i have (2) 211 hydros install in 2 different location that keep faulting out on los. both are installed under the 2010 code and have the wiring change done. one we have shut off the LOS parameter, the other we are trying to troubleshoot. i can have this thing run for weeks with no issue the it will fail 2 times in the same week then it will go away. i have added a secoundary external thermal overload, no help! i have put test meter in line to watch voltage and have seen the voltage drop all the way from 120 vac to 10 vac but the fault has not happened( odd ). the one that is running does not have a REM unit hooked up and does not have the oil sensors in the tank, i have extended run times to double.
was wondering if anyone has had this happen on the new stuff under 2010 code? don't know if it is the wiring changes they have done or ?????

could it be false tripping the sensor when the unit try's to warm the oil.

Just cause they shut down with a particular code displayed sometimes that is just the first on the list and isnt relevant ...do you know when they were in stalled..,? We just updated some softwear on a 211 with the same problem
..it went away

one was installed 5 months ago the other maybe less then a year.
i have not looked into cold oil but i will see if they have it on or off.

On the main I/O board there is a point between J64/65 which will allow or not allow for a lo oil sensor...tank sensors are known to have problems..with unit at the bottom floor..sensor must be submerged in oil..if not car will run and cpu will generate this fault...

no tank sensor and the jumper is in the correct spot.

Sounds like You're not driving the car up, so its mlt'ing (los). Go through your up section and t/s to see what is preventing an up run or an up run in leveling. I would look at your up limit sw's first. Then check to see if bypass is set correct (size the valve) On new installs lately or mods guys are just throwing the valve in as is. The other possibility but not likely is your thermal overload opening. Check the temp of the m/r and oil.

(sccjr) i have checked switches, have not been threw the valve. in your opinion would it be that intermittent? the elevator will run for 4 to 6 weeks no issue, then it happens maybe once or twice then goes away for awhile???? this is a 211 with COURION fright doors. oil is never hot and m/r is cooled.

Is it being overloaded? Check your relief pressure.

Did you check to make sure the battery jumper is on .....if it is not and you have power issues los will come up as the fault

greenpants this i an 8000lbs car, but ihave asked the question about weight, i seems to do it when no one is using it like a voltage drop never have anyone get stuck and then go out of service. always find it dead.
tony i will recheck the battery jump, but i think i have been over all that with the tech people.

Hello
I can help you with this problem.
I am a Otis Employees and have been working in the trade for 26 years.

The problem as you said has not happened under usage,
It actually happens upon relevling.

It can happen when hot or if sensor is set too high but you have stated those have been accounted for.

Its in the valve but not what someone else may have already said it was.

Its seapage in the down speed and down leveling seals.

Have a seal replacement kit installed for the pair of down vales and your problem will stop.

If you can tell me the name and numbers on your valve, I can tell you the seal kit you need.
Most likely a Maxton UC4.

Let me know.

Rick

JREP would this cause the oil to look milky? like when your sucking air? oil looks like it has been sucking air, also i have never seen the car relevel. also just throwing this out, another mech. was on site this week messing with the freight door(locks) and tripped LOS, he thinks it tripped while the car was at the floor with doors open?????? called "role" then sent a new door board? i have not installed this yet, i think they are just trowing parts at this but have no idea what it is. Do you know when the did the wiring change for 2010 code the way the did? all i can see is the put more "breaks" in the wire but they didn't need to add the plug at least not for any reason i can figure out.
To finish i will order a rebuild kit just incase and yes it is a uc4.

JREP are saying that the code can sometimes be a little ambiguous like alot of fault codes?

The fault log could interpret it as 'low pressure oil sensor'?

ie not enough pressure to hold down control?

Its interesting that you would say the oil in the tank appears milky, as now that opens up a whole can of questions.
If there is air or water in the jack it certainly would create all kinds of problems.
Just to note, the car would still relevel with the doors open as its still in the door zone where relevling occurs.

Now as for the milky looking oil.

Can you tell me if the milky look of the oil occurs during normal operation as in a full run IE top to bottom.
Does it appear only when the car lands and stops then the milk appears??
After the oil settles and the car has not run for several minutes, is the oil still slightly discoloured??
How old is the oil in the tank??

When did you first notice this milky oil??
Has the oil ever been contaminated by anything that you know of despite how little it may have been.
Is the jack completely in the ground and how old is the job??
Is there ever been any oil loss recorded??
Plz let me know if your able to give me answers on some or all the questions.

Talk some more.
Rick

job is only 6 months old so there is little chance of contamination that i would know of unless something was in the jacks, it is a holeless system. get the most milkly ness when the elevator is in leveling/bypassing back to the tank. up or down does not matter. this has been like this from install. packings are leaking and have been from install because we don't change them before we turn it over!!!

I've run into this milky discharge from a maxton valve during leveling before. It was causing inaccurate relevels, and poor stopping consistency. It ended up being a bad o-ring under the up block. Installed an o-ring rebuild kit and a set of new stems and it went away. A second similar situation a few years back revealed a crack in the custom welded pump pipe just before the valve inlet. Some hack-ass smaller outfit here in socal installed a uc4 in a dmc where an I-2 used to be. I know you're all thinking yeah! those old dover valves blow, id

be happy for an upgrade. But not when it's crammed in the tank with 6 thin wall 2" pipe 90's added to get it in there, all welded together with probably a harbor freight pile of junk 110vac buzz box. What a mess. Beware building owners, you definitely get what you pay for in this trade.

LOS tripped again, replaced the power supply board (PSB) found a bad R3 resistor. see if this does anything

Even thou it is relatively new, replace the leveling adjustment and see if the problem goes away. There is a non-replaceable spring in that adjustment that breaks. When it breaks, you dont get stable leveling and you may be drifting below the floor and not getting back due to a broken spring.