Trane CVHB Loss of motor coolant

[Greg D]

Looking for feedback if anyone has seen a trane
cvhb lose motor coolant while rest of the machine runs normally? There is no restriction in supply line off economizer, both orifice plates are clean. liquid appears to be flashing right out of economizer on motor coolant line but evap level seems fine. Any input appreciated, Thanks, Greg

[Healey Nut]

Does the motor cooling line have a sight glass on it, is there a drier or filter shell in the line , whats the symptoms . Readings would help too

[Greg D]

There is no sight glass on the supply line, there is a sight glass on the return that is completely empty. there is a single core drier housing with a filter in the supply. I tried removing the filter and running the chiller without one but there was no change. I ran a 1/4 inch hose frome the filter housing to the evap and was unable to establish a steady stream of liquid. Everything looks normal except the motor is overheating. I seem to be flashing before I get to the filter. Thanks

[Tech Rob]

What's the system differential pressure? What are your entering condenser and chilled water temps? Do you know that the motor is actually overheating, or is it a sensor telling you so? Could the machine be extremely low on charge?

[Greg D]

condenser water was around 75 in and 80 out. Cond. pressure was 3# , Chilled water was 48 in, 41 out. Evap presure was 15 or 16". The motor tripped the High motor temp switch on the customer and was still 150 degrees when I arrived. I monitored it with an infared when I ran it an it's definitely getting hot. I pulled the charge and got out 2350# , The name plate charge is 2500#. I'm sure I left a hundred in the machine so I don't think the charge was an issue. The machine put out 41 degrees without problems the previous 24 hours.

[lunchbox]

I have heard of one machine that had similar problems. The chiller had had a regasket about 6 months prior. They ended up tearing the chiller back down and found a rag that had accidentally been left in the condenser. It had migrated to the orifice plate and partially blocked it causing a motor overheating problem.
Not sure if it even helps, but it is a good story.

[Tech Rob]

Well, that's a weird one. Condenser approach seems a little high, but I don't think that is the problem here. Seems like there is a blockage, restriction, or kink, or something of that nature.

[Nuclrchiller]

When you pulled the charge, how do you estimate how much is left in? And why was it left in? Why go that far and then stop? Were those readings from the control panel? Is the control panel UCP1? Suggest backing up all readings with your test instruments. You mention no problems the previous 24 hours - why was this timeframe mentioned? Did something happen prior to that, like chiller was rebuilt or started after a long downtime? What is temperature of motor cooling supply line?

[Tech Rob]

Maybe the gauges he is looking at are showing 16" and 3# because they have been showing the same pressures for 25 years and now they are stuck... lol

Maybe the actual pressures are more like 10" and 6", and a pin broke off in the vane linkage and now the machine is running with next to no differential pressure to move the motor coolant around and the inlet guide vanes are completely closed. It's no more strange than the thread where the pre-rotation vane shaft disengaged from the vanes on the York YT and the machine was running with them all the way closed.

Or maybe it's just a rag.

[jayguy]

...The chiller had had a regasket about 6 months prior. They ended up tearing the chiller back down and found a rag that had accidentally been left in the condenser....

it was 45 minutes later....and STOP BRINGING IT UP! i have heard enough of it already! (it only happened 1 more time since then but i had an apprentice that appearantly i wasn't watching enough.)

one of the guys at our shop had a 6 year old CVHE that had never been opened up lose all of its oil pressure in 1 night. after several days of trying to figure it out, we found the oil supply line completely plugged with a 515 slug that was 6" long...no idea how it got there, passed the oil pump or anything...never had the problem since in any machine configuration.

[lunchbox]

it was 45 minutes later....and STOP BRINGING IT UP! i have heard enough of it already! (it only happened 1 more time since then but i had an apprentice that appearantly i wasn't watching enough.)

one of the guys at our shop had a 6 year old CVHE that had never been opened up lose all of its oil pressure in 1 night. after several days of trying to figure it out, we found the oil supply line completely plugged with a 515 slug that was 6" long...no idea how it got there, passed the oil pump or anything...never had the problem since in any machine configuration.

So now that is twice it has happened????

[jayguy]

So now that is twice it has happened????

that you know of!

[tcy612]

Keep us posted on what you find Greg...

[lunchbox]

that you know of!

At least you didn't leave the plug in the oil drain hole for the journal bearing in the motor on a CVHE and realize it AFTER you had the gas back in it and was about to start it up.

[acjourneyman]

At least you didn't leave the plug in the oil drain hole for the journal bearing in the motor on a CVHE and realize it AFTER you had the gas back in it and was about to start it up.

Hey, I have been there, but at least I was the apprentice.

[acjourneyman]

I would try to find out where exactly the gas was flashing off and try to pinpoint the blockage.