Moderation Process:
Effective immediately, the following moderation process will take effect. User(s) whose posts are determined by Firehouse.com staff to be in violation of any of the rules above will EARN the following reprimand(s) in the moderation process:
1. An initial warning will be issued.
2. A Final Warning will be issued if a user is found to be in violation a second time.
3. A 3-day suspension will be issued if the user continues to break the forum rules.
4. A 45-day suspension will be issued if the user is found to be a habitual rule breaker.
5. Habitual rule breakers that have exhausted all of the above will receive a permanent life-time ban that will be strictly enforced. Reinstatement will not be allowed – there is no appeal process.

Subsequent accounts created in an effort to side-step the rules and moderation process are subject to automatic removal without notice. Firehouse.com reserves the right to expedite the reprimand process for any users as it is deemed necessary. Any user in the moderation process may be required to review and agree to by email the terms and conditions listed above before their account is re-instated (except for those that are banned).

Firehouse.com reserves the right to edit and/or remove any post or member, at any time, for any reason without notice. Firehouse.com also reserves the right to warn, suspend, and/or ban, any member, at any time, for any reason.

Firehouse.com values the active participation we have in our forums. Please ensure your posts are tasteful and tactful. Thank you very much for your cooperation.
See more
See less

Pressure Governor Help

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Pressure Governor Help

    Hello. I am new to the forums and am beginning to learn pump operations. I'm having some difficulty with pressure governors and how they work. Specifically in regard to "pressure" vs. "RPM". What is the difference and when would you want to use one versus the other. 2 members tried to explain it but they contradicted each other, with starting in either, for example setting your pressure then switching to RPM to regulate the pressure like a relief valve. Hope that makes sense and thanks to anyone who can help me out.

  • #2
    Rpm/psi

    In a nutshell: RPM mode is an electronic throttle only, which regulates the engine speed. If you are in pump, it will increase/decrease your discharge pressure, but will not compensate for lines being opened/closed. Not what you want selected for safety reasons when pumping handlines.

    PSI mode uses a pressure transducer on the discharge side of the pump to tell the electronics how much RPM is needed to maintain a set pump pressure, using the cruise control segment of the engine's ECU. This allows the pump pressure to remain at the set pressure when lines are opened/shut during operations. You should always operate in PSI mode on a fireground with handlines deployed.

    When drafting, you need to start in PSI mode until water is established, because if you start in PSI mode, the safety feature in the governor will sense no water pressure and return the engine to idle.

    I believe Class 1's website (Hale IDEX) has a video clip showing how their electronic governor works.

    Comment


    • #3
      Originally posted by HFD147 View Post
      In a nutshell: RPM mode is an electronic throttle only, which regulates the engine speed. If you are in pump, it will increase/decrease your discharge pressure, but will not compensate for lines being opened/closed. Not what you want selected for safety reasons when pumping handlines.

      PSI mode uses a pressure transducer on the discharge side of the pump to tell the electronics how much RPM is needed to maintain a set pump pressure, using the cruise control segment of the engine's ECU. This allows the pump pressure to remain at the set pressure when lines are opened/shut during operations. You should always operate in PSI mode on a fireground with handlines deployed.

      When drafting, you need to start in PSI mode until water is established, because if you start in PSI mode, the safety feature in the governor will sense no water pressure and return the engine to idle.

      I believe Class 1's website (Hale IDEX) has a video clip showing how their electronic governor works.

      We just had our delivery class last Saturday on our new engine. Your explanation is almost word for word to what we were told and shown.

      Comment


      • #4
        MODES OF OPERATION

        POWER ON - When the unit is first powered up, the display will show [MODE] and the engine will remain at idle until the mode switch is pressed to select the desired operating mode, PRESSURE or RPM. If the pump is engaged and the OK to Pump LED is illuminated, PRESSURE will be the first mode selected otherwise Throttle will be the first mode.

        RPM MODE - When the unit is in RPM mode, the display will read “THROTTLE” and the green RPM LED will be illuminated. Engine speed is controlled by the INCrease and DECrease switches and the display will indicate “INCREASE” or “DECREASE” as appropriate when these switches are depressed. The governor will maintain the last output signal attained with these switches. The engine will maintain an RPM appropriate for the throttle signal being sent.

        Note: if while operating in rpm mode the pressure increases more than 50 psi from the pressure logged at the last switch press, the governor will limit the pressure increase to no more than a 50 psi differential. The governor may reduce engine rpm to achieve this and the message psi limit will be displayed in the message center. Note: the governor will not attempt to regulate pressure in this mode, only limit the differential pressure to 50 psi from the pressure present when the last switch was pressed.

        PRESSURE MODE - When the unit is operating in the Pressure mode, the display will show “PRESSURE” and the PRESSURE LED will be illuminated. Pump pressure is set by using the INCrease and DECrease switches. The governor will attempt to maintain the last pressure achieved with these switches. The display will indicate “INCREASE” or “DECREASE” as appropriate. The governor maintains pump pressure by controlling engine RPM in response to a signal from the pressure transducer mounted on the pump. When controlling in this manner, the display will show CTRL DEC or CTRL INC. Switching between modes by pressing the mode switch will change the governor from RPM to Pressure mode without a significant change in engine speed or pump pressure. The message center will indicate “PRESSURE” or “THROTTLE” as appropriate once the mode change has been made. When switching to PRESSURE, the pressure set point is whatever pressure is on the transducer at the change.

        PRESET MODE - Pressing the PRESET switch in either mode will control the engine to attain the preset RPM or pump pressure programmed in governor memory. If there is more than 10 PSI pressure on the pump, the RPM Preset is disabled. If the Preset Switch is pressed, DISABLED will be displayed momentarily.

        HIGH IDLE MODE - An input is available to bring the engine speed to a PRESET RPM (High Idle) from a remotely mounted switch. While operating in this mode, the display will show “HIGHIDLE”. This function is inoperative when the pump engaged input is active, there is more than 10 PSI on the pressure transducer or if the MODE switch on the governor has been pressed. Pressing the IDLE switch causes the high idle to drop out and the high idle input must be toggled off and then on again to reinstate high idle. The INC and DEC switches are active in high idle mode and the engine speed can be adjusted, changing engine speed in this manner will not change the preset RPM that is set in memory.

        IDLE MODE - Pressing the IDLE switch at any time returns the engine to idle speed.
        NOTE: A FIRM, POSITIVE SWITCH DEPRESSION IS NECESSARY TO ACTIVATE THIS FEATURE AND A QUICK PRESS MIGHT BE IGNORED.

        CAUTION SENSOR - Whenever the transducer signal is below 0.3 VDC or above 4.8 VDC, a sensor fault will be logged and SENSOR will be displayed in the message center. (SENSOR will flash if the failure occurs while operating in PSI Mode) Once a failure is detected, the governor can no longer maintain a pressure setting. It will hold the current engine RPM and only operate as a throttle. Once the SENSOR message is displayed, it will not clear until power to the governor is reset. It is extremely important that the cause for this message is investigated. The governor cannot control discharge pressure properly unless the sensor signal is reliable and correct.

        SWITCH SESSION PRESSURE - If the INC switch is held the governor will not allow a change greater than 80 PSI without releasing the INC switch and pressing it again. This is only applicable when the pressure is above 90 PSI. This prevents high pressures from being introduced by a distracted operator.

        PRESSURE / WATER LOSS - If the discharge pressure drops below 30 PSI for any reason, engine speed will not be increased. The governor output voltage will reduce to the last known value (engine RPM) where the pressure set point was obtained. The display will flash -INTAKE- during this low pressure condition. If the pressure increases above 30 PSI, OPERATOR will flash and the governor will not increase output unless the operator presses the INC or PRESET switches. If pressure above 30 PSI is not regained within 5 seconds, the governor will return the engine to idle and display LoSupply. The operator must make certain that the water supply is adequate and then reinstate governing using the MODE, INC and/or PRESET switches.

        PRESSURE RECOVERY / CAVITATION (TRIM) - The governor has a trim adjustment, this can be set between 5% and 20% of maximum throttle. This parameter limits the governor’s maximum increase in a pressure recovery attempt. The message center will flash OPERATOR when this limit is reached and the RPM will not increase further. The operator must take positive action to restore discharge pressure. If pressure is not restored within 4 seconds, the governor will reduce output to the last known output where pressure was maintained. The operator must input a new set point with the INC/DEC or PRESET switches. If the pressure rises above the original set point and the governor decreases the engine speed, the governor will resume normal governing operations.

        PSI ENABLE - The pressure governor will not control pressure until a discharge pressure of 70 PSI is attained. It will act as a throttle until this pressure point is achieved.

        RPM PRESET DISABLE - If there is pressure on the pump transducer, RPM Preset is disabled and a DISABLED message will be displayed in the Message Center if you try to use the preset button in the RPM Mode.

        PRESSURE PRESET - While the governor is attempting to reach the preset PSI, the increase is tested at intervals and if the pressure is not increasing, the governor will maintain the engine speed at the point the pressure stops increasing and uses that as the pressure set point.

        HIGH IDLE - The High Idle feature is disabled if there is less than 10 PSI at the pump transducer.

        SWITCH SESSION PRESSURE – If the INC switch is held and the operating pressure is above 90 PSI, the governor will not allow a change greater than 80 PSI without releasing the INC switch and pressing it again. This is to prevent high pressures from being introduced by a distracted operator.

        MESSAGES – OPERATOR will flash anytime the governor can’t achieve a desired pressure.
        This indicates that the governor will not increase engine speed until the pump operator intervenes.
        INTAKE- will be displayed anytime the governor is operating in pressure mode and the discharge
        pressure drops below 30 PSI. If pressure remains below 30 PSI, the display will change to LoSupply and engine speed will be reduced to idle. At this point, the operator must correct the supply or discharge problem and reinstate governing OPERATOR will be displayed anytime the governor can’t achieve a function or pressure. This indicates that the governor will not increase engine speed until the pump operator intervenes. CTRL INC will be flash in the display if the governor cannot regain the set pressure. It will change to OPERATOR (flashing) if pressure cannot be regained within 4 seconds. During these periods, the governor will not command an increase in engine speed and will return to the last known engine speed command where the set point was achieved.

        PUMPING OPERATION EXAMPLES

        OPERATION 1 - Tank Supply for pre-connects or small diameter hose.

        Upon arrival at the scene, position the apparatus and shift into pump gear using department SOP. At the pump panel, the three interlock LED’s must be ON. and the governor Message Center should display [MODE]. If the Throttle Ready Interlock is not present, NO INTLK will be displayed in the message center when the MODE switch is pressed and the governor will not respond to an increase or decrease request. The governor will check for a valid pressure transducer signal at power up, if none is found, SENSOR will be displayed. If this is the case, the governor will operate as a throttle only. It cannot react to pressure changes. The MODE switch must be depressed to select a governing mode.

        Ensure that water is available to the pump by checking the Master Discharge Gauge for pressure. Prime the pump and establish water prior to pressing the governor Preset Switch. Once pressure mode is selected, the PRESET switch may be depressed to quickly bring the pump up to the preset operating pressure. The governor will respond to increase and decrease commands from the INC and DEC switches within the operating capabilities of the engine. When the INCrease switch is pressed, INCREASE is displayed in the message center. When the DECrease switch is pressed, DECREASE is displayed. Whenever the governor adjusts the engine speed to maintain the established RPM, CTRL INC or CTRL DEC will be displayed while the governor is actively adjusting engine speed to maintain the set point.

        The message center will display: THROTTLE or PRESSURE to indicate the current operating mode. Whenever operating with a limited water supply, always be aware of the possibility of running out of water. When the governor is operating in pressure mode it will attempt to recover from a discharge pressure loss and increase engine RPM to compensate. If water is introduced to the pump while the engine RPM is advanced, a pressure spike will result. The magnitude will be a factor of pump speed and water quantity. It is not uncommon to lose water and regain it during operation with extremely low water levels due to the position and configuration of the tank sump.

        OPERATION 2 - Transferring from tank to pressurized water source.

        The transition from tank to hydrant or relay is an operation that needs to be approached with
        awareness. Resultant pressure with no change in pump speed is a combination of the operating
        pressure prior to the change plus the incoming pressurized supply. If operating at 125 PSI and
        adding a 100 PSI pressurized water source, the resultant discharge pressure will be 225 PSI.
        The governor will compensate, but it will not be instantaneous. Any time the pump receives air or
        an air-water mixture, the discharge pressure will drop and the governor operating in pressure
        mode will increase pump speed to maintain the set pressure. Every effort should be made to
        purge or bleed air from the system. When pressurized water hits the impeller, a significant pressure
        spike can occur. This may be an occasion to change the governor to RPM MODE before the
        changeover, establish an adequate supply and then switch back to pressure mode. In some
        instances, a decrease in RPM would be in order and then the PRESET switch can be used after
        switching back to pressure mode to re-establish pressure governing.

        OPERATION 3 - Transferring from tank to draft

        The transition from tank to draft is another scenario that requires a knowledgeable operator/
        engineer. A positive water supply must be established prior to changing the water source. If this
        is not accomplished, the governor will increase pump speed and when the supply is established,
        the pressure will be more than desired. If the engine RPM increases dramatically, press IDLE,
        establish the water supply, press MODE and then PRESET to return to pressure governed
        operation. The total time should be less than 3 seconds.

        OPERATION 4 - Portable Tank (Pond)

        The transition from onboard tank to portable tank is a tank to draft operation. When the portable
        tank is refilled is a time when the pump operator must control the situation. When the tank gets
        low, air can be introduced into the system. The operator must control this so that a pressure
        spike is not introduced. When the tank is refilled from a dump, a wave action can be set up that
        would allow running away from water for a short period of time. This can be controlled by switching to RPM mode temporarily while the tank is refilled.

        Comment


        • #5
          Great explanation. Trying to explain the operation of a pressure governor to students sometimes is not the easiest of explanations. Thanks to HFD for giving me a even easier way to describe it to my students.

          On my engine, a 93' Pierce with a waterous pump, our pressure governor has a toggle switch for increase/decrease and a toggle switch for throttle/pressure. We were told on delivery to start in throttle, get our pressures set and then switch to pressure. I'm not exactly sure why, I wasn't on the job here when we got it, but I've started in pressure and its works the same.

          Our other apparatus is a mix of class 1 and pro-s governors and pressure relief valves.


          HFD...I think you had a typo....but if I am correct you meant to draft you start in RPM.

          Comment


          • #6
            Originally posted by HFD147 View Post

            When drafting, you need to start in PSI mode until water is established, because if you start in PSI mode, the safety feature in the governor will sense no water pressure and return the engine to idle.

            I.
            Wouldn't that be start in RPM mode

            Comment


            • #7
              Originally posted by ALSfirefighter View Post
              On my engine, a 93' Pierce with a waterous pump, our pressure governor has a toggle switch for increase/decrease and a toggle switch for throttle/pressure. We were told on delivery to start in throttle, get our pressures set and then switch to pressure. I'm not exactly sure why, I wasn't on the job here when we got it, but I've started in pressure and its works the same.
              Gotta wonder what engine you have in that Pierce. Is it possibly a 2 cycle Detroit (71 or 92 series), mechanically controlled as opposed to electronic. Pierce had be using their "version" of a Barber-Colman governor on some of them, and they're set up with switches just as you describe. There are a number of them in our area. If you look at the control and compare it with the B/C, the only difference is the name on it.

              We have a B/C on our '89 Duplex/Quality. Any time you switch from Throttle mode to Pressure mode or vice-versa, it returns to idle and you have to start over. That's the way B/C designed it to work. I don't know what the Pierce "version" does, but I wouldn't be surprised if it's the same.

              With the electric motor driven primer on our Waterous CMU pump, my practice has been to leave B/C alone until I establish a prime. Then I normally go to Pressure mode and set my discharge pressure. If I was awake enough at the start and put the transfer valve in Volume before priming, I'll switch it back to Pressure at that time also unless I'm in a situation that calls for remaining in Volume. Seems to work quite well.

              Side notes: Even though priming a two stage pump in Volume is considered preferable, I've never had a problem doing it in Pressure. That goes for our '78 Hahn with a Hale QLD 1250 also.

              The Hale originally had a rotary gear primer driven by an intermediate gear in the transfer case. You had to throttle up in order to prime with it. Some years ago the gear primer froze up (a whole 'nother story), so I replaced it with an electric one. Since then, it too primes at idle.

              Stay safe out there, everyone goes home!

              Comment


              • #8
                OOPSi

                Good catch by both of you.......it should have read when drafting to start in RPM, then switch over when water is established.

                You both pass my (unintentional) test!

                Comment


                • #9
                  Chief:

                  Ours when you switch from throttle to pressure does not return it to idle. I will look up the B/C. I know Pierce used everyone else's components with their name on it. I've also have drafted with a 2 stage pump in pressure as well during training. The few times I've done it for fires I've always gone pressure, like as you said due to the gpm's involved in supply. I am all hydrants but commerical/industrial complexes right on a large river, great water supply when needed.

                  Comment


                  • #10
                    You might take a look at Fire Research's website. They have interactive manuals on their website. I prefer their InControl governor as I think it's the easiest to operate and it includes master intake and discharge pressures.

                    Check out this link here.
                    http://www.fireresearch.com/ietm/FRC.htm

                    Click on Interactive Manuals and then the InControl.

                    Comment


                    • #11
                      Originally posted by toddmcbr View Post
                      You might take a look at Fire Research's website. They have interactive manuals on their website. I prefer their InControl governor as I think it's the easiest to operate and it includes master intake and discharge pressures.

                      Check out this link here.
                      http://www.fireresearch.com/ietm/FRC.htm

                      Click on Interactive Manuals and then the InControl.
                      I like the layout of the InControl unit very much. But we went with the Pump Boss because the C13 Cat engine runs the newer, faster and much more capable SAE J-1939 data bus. The InControl runs the older J-1587 bus.

                      Last time I spoke with anyone at FRC I got the impression that they were not going to upgrade the InControl any time soon. That may have changed by now, but since our engine is nearing completion, we were unable to wait it out. The Pump Boss appears as if it will do a very nice job also.

                      Stay safe out there, everyone goes home!

                      Comment


                      • #12
                        Originally posted by chiefengineer11 View Post
                        I like the layout of the InControl unit very much. But we went with the Pump Boss because the C13 Cat engine runs the newer, faster and much more capable SAE J-1939 data bus. The InControl runs the older J-1587 bus.

                        Last time I spoke with anyone at FRC I got the impression that they were not going to upgrade the InControl any time soon. That may have changed by now, but since our engine is nearing completion, we were unable to wait it out. The Pump Boss appears as if it will do a very nice job also.

                        Stay safe out there, everyone goes home!
                        I agree with you on the pump boss. I've used them a few times and I do like them as well. The only draw back is you have to add your (2) 4.5" Master Gauges on the pump panel where as the InControl it is all included.

                        Obviously that wouldn't work in your situation and you ended up doing the same thing I would have done if I were speccing out another truck.

                        Stay Safe!

                        Comment


                        • #13
                          Any one had any problems with the engine idling down when you open a nozzle? Went interior on a house with an 1-3/4" selectable gallonage nozzle @ 125 gpm, found the bedroom that was on fire, opened the nozzle and it went limp. Im sitting there with the fire starting to roll across the ceiling and a limp nozzle flinging water at it until my E/O runs back to the pump panel (he had been hooking up to the 2nd in engine). Everything turned out ok but we have tried to replicate it with 1-3/4" nozzels, and 2-1/2" nozles but we cant get it to do that. Someone mentioned that the computer in the truck will idle down if it thinks a hose line burst, but like I said we cant replicate it, and there is nothing in the literature from the manufacturer about it. By the way its a Stuphen 1500/1000 with a hale pump.

                          Comment


                          • #14
                            Originally posted by DelSol View Post
                            Hello. I am new to the forums and am beginning to learn pump operations. I'm having some difficulty with pressure governors and how they work. Specifically in regard to "pressure" vs. "RPM". What is the difference and when would you want to use one versus the other. 2 members tried to explain it but they contradicted each other, with starting in either, for example setting your pressure then switching to RPM to regulate the pressure like a relief valve. Hope that makes sense and thanks to anyone who can help me out.

                            DelSol,

                            The posts by CE11, HFD147, and Tomwnh, been right on!

                            CE11,

                            I to like the FRC INControl, though I am a bigger fan of the Fire Commander! I also prefer the Detroit over Cat's and Cummings for Governor operations.

                            Who is the Pump Boss made by? Never heard of them.

                            HFD147,

                            Excellent answer in a nutshell.

                            Tomwnh,

                            I agree with everthing you wrote except for:

                            "OPERATION 2 - Transferring from tank to pressurized water source.

                            Resultant pressure with no change in pump speed is a combination of the operating
                            pressure prior to the change plus the incoming pressurized supply. If operating at 125 PSI and
                            adding a 100 PSI pressurized water source, the resultant discharge pressure will be 225 PSI."


                            Having worked for the 5+ years now with a Fire Commander I prefer to have it in the Pressure mode for the reason you stated. If you are in the RPM mode operating at 125 PSI and you add a 100 PSI off the hydrant the resultant discharge pressure could be in excess of 225 PSI. Where if you are in the PSI mode the Governor will sense the increase in pressure and drop the RPM's to try and maintain the 125 PSI the Governor was set for. Yes it can only go as far as engne idle, so the guys on the hand line could still see and increase in pressure however it will be far less then the 225+ PSI they would see if operating in RPM mode.

                            Comment


                            • #15
                              [QUOTE=Chief1FF;780518]DelSol,

                              Who is the Pump Boss made by? Never heard of them.

                              Chief, Pump Boss is a later product of Fire Research Corp. You can see it on their web site. As with InControl and several of their other products, they have an interactive manual available at the site. Check it out!

                              Stay safe out there, everyone goes home!

                              Comment

                              300x600 Ad Unit (In-View)

                              Collapse

                              300x600 Forums Only

                              Collapse

                              Taboola

                              Collapse

                              Upper 300x250

                              Collapse

                              Lower 970x90

                              Collapse

                              Lower 728x90

                              Collapse

                              Lower 300x50

                              Collapse
                              Working...
                              X