View Full Version : YT Purge
11-13-2006, 07:31 PM
Was sent out on a YT recently. Was informed on arrival that this unit has had a long history of issues including air problems.
So far I've been told it has had new shaft seals and high and low float switches. The unit is loaded with air and I have raised pressure and leak checked. Not even a small trace leak found!
After starting I found the waste air solenoid is not being energized. Checked the solenoid and check valve and both are fine. Started the machine with vanes closed hand jumped the solenoid manualy as tank pressure rose and the rest of the system operates ok. Ran the micro board through test sequence and it cycles the relay output board normaly in test but won't drop the signal during operation. Tank transducer signal matches tank pressure.
Any help or ideas would be appreciated. Waiting on oil sample results!
11-14-2006, 10:48 AM
With machine running, scroll thru the "Display-Data" and watch the purge pressure, it vents @ 35PSIA on a standard purge, much higher on the assisted purge.
You can tell how much non-condensables are present by how many times it "Poots" on each fill cycle...
10 poots a fill and you are loaded with air, as the air is purged out, the number of "Poots" per fill should drop to zero, assuming no leaks are present.
11-14-2006, 02:08 PM
This has an assisted purge. I wasn't aware the tank pressure would be higher I've had it up to 60 and did not call for an exhaust. Any idea what pressure would be?
Thanks for the reply.
11-14-2006, 09:12 PM
If im not mistaken exhausts at 90
11-14-2006, 09:45 PM
If thats right it would explain why I have not seen it exhaust since I've been shutting it down at a little over 60. I guess patience really is a virtue. Thanks!
11-14-2006, 11:20 PM
The suction L, of course, and the handhole plate on the drop leg.
Get a 3/4" breaker bar and the right sockets and work your way around both ends of the suction L. Also, the bonnet on the equalizer vent solenoid sometimes comes loose.
Check to see that there's good cooling of the purge tank with liquid refrigerant. There is an orifice on the top of the purge tank where the little liquid line from the drop leg hooks up.
Have also seen the fart solenoid hang open and you won't build enough pressure.
Have also seen dry shaft seals leak in but not out. May want to have a look at the seal cavity pressure.
Welcome to low pressure...
11-14-2006, 11:51 PM
Flapper leak. It sucks but does't blow under pressure.
11-14-2006, 11:52 PM
Cut the insulation back from the suction L and no trace of leak, purge works great when manualy forceing the exhaust soleniod (jumper), told the customer today that the unit is tight in off and positive but will need to get the purge going or put aftermarket purge on unit to remove air so unit can be run to check drive seal in operation. Will be testing input board tommorow. Want to be sure that the high float switch is not stuck. I find it amazing that York or sorry (JCI) won't respond to tech support questions. Don't have that problem withn Trane or Carrier but oh well. This site is proving to be one of the best supports around.
ONCE AGAIN THANKS FOR YOUR INPUTS!!!
11-15-2006, 02:06 PM
install a new purge solenoid and check valve and you should be ok!!!
11-15-2006, 06:33 PM
Had already checked the solenoid and check valve and both were ok. RichardL and hvacr got me going in the right direction, 90 psi and exhaust energizes. Now I just have to wait for oil analisys. Have little doubt its going to show high moisture since the sample is visually questionable.Just have to take it a step at a time. This unit has had a lot of hands on it and I'm really trying to be do it right.
11-15-2006, 11:24 PM
A while back one of our YT's had the upper magnetic doo-hicky switch stick, and the symptom was an oil fart. It would keep filling and farting. This was the old style lower pressure type. Played hell replacing it, as I recall. Ended up using that 3/4 breaker bar and a truck dual socket to break it loose.
I only have one machine with the "high pressure" purge.
Be sure the gas from the condenser is getting into the purge.
There is usually a strainer and check valve on the gas line.
Be sure the tank gets to a pressure lower than condenser when it empties down to the lower level switch. You may want to put a gauge on it to see.
11-16-2006, 08:16 PM
Purge is working great and I located the manual for the turbo in one of our manuals. Its working almost to the letter! I missed one spot on the initial look but caught it before leaving. The evap sight glass has a residual line on it that on a glance looks like the refrig level. When you take a close look youn can see its just a mark on the glass and the refrig is lower and looks like the water in the Mississpi river. (light brown mud)!!!!
Told the customer that the heads will need to be pulled and eddie current run and tubes and tube sheets checked!
Oil sample was sent for analysis but it looks and smells like used deisel oil. I imagine a major overhaul is inevitable!
While checking the unit found the CW diff switch was out of adjustment and was always closed. Got to love those five minute PM's.
11-17-2006, 08:39 AM
You should be able to set up a dial indicator and just bar the shaft in and out for a reading. Get the specs for your model from the York/JCI rep, if they will tell you. usually, it's around .012-.015, but they're not all the same.
No, it doesn't tell you everything, but it's a good place to have a look.
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