We had this occur once this summer, and we are looking for a way to help prevent it.
While operating a hoselay at a wildland fire the 2 FFs were off the brush truck about 500 feet away from the unit. They hit the end of their hoselay and started franticaly punching in handline to finish off the last 50 yards of fire which in accesable by brush truck and beyond the reach of their hoselay.
They didnt have anybody left to watch the brush truck which kept on pumping furiously with nowhere for the water to go ecept around and around the pump housing.
This of course heated up and recked the seals in the pump.
This is a relatively infrequent problem, but one we are looking to address none the less.
Its not like the FFs dont know it can happen. We have everybody trained on pump operations and we have shown them how a pump heats up without water flowing with our TIC. Sometimes though you are not able to crack the bypass valve because you are pre occupied.
What I would like to do is put a temp gauge on it that lights up a warning light (thinking 1 inch LED cube, 4 LEDs and cheap) in the cab on on top of the brush truck. That way the guys can run over and bypass some water when the light comes on. Just a reminder.
The problem with our brush trucks is that they do not auto bypass. This is so that you can get the max pressure for long hoselays and to keep foam out of the tank. Some people drill a tiny hole in the bypass valve so a tiny amount of water always keeps moving, but this lets foam in the tank and robs some top end PSI and may make priming for drafting and such more difficult. The spring loaded presure sensative bypass valves have proven in the past to cause more trouble then the solve.
So, does anybody have a suggestion on a temp gauge? Are there any that just stick on, we do NOT want to drill and tap a hole in the pump houseing. There are no holes that we can use already in there either. We want someting that just sticks to the outside or that can be mounted with a small braket or something.
Also, at what temp do you think things get critical? Can a pump handle the heat up until boiling point? That would mean we could use automotive temp sensors.
Here is bacily what all of our brush trucks look like, with a few variations in make and model of pump and engine.
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Thread: Small pump Burnout!
07-29-2004, 01:23 PM #1
Small pump Burnout!-Brotherhood: I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve.
-Mistakes: It could be that the purpose of you life is to serve as a warning to others.
-Adversity: That which does not kill me postpones the inevitable.
-Despair: Its always darkest before it goes Pitch Black.
07-29-2004, 03:08 PM #2
For "workable" pump housing temp. I would contact the mfg. directly and in writing.
As for a temp. transducer - don't know of any "stick on" types but I understand not wanting to drill into the pump housing. So why not tap into the discharge plumbing directly adjacent to the pump housing?
1) You really want to measure the temp of the water as it will heat faster / hotter than the housing.
2) The water in that area will heat up nearly as fast as in the pump housing itself.
My only other suggestion is to simply keep the by-pass open as a rule and then only shut it when you are pumping long lays or using foam.Take Care - Stay Safe - God Bless
07-29-2004, 04:41 PM #3
Does your pump have outlets for attaching delivery hose to and a separate valve for tank filling when its empty?
If it does, just cut down an old length of LDH (we use a 70mm diameter hose)about 6/8ft long, depending on how far apart the valves are, and attach the appropriate couplings.
When you are moving the vehicle or running hose with the pump running when not moving water, connect the length to the delivery hose outlet and tank valve and open them both up. This means that the pump will move water round the system, but as it is pumping it through the water tank, it will not cause the pump to overheat. I don't know what capacity the water tank on your truck is, but even if its only a couple of hundred gallons, that will take some time to heat up.
This method is used by most UK fire services, and is a good way not only to prevent pump damage, but prevents run off from open deliveries onto the ground, saving water, an also preventing the vehicle from becoming bogged down on open ground by water collecting under it.
Hope this helps.United Kingdom branch, IACOJ.
07-29-2004, 11:08 PM #4
- Join Date
- Dec 1998
We use a 1/4 turn valve on a 1/2" line from the pump discharge side back to the tank. This valve is normally left about 1/2 open to prevent pump overheating. A 1/4" stream from the discharge should be ample to keep wildland pumps cool. It has little effect on the pressure to your attack lines but can be closed if needed.
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