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Oxygen Pressure Alarm


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Ok, so I just took receipt of a 2000 F350 Super duty 4x4 ambulance.

The way this box is designed, places the main O2 cylinder under the bench seat which is a first for me. This means I now have to turn on the main O2 when I load a patient and remember to shut it off when we offload.

Anyways, here is the problem. The O2 has a low pressure alarm that emits this annoying high piercing alarm when ever the main O2 is shut off and the power is turned on to the module. You have to jump in back and hit the silence button and then it is fine, however it is not practical for us to do this every time before responding to a call. We must have the power on while responding or the lights and sirens do not function plus the AC will not be cooling the back.

My other option is to leave the main O2 on all the time thereby eliminating the trigger for the alarm, however we have discovered when we leave the main O2 turned on that there is a small leak and we do not wish to deplete our O2 levels as getting tanks refilled is not the easiest task at my current location.

Does anyone have any suggestions on how to over ride this alarm or keep it from triggering?

Is anyone familiar with this type of setup?

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All of our Horton rigs had this. Every time I start our 98 Horton, put it in drive, that damn alarm goes off. "Oxygen Warning" the console reads. Any oxygen in the line at all, will set it off. Now on ours, you can cancel it out by pressing one of the two buttons right below the data screen. However, the best way to override it, is to bleed the system completely after you shut off the oxygen. To do this, kill the tank. Shut the rig off, open the manual bypass valve, and run either a demand or a flow meter until opening and closing the bypass doesn't cause the ball (if you have conventional flow meters) to rise and fall.

We have a demand valve hooked to the wall over the bench seat, so that's how I bleed the system off. We had a Ford Superior ambulance, similar to a Baltimore Box (yeah - the same people who made the Cadillac Superior) for a few months in 2001. It was set up to run off of three "E" cylinders.. and that just won't work with our time on the road. So, we hooked up it's piped system, an under the bench model.

Didn't have an alarm, hell, it's seats were fold down and it had shock lamps (blue light); lucky it had oxygen at all. But I recall doing a few transports.. Getting the patient all ready, slamming my head on the too low to be legal ceiling, and cursing.. Stop.. Open the back door, get out, peer into the dark hole, turn on the oxygen tank, climb back in, hit head on hanging stretcher hardware, curse, slam door shut, it bounces back open, remember that it's a D ring handle, close it again... Okay, go.. Anyhoo.

I can tell you how we accidentally disabled the oxygen pressure sensor in our 09 Marque.. Rip the wires out of the regulator. There should, or may be wires hooked directly to the main tank regulator. They go to the sensor and alarm. If they aren't attached, it won't work. As to how they became detached. :whistle:

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No worries mate!

Since I am the boss, there is no need to "accidentally" do anything.

I got brave, removed the panel, traced the wires and actually found a plug adapter, so that is what I did. A simple unplugging as opposed to cutting...but I was prepared either way. :)

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No worries mate!

I got brave, removed the panel, traced the wires and actually found a plug adapter, so that is what I did. A simple unplugging as opposed to cutting...but I was prepared either way. :)

Brave or (fill in the blank) cut wires may lead to way more issues with ground fault interrupter :o

The way this box is designed, places the main O2 cylinder under the bench seat which is a first for me. This means I now have to turn on the main O2 when I load a patient and remember to shut it off when we offload.

Under your ass ? ... one of my trucks is external access to MAINS ... quit your whining pretty boy :spell:

Anyways, here is the problem. The O2 has a low pressure alarm that emits this annoying high piercing alarm when ever the main O2 is shut off and the power is turned on to the module. You have to jump in back and hit the silence button and then it is fine, however it is not practical for us to do this every time before responding to a call. We must have the power on while responding or the lights and sirens do not function plus the AC will not be cooling the back.

Could do a procedure change open side door and turn ON O2 MAIN before ignition ? Do you have shore line charger system and keep power ON to panel, could save you from using all your D and E tanks in the event that occurs.

Ah the design for dummy's frankly, as that is stupid design in itself It SHOULD be Low Pressure alarm even with no key in the ignition or power ON ! as that way one would hear the alarm before a call out, sheesh engineers have no idea sometimes, The way these things are designed now it is presumed that MAIN 02 ia always ON, flow meters OFF as in a metro service but no consideration for any OTHER applications, I don't think you have a spare gut wagon to dispatch do you ? :mobile:

Ok safety/medic boss man ... Your defeating an alarm that is telling you something, Now if I am picking up what your laying down that is ... I suspect you either do have a LEAK somewhere, OR your bleeding off internal O2 internal circuitry pressure, engineers design theory there is always pressure in the system ( I think it was made for Fire Based Medics) .... I sense incoming LOL.

Options to consider:

1- You have a leak.

2- Your bleeding off pressure every trip, So DONT leave the syestm pressurized, so what if you loose 200 psi a month.

LEAK TEST:

Turn off the Main and assure that the "ALL" O2 outlets are either turned (or removed) off then observe the pressure over 24 hours a dropping pressure/ alarm indicates a leak somewhere, No drop in pressure then a good system.

If it Alarms:

a) Flow meter leak (eliminate from circuit) try pressure test again.

B) You may have an factory internal circuit leak.

c) Wall outlet leak.

SO if you get an alarm you have a leak somewhere, a spray bottle with a touch of detergent will help you find it (do I need to say turn the power off and don't spray the electric looking stuff) :rolleyes:

ELECTRONIC issue.

It could be your Main regulator needs a Bio med tweak or even put an in line gauge to check to see if its a regulator needs pressure adjustment and set higher than the electronic pressure sensor or if its the electric pressure sensor (is that adjustable?) or is it just a stupid little plastic box that you disconnected electrical leads or the alarm box AND does if function to alarm for other reasons too ? just saying.

A jury rigged Burdon Gauge with "items" borrowed from car pool or aircraft maintenance, always an option if you want to do some pressure testing.

If you DO NOT want to work with the dummy system, although if some clown leaves a flow meter ON and the MAIN ... YOUR HOOPED AGAIN and have to change out a MAIN, it kinda delays a response too. :thumbsdown: but seeing as your the big safety/boss/hose monkey man ... turn off the idiot alarm and hope and trust everyone on the truck does the same and turn off the MAIN every call ... yea ok cause that has never happened to me, right then ( a bit more involved when M tank is fixed on a King Air) and back to more incident reports.

Just a suggestion do daily AM 02 checks, SOP (recorded) if you decide to defeat idiot alarms.

cheers

Edited by tniuqs
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Oh Squinters....what to say to you man.

First, let me clarify the already resolved issue.

1. Truck module power on, main O2 off, regulator off = ALARM

2. Truck module power on, main O2 on, regulator off = ALARM

3. Truck module power on, main O2 on, regulator on = ALARM

4. Truck module power off, No O2, No Lights, no nothing

Daily checks always include checking the pressure gauge attached to the regulator, so no issues there.

Yes, I trust my crew to always turn it off as we are much more conscientious of these things due to our location and inability to rapidly replace or refill anything. Our failures will cause harm to others, so we can not allow that.

What say you now Canuckster?

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2. Truck module power on, main O2 on, regulator off = ALARM

Yea I reread my post, note to self no more beer in the morning, te he. Point being if there was a legal liability issue, defeating an alarm could put one in a bad light, yup highly unlikely in your case this would become an issue elsewhere as for trust with partners, dude anyone can make an error, I have forgotten to shut off Mains and that was an issue putting a Air Ambulance out of service for 4 hours.

Ok for clerafication so when you say regulator do you mean wall flow meter ? (Ball float / Thorpe tube?) I am betting this is what you mean ... maybe something lost in the language Canukistanian translation .... EH?

Frankly if # 2 is the case this just @ start up and requires a reset every time (ps thats just not making sense to me WTF ?)

I am now leaning towards a faulty pressure sensor then a low regulator setting.

Just for those reading this thread and just FYI stuff.

The regulator part and parcel of the "Main Valve" is a staged diaphragm pressure reduction device ie its does not regulate flow, it regulates pressure and is located IN the Main Valve assembly (the shiny knobby bit) look and one can adjust with an small alan key (with the previso if you can measure the pressure accurately)

So this drops pressure from Main Tank to 50 psi it could be a factory QA error set lower than 50 psi ... I have run into this before (rare) but it can be the source of all evil if it is somehow set lower than the sensor this happens in some older ventilators... usually a head scratcher (and insanity follows to troubleshoot that) and not recommended for those that have access to bio med guys to take a look, due liability issues.

The wall flow meter (Thorpe) only controls flow from wall pressure starting @ 50 and is altitude compensated, the ball is gravity dependent and can be inaccurate (sorry off topic a bit)

For portable delivery of O2 the regulators found (generally) are Burdon Gauge that not only reduce pressure and control flow both (most are used on portable O2 delivery only and are not subject to gravity to give fairly reliable flows and not gravity dependent for delivery of O2.

AK you should see the bloody Russian O2 delivery systems (Black O2 Tanks)... they are the absolute worse to troubleshoot.

But if you still have a problem maybe get a service rep to visit ? :lol: or just change the alarm sensor out, if this is a brand new truck it should be warrentee item I would suspect.

Question remains do you have a minor leak somewhere internal and did you try the leak test (sans alarm)

Seriously with the many systems I have worked with this should not occur unless it is designed to be reset every time on "power up" and that is just a PITA system, then I would have as well implemented your Alaskan flight methodology and bypass/ eliminate the faulty sensor.

OR one could always just turn up the stereo and drown out the noise B) that has always worked for me.

ps But you still need an Canuckstar RT :P

cheers

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