Pump governors sensing cavitation?

[CCCFire09]

Just had an apparatus salesman (and asst. fire chief of a fire district) tell me that pressure governors will idle the engine for at least 45 seconds when they sense cavitation, and they cannot be reset during this time to restore pressure. I know the loss of supply will cause this, and cavitation is related, but my prior experiences have been contrary. He was also throwing around the name "pump boss" a lot, but he made it sound like this was all governors.

HELP!?

[chiefengineer11]

Just had an apparatus salesman (and asst. fire chief of a fire district) tell me that pressure governors will idle the engine for at least 45 seconds when they sense cavitation, and they cannot be reset during this time to restore pressure. I know the loss of supply will cause this, and cavitation is related, but my prior experiences have been contrary. He was also throwing around the name "pump boss" a lot, but he made it sound like this was all governors.

HELP!?

Go into Fire Research Corp.'s web site and pull up their Pump Boss Product Manual. There is a page on its operation in "Pressure" mode. It doesn't directly say that the unit will detect cavitation, but it does describe what happens under conditions where cavitation would be expected. Read it through carefully and understand what it is saying. You may come to the conclusion that some of the statements that have been made to you are misquotes.

We have one on our Toyne/Spartan (we just upgraded to the PBA 400 that you will see there), and it works as they describe.

[MColley]

It sounds to me like it was a mis quote. I'm not familar with teh "pump boss" but I am familar with the calss 1 govenors and if I'm not mistaken a pressure loss of more than 30 psi will cause the pump to return to idel and flash a warning. Or if it can't regain pressure within 5 seconds it will return to idle and flash a warning. But you can override the warning by taking a corrective action.

I would suspect it essentialy the same thing you need to read the manual on it and understand what to do in that kind of a situation. If you know that what they told you isn't right becuase you've proved it wrong then you probably know more than your sales guy. Even if they are a firefighter they don't neccasarily have to know how to use what they are selling they just have to know how to sell it.

As for a salesman misquoting information "cough" that never happens "cough cough"

[Squirt1262]

We have a FRC governor on our 2009 KME. It senses incoming pressure and displays a "Low Water" message prior to complete loss (i believe it is kicking in about 5 PSI, need to verify with the manual when I get back to the station) the engine goes to idle and you have to start over. This occurs in the pressure setting, in RPM mode it maintains the engine speed. However, we have been able to initiate draft in the pressure mode with no problems.

This is different from our Fire Commander governors on our 200 and 2001 apparatus. Not sure if newer units perform in the same manner as the current FRC govenrors.

Our engineers are still getting use to this feature. We had a drill where we kept the incoming pressure low to simulate a large fire and get them use to how the truck responds. first time it happened, most were a bit confused.

[donethat]

Pressure Gov.

Call me old fashion and resistant to change, but I'll take a hand throttle with a manual pump relief valve and a well trained engineer/operator any day before an electronic Gov.

[chiefengineer11]

Call me old fashion and resistant to change, but I'll take a hand throttle with a manual pump relief valve and a well trained engineer/operator any day before an electronic Gov.

I'm older and in some ways more resistant to change. But we're the ones who will be exiting, to be replaced by people who have no concept of stuff that doesn't run on computers. So the best thing we can do is get used to it and learn to deal with it. The incoming generation of firefighters won't understand the stuff you can actually see working, like a throttle linkage. Reality is, though, that computers and electronics are quite reliable now and are getting better as time goes by.

One of my pet sayings is that each new advance ENABLES us to think and function differently. Each new advance REQUIRES us to think and function differently. I don't think that was ever driven home to me as much as when we went from 2-1/2" and 3" supply line (yes, we did that) to 5".

Mike, which FRC governor to you have on the KME? Also, next Engineers' meeting is Wednesday evening, Oct. 20, at Oreland.

[Squirt1262]

Sam

The InControl 400. Also for us old guys it has a throttle (although it is clockwise versu counter clockwise - traditional throttle) instead of the push buttons.


It works nice, we gave E-12 a workout in Bridgeport a couple of weeks ago - 5 hrs at 1500 GPM at draft (for those outside of SE PA the fire was in an old mill complex during 95+ degree weather).

Will put the Engineer's meeting on the calendar, had a conflict with a Township Public Safety committee for the last meeting

Mike

[chiefengineer11]

Sam

The InControl 400. Also for us old guys it has a throttle (although it is clockwise versu counter clockwise - traditional throttle) instead of the push buttons.


It works nice, we gave E-12 a workout in Bridgeport a couple of weeks ago - 5 hrs at 1500 GPM at draft (for those outside of SE PA the fire was in an old mill complex during 95+ degree weather).

Will put the Engineer's meeting on the calendar, had a conflict with a Township Public Safety committee for the last meeting

Mike

You would have the newer version of the InControl, then. We might have gone with that but a J-1939 version wasn't available then. At the time, FRC said they weren't going to develop one, either, so we went with the Pump Boss. It works well and we're happy with it, especially after we upgraded to the PBA 400. It will be interesting to compare the two after a few years. Thanks.

[FWDbuff]

Call me old fashion and resistant to change, but I'll take a hand throttle with a manual pump relief valve and a well trained engineer/operator any day before an electronic Gov.

You are old fashioned and resistant to change.

[Squirt1262]

Sam

We looked at both as well as Class I. The biggerst difference between the Pump boss and InControl appears to be having the digital master gauges. This allows you to drop the main gauges from the panel. We kept them on ours, Upper Black Eddy has only the govenor displays on their tanker (2008? 2009 KME Tanker) The layout also fit better into the pump panel design

Having both on the panel confuses the new engineers since they are not identical readings. we tell them to focus on one set or the other instead of both. The compund reading appears to be low on the intake presure, however it is great when drafting knowing where you stand on the vacuuum side. On the Pressure guage, the reading is within 5 PSI through the range of the normal pressures we use

Has anyone tried to resolve the discrpancy between the two readouts?

[chiefengineer11]

Sam

We looked at both as well as Class I. The biggerst difference between the Pump boss and InControl appears to be having the digital master gauges. This allows you to drop the main gauges from the panel. We kept them on ours, Upper Black Eddy has only the govenor displays on their tanker (2008? 2009 KME Tanker) The layout also fit better into the pump panel design

Having both on the panel confuses the new engineers since they are not identical readings. we tell them to focus on one set or the other instead of both. The compund reading appears to be low on the intake presure, however it is great when drafting knowing where you stand on the vacuuum side. On the Pressure guage, the reading is within 5 PSI through the range of the normal pressures we use

Has anyone tried to resolve the discrpancy between the two readouts?

Good point, Mike. I don't know if anyone has. Good question for the folks on Lorraine Av. You may remember that they started or participated in quite a brouhaha with the people in Wisconsin over a different point that affected the accuracy of gauges.

Bring the question to Engineers' meeting. Panel gauges aren't known for super accuracy. I think NFPA allows +/- 5%. So on any pump panel you may see (and we do) varying readings. Example: Master gauge reads 100. Leave a discharge capped and open its valve. It may read anywhere from 95 to 105. And if the gauges were never zeroed from the start, the reading discrepancy may be even greater. And I'm sure they can vary throughout their lifetimes.

It's one of the reasons that you hook up lab gauges to do pump tests.

[Capt387]

Call me old fashion and resistant to change, but I'll take a hand throttle with a manual pump relief valve and a well trained engineer/operator any day before an electronic Gov.

Agree there! Had a gov system fail with two men in a garage fire that as they arrived near the seat and needed to flow water. Just luckily (this isnt a norm) I had a second engine near the intersection and we pulled a line off it.

[chiefengineer11]

Agree there! Had a gov system fail with two men in a garage fire that as they arrived near the seat and needed to flow water. Just luckily (this isnt a norm) I had a second engine near the intersection and we pulled a line off it.

No matter what kind of throttle control you have now, it's electronic, and it feeds into a computer. Look behind the pump panel, there's no cable, just wires feeding the engine's computer. Whether you try to keep up with water flow demands by turning it manually, or whether you let the sensor make the changes instantly for you, the same thing is happening. The EPA took cables and linkages away from us during the early '90s.

[Squirt1262]

Correction

My earlier post regarding the pump cavitation noted that the governor will go to idle at about 5 PSI on the Incoming pressure.

After re-reading the operations manual for the FRC InControl 400 the actions by the governor are based on the discharge pressure not the incoming pressure. The governor will sense a sudden drop in discharge pressure (within preprogramed parameters) or a drop below 15PSI DP and respond with an increase in RPM. If the pressure does not increase within a specific time frame the governor will change to RPM limit mode or to idle depending on the condition. The governor is programed for "Running away from Water", Low Water Cycle, and No Supply Water".

The key is that the unit is monitoring discharge pressure not incoming pressure for all of these functions even though it may look diferently when you are at the pump panel.

Sorry if I confused anyone with my earlier post. Goes to show that the manuals have a purpose other than collecting dust on the bookshelf. The good news is that I now have some material for the next Engineers Class at the station. The scenarios should be easy to simulate. It also explains why the governor will not sense low water while at draft.

Is this the same process used by Class 1?

Mike

[Johngagemn]

My earlier post regarding the pump cavitation noted that the governor will go to idle at about 5 PSI on the Incoming pressure.

After re-reading the operations manual for the FRC InControl 400 the actions by the governor are based on the discharge pressure not the incoming pressure. The governor will sense a sudden drop in discharge pressure (within preprogramed parameters) or a drop below 15PSI DP and respond with an increase in RPM. If the pressure does not increase within a specific time frame the governor will change to RPM limit mode or to idle depending on the condition. The governor is programed for "Running away from Water", Low Water Cycle, and No Supply Water".

The key is that the unit is monitoring discharge pressure not incoming pressure for all of these functions even though it may look diferently when you are at the pump panel.

Sorry if I confused anyone with my earlier post. Goes to show that the manuals have a purpose other than collecting dust on the bookshelf. The good news is that I now have some material for the next Engineers Class at the station. The scenarios should be easy to simulate. It also explains why the governor will not sense low water while at draft.

Is this the same process used by Class 1?

Mike

This is a safety system that should be present in any new electronic pressure governor. The idea is that you don't want the pump catching prime again with the engine at max speed, otherwise the crew on a handline is going to be in for a wild and dangerous ride. As someone who has taken that ride on a pumper with an older electronic governor, I like the cavitation protection built into the new ones.