1. #26
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    Default

    Brian - Thanks very much for your clear explanation of the whats and whys of how your pressure governors work. My only comment refers back to one I made in an earlier post; that is, since our primers are electric motor driven, they operate completely independently of the vehicle engine. I get a prime before selecting anything on the pressure governor. Once I have my prime, I select "Pressure (usually) and ramp up to my desired discharge pressure.

    Understand, of course, that I'm using a Barber Colman unit on a mechanically controlled Detroit 6V. It doesn't default to anything. You have to select either "Pressure" or "RPM" to get anything out of it. Otherwise it does nothing at all. Also, by its design, if you change modes it goes back to idle and you have to ramp up again. I understand that newer units such as FRCs do not do that.

    From going through the Interactive Training Module for the "Pump Boss" on the FRC web site, I gather that even though it defaults to "Pressure" mode when you engage the pump, you won't immediately get a pump runaway condition. So for that reason, I wonder why I wouldn't want to just accept the default setting, establish my prime, then ramp up from there.

    Also, we deal with exceptionally high hydrant pressures. When switching from tank supply to hydrant supply, having the governor in "Pressure" mode allows it to drop the engine RPM to more closely represent what's needed to maintain the desired discharge pressure. I'm assuming and hoping that the FRC unit, when we receive it, will do the same thing.

    Any comments or corrections?

    Stay safe out there, everyone goes home!

  2. #27
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    Default operating in Pressure Mode

    Chiefengineer11,
    The PumpBoss has "Running Away From Water" protection that will not allow the engine rpm to increase more than 300 rpm with out an increase in the discharge pressure. This will take care of most of the possible problems of astablishing a prime from draft or changing your water source while in "Pressure Mode". The most important thing to remember is to bleed all of the air out of the supply line before opening the intake valve to the pump.

  3. #28
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    Default Pump Boss

    Thanks for the additional info, Fixer. I'm understanding that when I go from Road to Pump, the unit will default to Pressure and Idle. Am I also right in assuming that if no additional throttle is called for, the engine will remain at idle until the system sees a request for more? If so, I don't see a problem. I should be able to get a prime, then begin ramping up to the desired operating pressure.

    Stay safe out there, everyone goes home!

  4. #29
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    Quote Originally Posted by Firefixer View Post
    When switching the water supply source from tank to hydrant, draft to hydrant, or draft to relay, water flow through the pump can become turbulent and the positive pressure from these sources may generate a sudden pressure surge. It is recommended that the governor be set in “RPM” mode before changing the water supply source. After you have completed changing your water source, switch back to “PRESSURE” mode of operation.
    I'm a little confused. You are saying to set the governor to RPM mode, thereby eliminating the pressure regulating effect of the device at a transition point that requires pressure control to keep from damaging equipment and knocking firefighters off their feet. Can you explain more? NFPA has allowed pressure governors in place of relief valves. By setting to RPM mode and having no relief valve, you have NO discharge relief protection. We run our handlines at 110 and 120 PSI usually. When the 100 PSI from a hydrant hits the pump thats already spinning 110 PSI to the handline, thats going to cause a discharge pressure of around 200 PSI. Thats dangerous unless theres regulation by the pressure control device. We train all of our operators to leave it in pressure mode when making that transition so that the governor can kick the engine speed down once more pressure is detected from the hydrant pressure.

  5. #30
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    Default operating in Pressure Mode

    chiefengineer,
    You are correct, when the governor is engaged it will always default to pressure mode. The engine RPM will remain at idle, the governor does not become active until a command is supplied by the operator by pressing the preset button or turning the control knob on the PumpBoss. If the ProS or Incontrol are used you have to press the Preset, Increase or Decrease button.

    MG3610,
    The PROS and the INCONTROL pressure governors have two stages of cavitation protection, the "No Water" and "Low Water" modes. Neither of these would prevent the pressure governor from increasing the engine RPM if air is introduced into the pump while switching water supplies. This can happen when you do not bleed the air from the supply line prior to opening the intake valve. The air in the pump will cause the pressure governor to increase the engine RPM while it attempts to maintain the pressure selected by the operator. When the air makes its way out of the pump and into the discharge line the water from the intake fills the pump which is know spinning very fast. This could cause a pressure spike.
    The PUMPBOSS governor has a third stage of protection called “Running Away From Water”, this will prevent the engine RPM from increasing more than 300 RPM with out an increase in the discharge pressure.

  6. #31
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    Quote Originally Posted by Firefixer View Post
    chiefengineer,
    You are correct, when the governor is engaged it will always default to pressure mode. The engine RPM will remain at idle, the governor does not become active until a command is supplied by the operator by pressing the preset button or turning the control knob on the PumpBoss. If the ProS or Incontrol are used you have to press the Preset, Increase or Decrease button.

    MG3610,
    The PROS and the INCONTROL pressure governors have two stages of cavitation protection, the "No Water" and "Low Water" modes. Neither of these would prevent the pressure governor from increasing the engine RPM if air is introduced into the pump while switching water supplies. This can happen when you do not bleed the air from the supply line prior to opening the intake valve. The air in the pump will cause the pressure governor to increase the engine RPM while it attempts to maintain the pressure selected by the operator. When the air makes its way out of the pump and into the discharge line the water from the intake fills the pump which is know spinning very fast. This could cause a pressure spike.
    The PUMPBOSS governor has a third stage of protection called “Running Away From Water”, this will prevent the engine RPM from increasing more than 300 RPM with out an increase in the discharge pressure.
    OK. So if proper etiquette and tactics are followed and the air is bled (as it very well should be) then the governor staying in pressure mode is the safest way to protect the discharges from the spike of the incoming water pressure. You kind of only half answered my question.

  7. #32
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    Cool Governor Woes

    This thread has certainly highlighted a problem - pump governors are complicated, and require a considerable amount of training - More training than any other pump component or accessory.

    I remember when I first learned about pressure relief valves. It took about 15 minutes to become comfortable with it.

    When a pressure relief valve fails on scene, we lose pressure protection and the engineer has to be more vigilant. When a governor fails (or reacts wildly to the presence of a small amount of air) we could potentially lose discharge pressure entirely. Which situation are you more "comfortable" with?

    And I will continue to change from tank water to hydrant water in PSI mode.

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    Quote Originally Posted by clifton36 View Post
    This thread has certainly highlighted a problem - pump governors are complicated, and require a considerable amount of training - More training than any other pump component or accessory.

    I remember when I first learned about pressure relief valves. It took about 15 minutes to become comfortable with it.

    When a pressure relief valve fails on scene, we lose pressure protection and the engineer has to be more vigilant. When a governor fails (or reacts wildly to the presence of a small amount of air) we could potentially lose discharge pressure entirely. Which situation are you more "comfortable" with?

    And I will continue to change from tank water to hydrant water in PSI mode.
    Clifton,

    I agree with you on several of your points!

    I would rather have a pressure governor over a relief valve any day. Why? Because the relief valve is probably the most ignored piece of equipment on a pump. Most operators of pumps (Lever Puller/Button Pusher not true pump operators) have no clue what a Relief valve is or what it does.

    Training on a Governor is a must! It also makes sure that the person operating the pump has pressure protection on the hand lines that most likely would not be there if the pump was equipped with a relief valve. Most departments do not train there drivers/operators in the proper use of the Governor.

    As for switching from tank water to hydrant water could not agree with you more, PSI mode is the way to go.

  9. #34
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    Chief:

    Within my FD I am a huge proponent of the pressure governor. Just the fact that it can maintain the set pressure (corrects a pressure drop as well as a spike) makes it better than a relief valve. You also don't have to reset it after every change in flow. It appears that our problems (other than training 300 engineers) are related to the Class 1/CAT combo, and FRC and Detroit deserve a hard look.

    The recommendation by FRC and Class 1 of changing water supply sources in RPM mode points out a major flaw in the syetm - the sensitivity to air. They need to be more straightforward with this issue (and maybe they are in some cases, but we had to figure this out ourselves).

    And you are correct about the relief valve being ignored. But the primary reason they are ignored in my department is the fact that 75% of them don't work. They are Hale TPM valves, and the high sediment in our water supply requires rebuilds every 6 months. Our shop can't keep up, which is the primary reason for the switch to governors. We purchased governor equipped engines in 1991 (Waterous pumps with Detroit governors) and in 1994 (Godiva pumps with a no-name crap governor). In between we always buy relief valve equipped pumps, so we are constantly re-training. If we stick with ONE type of pressure relief system, buy one that works, train the engineers, and maintain the system we wouldn't have a problem now.

    I have gained some good information from this thread. Thanks for all the replies to my posts.

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    Is it just me or does it now seem like Class 1 and FRC have their heads a little buried somewhere dark? One of the main points of a pressure governor (especially if being used in place of a relief valve) is to regulate pressure. Both have advocated not using the pressure regulating feature at crucial times of need (aka switch to hydrant from tank water).

    Our 1994 KME's have the Detroit 8V92TA engine with a class 1/detroit governor. The pump intakes have air controlled butterfly valves. When you flip that switch, lookout.....here comes the surge. Without the governor in PSI mode, you would launch the nozzleman!! We have trained quite a bit on them and always had success with the PSI mode controllign that huge surge from the switchover. Interestingly enough, these 2 rigs also both have Hale TPM relief valves. The major issue here is that in PSI mode the governor tries to fight the relief valve and race the engine when it opens. Works fine in RPM mode though.

    I'm starting to think we would be beter off going back to vernier throttles and discharge relief valves.

  11. #36
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    First of all, air actuated intake valves do not meet the NFPA requirement for minimum of 3 seconds from full closed to full opened. Not sure why you have these valves on your apparatus, but sounds like they should have been electric actuated in this application.

    Don't give up on the governors, they really do work better than throttle/relief valves. The usual reason for these statements is lack of information, or lack of willingness to embrace new technonlgy. Its not as complicated as some try to make it. Do your homework, and base your position on FACT, not EMOTION!

  12. #37
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    Default Just the FACTS

    Quote Originally Posted by HFD147 View Post
    First of all, air actuated intake valves do not meet the NFPA requirement for minimum of 3 seconds from full closed to full opened. Not sure why you have these valves on your apparatus, but sounds like they should have been electric actuated in this application.

    Don't give up on the governors, they really do work better than throttle/relief valves. The usual reason for these statements is lack of information, or lack of willingness to embrace new technonlgy. Its not as complicated as some try to make it. Do your homework, and base your position on FACT, not EMOTION!
    You are incorrect. NFPA allows air actuated valves for intakes. Current technology allows for adjustment of opening speed. In 1994, when these standards were different, alof of todays requirements werent applicable. We also have 4 3" discharges with regular ball valves and swing handles.

    16.6.4 of 1901 (2003) says the intake valve must be slow open/slow close referenced in 3.3.152 as any valve that opens from the fully closed to fully open position in no less than 3 seconds and vice aversa. I assume that wasnt required in 1994, as the style air valves we have are common on many rigs I have seen.

    Akron's air valves are NFPA compliant. http://www.akronbrass.com/pages/akro...actuators.html

    I will agree that the choice to select air valves was poor at best. Live and learn.

    I see what you are saying about not understanding somethign and givign up on it, but thats not the case here with me. I am frustrated because 2 manufacturers state to use the device in a manner which makes it effectively useless at a crucial transition point. Makes alot of sense huh???

  13. #38
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    OK, you're right about the standards in 1994 vs. today. My air actuated intake valve comment was based on our experience, but is due to excessive hydrant pressure. If you "detune" the air actuator to compensate for speed, you lose the torque required to allow the valve to open under pressure. At any rate, in my opinipon the only intake valve suitable for air actuators is the tank-to-pump. The rest should be electric or manual handle or gear actuated handwheel control. The air valves are too hard to get to operate the right way for every application.

    As far as the pressure governor issues between PSI and RPM, we just haven't experienced the issues some others have in this thread. Lucky? Hope so. But ours have been working fine for 10 years now, and we wouldn't hesitate to buy one again next time.

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