1. #1
    Forum Member

    Join Date
    Sep 2001
    Location
    Xenia, Ohio
    Posts
    10

    Question Class A Pumper Question

    We have a 1987 FMC Pumper with a 1500 GPM Hale pump. We are only able to flow a maximum of 500 GPM through the Deck Gun from tank. We can flow more water with hydrant water, but can only generate 50 PSI PP with a 1 3/4 Tip on the Stang. The pump then seems to cavitate if you increase the throttle, but there is still 1/2 tank water. The tank size is 750 Gallons. We have tightened all intakes and discharges, pump packing has been inspected. We are now told this is normal, and you cannot flow more than 500 gpm from tank. Any input would be helpful.

    Jason Kinley, Lieutenant
    Xenia Fire Division

  2. #2
    Forum Member

    Join Date
    Dec 1998
    Posts
    631

    Default

    What size is your tank to pump line? It may be that the line is not big enough to support more than the 500 GPM. Can you flow 1000 GPM from draft? If so it is probably the size of the tank to pump line or possibly the valve is not opening fully.

  3. #3
    MembersZone Subscriber

    Join Date
    Oct 2001
    Posts
    17

    Post

    With 50 psi and a 1.75" nozzel you are flowing 643 gallons per minute and with your 750 tank you will be empty in 1 minute assuming for tank level indercator is correct or the tubing inside the tank is cleared. Off a hydrant... you should be able to pump what ever that hydrant is capable in producing even if it is 2000 gpm with larger hose connected to the hydrant and to your pumper. Remember to the rated capacity of your pump,in your case 1500gpm, is what it can draft.

  4. #4
    Forum Member

    Join Date
    Jun 1999
    Location
    Cranford, NJ, USA
    Posts
    50

    Default

    First place I would look is your tank to pump piping and see if it
    is properly sized. When you do your pump test you are supposed to be able to flow 80% of your capacity.

  5. #5
    Forum Member

    Join Date
    Sep 2001
    Location
    Xenia, Ohio
    Posts
    10

    Default

    Originally posted by WRENCH
    First place I would look is your tank to pump piping and see if it
    is properly sized. When you do your pump test you are supposed to be able to flow 80% of your capacity.
    Is this true about flowing 80% of your capacity from tank ?? I need to find a specific reference I can use. Thanks for the replies. I suspect that the tank to pump hose may be too small, but the problem seems to be worse that past pump tests.

  6. #6
    Forum Member

    Join Date
    Sep 2000
    Location
    Atlantic,VA
    Posts
    149

    Lightbulb A few ideas

    emstrainer,

    I concur with looking at your tank to pump plumbing. My guess is that you have a single 2 1/2" line with a full flow ball valve for your tank to pump line. This was a common configuration for older pumpers. If so , 550-600 gpm is about the best that you can expect. This is plenty for a 2 1/2" attack line or for a pair of 1 3/4" lines.

    Here are a couple of things to look at:

    Do a pump test to verify pump operation and to rule out pump problems.

    Inspect tank to pump valve for proper operation, It may be only partially opening, and causing a restriction.

    Some trucks have check valves in the tank to pump line, corrosion or debris in the line may keep this check valve from fully opening.

    I'm not sure about the 80% of capacity from the tank. It may be a newer spec. I doubt that a pumper this old will meet it.

    If you have a relief valve on the pump, is it stuck open?

    Good luck.

    Jim

  7. #7
    MembersZone Subscriber
    jsdobson's Avatar
    Join Date
    Aug 2001
    Location
    Anchorage, AK
    Posts
    220

    Wink I found the reference

    emstrainer.

    I'm not sure about the 80% of capacity from the tank. It may be a newer spec. I doubt that a pumper this old will meet it.
    The reference quoted above comes from NFPA 1901 Standard for Automotive Fire Apparatus, 1999 Edition.

    17-3 Tank to Pump Intake Line

    17-3.2* If the water tank has a certified capacity of less than 500 gal. (1900 L), the piping and valve arrangement shall be capable of delivering water to the pump at a minimum rate of 250 gpm
    (950 L/min). If the water tank has a certified capacity of 500 gal (1900 L) or greater, the piping and valve arrangement shall be capable of delivering water to the pump at a minimum rate of 500 gpm (1900 L/min) or the rated capactiy of the pump, whichever is less. This flow shall be sustainable while pumping a minimum of 80 percent of the certified tank capacity with the apparatus on level ground.

    The asterix above means there is more explanation in Appendix A of this standard.

    A-17-3.2 For a pumper, this standard provides for a minimum flow of 500 gpm (1900 L/min) from the water tank. This is to permit the supplying of two 1 1/2 in. (38-mm) or 1 3/4 in. (44-mm) hose lines or one 2 1/2 in. (65-mm) hose line from the tank for an initial attack on the fire.
    For an initial attack fire apparatus, this stand provides form a minimum tank to pump flow of 250 gpm (950 L/min). This permits the supplying of at least two handlines from the tank for an initial attack on the fire.
    Fire departments that want a greater tank to pump rate of flow than these minimums should specify the greater rate of flow.

    So....getting back to the 80 percent thing. As I read it, the tank must be able to flow a minimum of 500 gpm for the first 600 gallons of your 750 gallon booster tank.

    Like the others who have already posted, I think your problem is in the tank to pump valve or corrosion in the piping.

    Best wishes.
    BE SAFE
    Before Everything, Stop And First Evaluate

  8. #8
    Forum Member

    Join Date
    Jan 2000
    Posts
    19

    Default

    Over the years this is one of the things that I have learned from some of our more experienced people when specing out a new truck. If you dont tell them to use oversize lines, and low angle radius plumbing when a truck is built the pump might be capable of moving the water but the internal components of the apparatus wont allow the water to be moved as efficiently as it could be. There are minumum standards that they have to follow, but if a manufacturer can use a 90 instead of 2 45 degree sweeps they usualy will to make things easier in the construction. Have you tried flowing the gun from draft to make sure that the actual plumbing for the gun is large enough to flow capacity?

  9. #9
    Junior Member

    Join Date
    Aug 2002
    Posts
    1

    Default

    You may have a problem in the tank. I have seen 2 mid 80's pumpers with steel tanks that had a problem with a rusted cavitation plate in the tank that dropped down and restricted the flow.

  10. #10
    Forum Member
    CAPN22's Avatar
    Join Date
    Sep 2000
    Location
    Blackfalds, AB, CAN
    Posts
    186

    Default Tank Flow

    1987 most manufactures used a 3" valve as tank supply. This would be Most likely be the case with your unit based on the numbers you have given. And unless you add more supply lines to your pump from the tank it won't get better. Some pumps have Dual 3" feeds into the back. Most a single, regardless. There is only a 3" hole in the back of the pump for tank supply.

    With a 750 g tank I'm not sure why you would put a master stream inplace? if you had a 3000 gallon tank it could see it possibly. But not 750. Booster tanks are generally there to allow an initial attack with hand lines until water supplies can be established. I have always been taught in any operator or command course I have taken that master streams only get deployed after a stable water supply has been established.

  11. #11
    Forum Member

    Join Date
    Jun 1999
    Location
    Cranford, NJ, USA
    Posts
    50

    Default

    Emstrainer , My fault , you need to reference NFPA 1911 pumper service testing. Also reference NFPA 1901 .Asfar back as what I have books for (1989) it was an optional test for acceptance testing. Not having the code in front of me I do believe in the lastest 1911 you are supposed to be doing it as part of your test.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Log in

Click here to log in or register