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Originally Posted by timebuilder

That's right. If you order a repalcement enthalpy sensor for an older unit, you get the newer version. It looks like the photon torpedo casing from the Star Trek movies.

Here is what I found. Maybe it should say, "reubicar a la campana de aire fresco."

Attachment 305651

that most be old inventory, the new ones came with the "photon torpedo" sensor, I dont believe it was made by Honeywell.

Wow,

Originally Posted by valdelocc

I installed couple of predators a week ago, didn't see the "sticker with big English letters" but noticed the enthalpy sensors are now smaller,gray and made in Mexico.

That's right. If you order a repalcement enthalpy sensor for an older unit, you get the newer version. It looks like the photon torpedo casing from the Star Trek movies.

Here is what I found. Maybe it should say, "reubicar a la campana de aire fresco."

Attachment 305651

Originally Posted by timebuilder

I have seen an identical unit with the second stage on the bottom of the evap. Same situation, but this unit does not trip the pressure switches. That said, it WAS an installer cluster.

I looked at the economizer, to make sure it has been set properly. Now, York puts a sticker on the enthalpy sensor, in big English letters, telling the installer to relocate the sensor to the fresh air hood.

Now, if you don't speak English, that label means NOTHING.

There is was, staring me right in the face, and impossible to miss.

IF you speak English.

So I finished the job our Home Depot laborer of the day did not, and I also corrected the baro damper, too.

I'm getting sick of this nonsense. Get a bus and fill it, for heaven's sake, and get some Americans working.

I installed couple of predators a week ago, didn't see the "sticker with big English letters" but noticed the enthalpy sensors are now smaller,gray and made in Mexico.

I had on doing that a while back. It was a faulty limit switch losing 24vlts to condenser fan contactor. I could tech across and it would be fine, then push on my terminals and it would read open. Check your 24vlts and safety's

Originally Posted by Hildy5652

Hello Spears Group,

I'm sure you have resolved this problem by now as well and I appreciate your correspondence when this happened to me back in June.

Better late than never: we found the problem with this York Predator a whior back after my posts and just wanted to add this for future information. The problem existed from the York factory. We found the liquid lines and evaporator lines switched between circuits. It wasn't so obvious at the time especially being newly manufactured and new condenser coils and such. This did make me wonder why York never got involved with the problem. Did this happen to a single unit or a whole run at the time of production. I'll never know.

was the liquid line from compressor "A" feeding evap. coil "B"?

I have seen an identical unit with the second stage on the bottom of the evap. Same situation, but this unit does not trip the pressure switches. That said, it WAS an installer cluster.

I looked at the economizer, to make sure it has been set properly. Now, York puts a sticker on the enthalpy sensor, in big English letters, telling the installer to relocate the sensor to the fresh air hood.

Now, if you don't speak English, that label means NOTHING.

There is was, staring me right in the face, and impossible to miss.

IF you speak English.

So I finished the job our Home Depot laborer of the day did not, and I also corrected the baro damper, too.

I'm getting sick of this nonsense. Get a bus and fill it, for heaven's sake, and get some Americans working.

sons of $@#!

Resolved York Predator ZF120

Hello Spears Group,

I'm sure you have resolved this problem by now as well and I appreciate your correspondence when this happened to me back in June.

Better late than never: we found the problem with this York Predator a whior back after my posts and just wanted to add this for future information. The problem existed from the York factory. We found the liquid lines and evaporator lines switched between circuits. It wasn't so obvious at the time especially being newly manufactured and new condenser coils and such. This did make me wonder why York never got involved with the problem. Did this happen to a single unit or a whole run at the time of production. I'll never know.

Originally Posted by The Spears Group

We are experiencing the same issue with the ZF120. We have narrowed our symptoms down to: When 2nd stage satisfies, the head pressure for stage 1 goes up to near or over the cut out of 650 momentarily and then slowly drops back down. Tech support had us install a time delay to hold the HPS in the circuit till the head drops back down. We tried this but we are still getting sporadic nuissance trips. We jumped stage 2 with stage 1 for the time being till we can resolve the issue. I try to grasp everything I can with thoughts of possibly with this micro-channel coil....stage 2 runs it's course, coil heated up, aluminum micro-channel coil expands, then when it shuts down it cools off and contracts to original thickness, allowing more air through stage 2 coil that is not needed, making stage 1 coil (that is still running) only getting say 80% of the airflow required, in turn increasing the head pressure. Just a thought. I will let you know what our resolve is hopefully by days end.

Interesting problem...

Each circuit is totally independent with the exception that they share the same air (and fans) entering the condenser coil. So if we're dealing with an intermittent part failure, it is duplicated - rare, but not unheard of.

Pressure Switch - verify the correct tripping pressure and not just what is stamped on the switch. 625 +/- 25 psig

Condenser Fan Operation - it appears you have verified operation and witnessed a high-pressure fault, with the fans running (in correct rotation / blades secured). I'd thoroughly check and rule it out.

Metering Device - I would think if there were a problem here, it would be trying to pump down, but you have also replaced them.

Restricted Condenser Coil - bearing in mind that the circuits are independent it seems a far stretch that a plug was left in both of them at the factory (not impossible). I would think that if there were a plug, it would eventually find a spot in the coil to stay lodged and make the problem permanent. If there was a mfg defect, it would seem that the problem wouldn't be intermittent. Oil is a variable and it is possible that both compressors were overcharged with oil but I would think the oil would eventually interfere with the operation of the metering device.

Compressor - again, anything in this part is happening to BOTH compressors and intermittent. Only thing I can think of would be sticking discharge valve, but I also believe it to be highly unlikely.

I'm with timebuilder and would like to see some system readings when it is operating correctly. What are the compressor model numbers?

TXV/TXVs sticking shut.

Originally Posted by Hildy5652

Here's what happens... The first stage of cooling starts and trips the high head pressure control within 3-4 seconds. The unit is new. This locks out the unit and after restating sometimes it starts and runs for days. Then without apparent reason the situation reoccurs. It's charged with 410A. The York service representative has little input. Blames the situation on airflow. He says, York has no history with those symptoms with that model. We have jumped out the condenser fans to run as the unit starts. The blower runs as the the cooling begins. We have checked strainer, driers and changed expansion valves. I would think its something inside the condenser but the same thing happens to stage two as well. We have recovered refrigerant and recharged to manufactures nameplate specs. This happens whether it is 85* or 70*.... If you need more info..let me know..thanks. If this hasn't happened to someone.. It's difficult to troubleshoot since it has no history or normal diagnostic parameters.

Sounds electrical. Like the HP switches are rated for R22.

If youve confirmed pressures then possibly fan motors not starting when compressor starts.

We are experiencing the same issue with the ZF120. We have narrowed our symptoms down to: When 2nd stage satisfies, the head pressure for stage 1 goes up to near or over the cut out of 650 momentarily and then slowly drops back down. Tech support had us install a time delay to hold the HPS in the circuit till the head drops back down. We tried this but we are still getting sporadic nuissance trips. We jumped stage 2 with stage 1 for the time being till we can resolve the issue. I try to grasp everything I can with thoughts of possibly with this micro-channel coil....stage 2 runs it's course, coil heated up, aluminum micro-channel coil expands, then when it shuts down it cools off and contracts to original thickness, allowing more air through stage 2 coil that is not needed, making stage 1 coil (that is still running) only getting say 80% of the airflow required, in turn increasing the head pressure. Just a thought. I will let you know what our resolve is hopefully by days end.

What is the pressure on your gauge when the HPS opens?

What is the condenser delta T?

What are your superheat and subcooling when it runs?

Yes sir, we have done exactly that. We thought factory overcharged. We subtracted refrigerant when recharged and it ran ok until it was cooler at night then locked out on freeze stat. Yes, it is a micro channel coil. We wonder if oil is slugging the condenser and simulating a restriction temporarily and when it clears the operation sustains. I don't know if the manufacturer specifies the amount of oil the compressors operate with or it is the compressor maker. Also, it's funny York has no input with the problem. I'm starting to believe oil is the problem. And now wonder if the unit trips after long off times and the oil migrates from the compressor into the condenser channels.

Recover the charge.Scale back in minus 1 lb. per circuit and check superheat and subcooling.I would be curious of the outcome.(is this a Micro fin coil?)

Thanks for your reply. We have verified the pressures are at the safety limits of 410A and the h/p switches are preset for 410A. Even if they were set for R-22 they would trip consistently, which is not the case. Sometimes the machine starts out normal and sometimes it shoots to cut out pressures within seconds. Because it doesn't happen every time, as soon as it operates normally... what is there to look for ? It has to be something within the manufacturing. I have thought of a pressure test plug within the piping and lodges itself whenever... But it happens to both stages at the same time after the compressor starts.

I would place a tattle tale across the HPS to verify if they are opening, also check the ratings, maybe by mistake they installed r-22 safties, it happens.

Here's what happens... The first stage of cooling starts and trips the high head pressure control within 3-4 seconds. The unit is new. This locks out the unit and after restating sometimes it starts and runs for days. Then without apparent reason the situation reoccurs. It's charged with 410A. The York service representative has little input. Blames the situation on airflow. He says, York has no history with those symptoms with that model. We have jumped out the condenser fans to run as the unit starts. The blower runs as the the cooling begins. We have checked strainer, driers and changed expansion valves. I would think its something inside the condenser but the same thing happens to stage two as well. We have recovered refrigerant and recharged to manufactures nameplate specs. This happens whether it is 85* or 70*.... If you need more info..let me know..thanks. If this hasn't happened to someone.. It's difficult to troubleshoot since it has no history or normal diagnostic parameters.

How about some more info.

Condenser delta T?

Superheat and subcooling?

Estimated time of day when this happens?