We have had a problem with our Scott 4.5 airpacks going into low pressure alarm at about 50% capacity instead of the 25% it should be. A valve in the pressure reducer becomes iced up during regular use and causes the alarm malfunction. We have checked the moisture content and dew point of our air, and it all meets specs. If anyone else has had this problem, please let me know. Thanks.
The problem first started when we first started training with the new packs last August, and it continues still. Our department is in Eastern NY State, and it can get cold. However, the problem occurs even during interior suppression evolutions at live burns and during structure fires.
[This message has been edited by ChiefAJM (edited 03-29-2001).]
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Thread: Scott problem
03-27-2001, 03:31 PM #1ChiefAJMFirehouse.com Guest
03-28-2001, 09:41 AM #2FFTrainerFirehouse.com Guest
What time of year is this happening? Has it only been these last few winter months?
We had and sometimes still have a problem with freezing of a few SCBA from time to time during the winter months. It had nothing to do with moisture content of your cylinder air or with pack malfunction. It was simply condensation that formed from the FF breathing into the MMR and when he stepped out of the structure into the cold outside air, it would begin to freeze and produce various strange behaviors.
03-29-2001, 12:55 PM #3res7cueFirehouse.com Guest
We have seen this a few times, it usually occurs when the temp is extremely cold and the BA is being used outside for extended periods.
03-29-2001, 02:57 PM #4d308Firehouse.com Guest
We just ordered 4 complete set of scott 4.5. Is this a problem that occurs reguraly and what is the temp that it starts to occur at also is there a quick fix if we experience the same problem
03-29-2001, 08:22 PM #5RichardlFirehouse.com Guest
Have you contacted your local Scott service center? Give them a detailed description of the problem and have them conduct a flowtest on the affected units. It sounds like a problem inside the reducer assembly. If someone qualified can take a look inside, it might help to identify the cause.
The 4.5 has a small, inset button on the reducer for testing the swtich from the primary to the secondary reducer stage. Do the affected units switch over normally? (Just curious). (While using the unit, have someone push in the button with a small punch or allen key. The vibralert should be activated and should stop within a few breaths of the button being released.
03-29-2001, 10:32 PM #6BFD251Firehouse.com Guest
we had a problem one time with moisture in our pressure reducer the scott service repair tech. that was there asked if maybe the frames got submerged in water when they were cleaned, well some of them were. so he seemed to think thats how moisture got into the pressure reducer. now no airpaks are submerged in the cleaning water and we haven't had any problems....
03-30-2001, 01:12 AM #7sohardyFirehouse.com Guest
This may not solve your problem, but something to check. I had this same problem on a fire this past January(20-25 degrees), another FF heard me tell the safety officer and he told me that he had the same problem on a previous fire, and to check that the bottle valve was fully open, mine was not, I opened it all the way and the problem stopped immediately. We couldn't believe it was that simple, but it worked.
07-16-2006, 10:26 PM #8
the 4.5 is an awesome pack. I have seen the low pressure alarm go off during freeze up...my question is this. Does it truly "Go off" or does the regulator viberate off and on? at sub-zero temps i have seen the regulator viberate off and on, for very short periods.
Due to the extreme cold we use the one hour bottles, mostly because the regulator freezes to the mask and the coupling freezes to the pack making changing bottles difficult.
One of the things you might want to look at is a cold weather mask. It has only one exhalation valve and a rubber piece in the regulator that prevents moisture from entering the working parts of the regulator.
Contact Scott and see what they advise. they have always been a pleasure to work with.
Incidently i have used this pack with the above mentioned mask at 50 below zero and experienced no problems.
Last edited by pedalinmedic; 07-16-2006 at 10:29 PM.
07-17-2006, 10:56 AM #9
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I doubt you'll get an answer considering its 5 years later and they're not registered.
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