Discharge valves and controls.

[Rossco]

Anyone ever seen any pump discharge controls that want to close during pumping? All pumpers that I've worked with have had stable controls for the most part, and if you forgot to twist lock them in position, they'd stay by themselves at any pressure, or flow. One of our new pumpers has 1 discharge valve that wants to close, and if we are at a high flow, it will slam shut. This handle is of the T handle push/pull style.
The engine will be going back in the fall for a small punch list, and if/when I get any "oh they all do that" bs, it would be good to know more peoples experiences.

[JackTee09]

We had a lot of Macks and one that I remember, Engine 11, would vibrate shut after about 10 minutes. Our Chief Mechanic and his two idiot assistants never wanted to fix the thing...and it couldn't be locked in place.

[Emberxx]

Two suggestions:

Vibration dampeners for your pump panel. This isn't going to completely fix the problem, but it will help slow it down some.

The other suggestion is for you to create a 'lock' of your own. Make a fitting to put on the outside of the gate shaft itself that could be placed up against the pump panel once you've opened it. Use a piece of thick walled tubing with a screw that can be tightened down with an alan wrench.

You'd have to take a second once the lines are pulled and everything is set to place it and screw it tight, but it would keep it from slamming shut on you.

Good luck.

[craigsheets]

You also can make a lock using a piece of PVC pipe with a slot cut longways in it and slip it over the shaft of the handle once you pull it out. Down side to this is that you need several different lenghts for the different possible positions. But, we have an American LaFrance that does this in Pressure Mode and this was our "Fix".

[JackTee09]

Rossco:

How old is the truck? Get the dealer/Manufacturer involved if you can.

[Dave1983]

Ive never seen this with a discharge valve. The tank to pump on our reserve engine will do it. Ive been told that either the tank to pump or recirculate line is too small and when you run the pump up without opening a discharge (just the tank to pump and recirc) its creating a vacume which pulls the valve closed.

You may want to check the plumbing for this valve and make sure everything is correct.

[Rossco]

This engine is brand new, and this is one our concerns to be dealt with when it goes back in the fall. The punch list is not too bad, just a few small issues for the dealer to attend to. This issue is the one safety concern for me. The first time it happened was during our factory training/familiarization drills. We were pumping two 3 inch lines into a ground base deck gun. This was at 250 psi and 750 gpm. The hoses were laying in a half circle arrangement on the ground, and one factory rep was standing inside the circle. The other rep was at the panel, and had both discharge controls locked in position. He then wanted to adjust one dicharge a little, and when he unlocked it, the T handle was yanked out of his hand and slammed shut. The siamese at the gun was clappered, and in theory, it should have closed the clapper, but what happened was the one side still pushing water past the other inlet in the siamese created a venturi affect. The vacuum created was enough to make that lenght of hose shrink in lenght by about 15 feet. Since the rep was standing inside the half moon shaped hose lay, it grabbed him by the back of the legs, and sent him for a wicked ride. Good thing he is a tough old bird, and he didn't get injured. It was scary for a few seconds. We have another new engine with the same pump set up, and it doesn't do this.

Needless to say, this is not good for the pump, and worse yet for a crew that could have been on that line. The valve set up looks very similar to all the rest, and the other engine, so nothing obvious as to why it does this, but we will get to the bottom of it. I was just curious if any of you had run into this before. Thanks for the replies, and ideas.

Tony

[JackTee09]

ROSSCO:

I would be careful making any changes prior to it going back. We all know the answers to what could be done but with a new piece of apparatus caution is urged.

All the best to you and the brothers on this issue.

[Firefig5813]

Have you had more than one instance of this valve closing on its own? One other question, how did you come up with a pump pressure of 250psi for 2 sections of 3" siamesed into a master stream flowing 750 gpm's? By my calculations, your length would have to be near 1200 ft! I only ask because I am a fairly new driver and I am trying to become proficient at my calculations. Hope you have some luck with your truck.

Chris

[doughesson]

Guess someone beat me to this but......

Take a piece of PVC pipe a little larger than the diameter of the pull handle and cut it to the just shorter than the full extension of the pull handle.Then cut a groove down one side so you can slip it around when you want to lock the valve open.
If you want to get fancy,you can paint it red with your department and rig number on it but that's up to you.
We haven't had the problem you described but a neighboring dept did and that's their solution.

[Rossco]

Jacktee, agreed, we won't void our warranty by fingering anything. This is their job to fix. We always work together with our vendors, so any help we can offer by educating ourselves has gone a long way in the past.

Firefig, if left unlocked, the valve will always close by itself while above 150 gpm or so. The engine is in service, and we have plenty of other discharges, so this particular one is not being used untill corrected.

As for the pressure, I was not clear on that statement. The pump pressure was at 250, and both of these discharges were gated back to a lower pressure, to obtain the desired fire flow of 50% of pump capacity. I think you may have been looking for friction loss alone as a factor in our gpm output. I did not do the math that you did, but with a pair of 3 inch outlets, I'd agree it would have been a long lay. ;) Great observation. If you're a new driver, and you're forming a picture like that in your mind, it will definitely lead to improved proficiency.

[Firefig5813]

Thanks, That makes more sence to me. :)

[Dave1983]

The PVC trick may work, but it sounds to me like there is a problem that needs to be take care of the right way not by some homemade prop.

[allineedisu]

It sounds like the pump and may be a Waterous. This is an usual thing for these makes of fire pumps. We always had problems with valves closing with them back in the 1970's.

We now use nothing but Hale, haven't had any problems with them.

[LeuitEFDems]

Rossco, my question to you is, You stated that the 1st time it happened was when the facotry reps were there for "orientation and training" of the apparatus, correct? If this is so, IMHO, the reps should not have "delivered" the truck to you and taken it back with them, or made suitable arrangements to get it back to the factory. They saw the problem 1st hand...instead of having you guys put it on the punch list. I know if we had any malfunction such as that (anything considered "major"...and I say major, becase this problem has the capability of severly injuring someone) during our training phase of the truck, 1) our chief would not accept it, and 2) The reps would take it with them or made arrangements to have it back to the factory in a few days.

[LFD2203]

I would guess that the valve/valve rod is not adjusted properly, causing the valve to be partially open. The only time I've seen a valve pull itself closed is when it has been partially closed with relatively high flows. Just my $0.02.

[lvwrench]

;) Sounds to me like the push pull handle system is missing some metal wafer pieces that provide a friction surface to prevent the return of the handle. This is the area where we have had the problems in the past. The area I refer too is at the panel where the t-handle and shaft come through and the identifier plate is. It should be easy to take apart and check but I agree that if it is under warranty let the maker fix it. The type pump is not the problem and Waterous makes good stuff. The other possible problem is that the valve is not fully opening and allowing pressure build up against the ball causing it to close.

[CAPN22]

Actully this is not uncommon. You didn't state what valves are on the unit. Most new units are running Akron valves. A lot of builders have gone away from a torque lock valve with side controls do to excessive resistance in the valve operation. Thus these are prone to slam shut under high pressure or flows. The t handles must be turned to lock or this is going to happen.

As above if they are not locking there are plates that can be added. also check the screw that hold the plates in, they may be backed off also.

Good luck

[Rossco]

It is a waterous pump, and all waterous valves. The T handles do lock properly, so while their locked, they stay in what ever posistion you set them to. This one valve though, will slam shut when you unlock it, so due to obvious safety issues, we are not using that valve untill its fixed.

leuitefdems, I would love to have sent it back at the time. Long story short, if we had, we would have had no pumper at all. We were replacing a 1974, and a 1968, and right at the time of delivery, our front line pumper went one step closer to the grave. Now we're in better shape, so it came down to doing what you gotta do.

Thanks for the help, I'll advise what we find.

[LeuitEFDems]

leuitefdems, I would love to have sent it back at the time. Long story short, if we had, we would have had no pumper at all. We were replacing a 1974, and a 1968, and right at the time of delivery, our front line pumper went one step closer to the grave. Now we're in better shape, so it came down to doing what you gotta do.

Thanks for the help, I'll advise what we find.
Understandable under those circumstances...I hope you get it fixed soon.