Pressure Governor Help

[DelSol]

Hello. I'm in the process of learning how to be a MPO and I was hoping to get some help with something I'm confused on and that some of my fellow members are not helping but making me more confused.

I'm looking for an explanation on how pressure governor's work and more specifically when you would use the pressure mode vs. the rpm mode.

Any and all help is greatly appreciated.

Thanks you and be safe.

[LFD2203]

Try to think of a governor as a device that maintains either the engine speed or pressure, depending on if you are in the rpm or pressure mode.

In the rpm mode, the engine speed is kept at a set level, regardless of the load on the engine. So, if you are pumping water with multiple hoselines off, the pressure on each line will fluctuate as the nozzles are opened and closed. 1 nozzle open, pressure would be higher than when 2 nozzles open, etc........

In the pressure mode, the engine speed will fluctuate to keep the pump pressure at it's setting. As more nozzles open, or if you start with tank water and go to a hydrant or supply from another pump, the engine speed will change. If all nozzles are closed, the engine speed should drop, maybe to idle. As lines open, the engine speed should increase to develope and maintain the pressure setting. If you have multiple lines off and they are being opened and closed alot, the engine speed will constantly be changing.

Hope that helps........

[bobsnyder]

I don't know if this will help or not, but...

I generally pump in "pressure" mode when the engine has handlines deployed. This makes it much easier to maintain specific discharge pressure(s) on the lines, regardless of fluctuations in incoming supply pressure or flow, or in water usage by the hose teams. I also generally work in pressure mode for any supply operations where the destination is another pumper, although that's not a hard and fast rule with me.

I prefer to pump in "RPM" mode when operating direct from a static source or when filling tankers from any source. In the former case, it's really just personal preference. But when filling tankers through direct fills, there is no back pressure at the destination and generally little back pressure generated by friction (unless the fill site is at the end of a long lay or the line isn't LDH for some reason). In that case, there's no pressure for the governor to maintain ("pumping into infinity" one of our older guys calls it), so you need to be in RPM mode.

[ChiefDog]

Hello. I'm in the process of learning how to be a MPO and I was hoping to get some help with something I'm confused on and that some of my fellow members are not helping but making me more confused.

I'm looking for an explanation on how pressure governor's work and more specifically when you would use the pressure mode vs. the rpm mode.

Any and all help is greatly appreciated.

Thanks you and be safe.

I think you got your answer here

http://forums.firehouse.com/showthread.php?t=88248

[Catch22]

It might also help you to dig out the operator's manual for the governor on your truck. If they aren't around anymore, go to the manfacturer's website and see if you can't download one.

While the guys all have good info posted, it's never a bad idea to see what the manufacturer has to say. You'll learn a little more on the ins and outs of your specific governor that way.

[ChiefDog]

It might also help you to dig out the operator's manual for the governor on your truck. If they aren't around anymore, go to the manfacturer's website and see if you can't download one.

While the guys all have good info posted, it's never a bad idea to see what the manufacturer has to say. You'll learn a little more on the ins and outs of your specific governor that way.

So you mean R. T. F. M.

[Catch22]

So you mean R. T. F. M.

OK, it's been a long day, RTFM means...?

[fire0099881]

OK, it's been a long day, RTFM means...?

if my memory is serving me correctly it means Read the F'in Manual!!!!! something most people don't do!!!

[ChiefDog]

if my memory is serving me correctly it means Read the F'in Manual!!!!! something most people don't do!!!

Yup... thats what it means. Not trying to be a wise-guy but the fact remains that you go to the manufacturer and they probably are the "expert" on the item they designed and made. It is kind of hard to not follow the instructions and complain it doesn't work right. Their first answer will be but on page 8 paragraph 3 it states: " You shall do...."

[Catch22]

I should have known that! Like I say, it'd been a long day. However, it rings true, too many times have I seen guys that have no clue what the manfacturer has to say about equipment/apparatus.