Free Packaged 5 ton Heat pump troubleshooting

Geo NR Gee · 02-01-17, 01:18 AM

My 75 year old friend and his cousin have been working in his shop for the longest time without heat. It's so cold inside there that you can see their breath most of the year. I made sure to put on a coat when I went over to visit.

One day after my visit, I was looking through the free ads and found that a local Aerospace company was giving away some 5 ton Trane packaged heat pumps. They had 5 of them and by the time I drove an hour and a half, only one was left. These are 3 phase units and I didn't think they would go that fast.

We hoisted it off the trailer and into the big door of his shop, hooked it up to power and made sure the compressor and the fan turned on. We all agreed that it was putting out heat.

The two of them took their time and after about 6 weeks, they had the unit wired up, ductwork through the wall and into the shop. Inside they built wooden ductwork and painted it gray. I was impressed with the special turning radius that they built into them.

We turned on the breaker, called for heat on the tstat and heard the compressor start up. The shop temperature was 39* F inside and 42* F outside. I left them to enjoy the warmth and within a couple of hours they said it was about 50 and the next day it was 60.

When I came back to check on them, the unit didn't sound like the compressor was on. After going inside I saw that the tstat read backup heat.

Now, these guys are retired and told all their friends that this is the first time in January they didn't have to wear their double coats inside in over 25 years!

The look on their faces when I broke the bad news and told them it was on backup heat was awful.

I got some hvac gauges on the lines and found that the pressures were the same for both the low and high side. Hmmmm. They both showed 132psig and the temperature was 64.5 and 96.7. I have never saw the same pressures before on both the low and high side. Thought about it and wondered is the compressor shot? Is the reversing valve stuck? I didn't know how to troubleshoot them.

We put the unit in cooling mode to see if that would fix it and if we could hear the reversing valve switch and then swoosh like I would normally hear. Nope. That didn't happen either. I took the magnetic coil off the reversing valve to manually move it and that didn't change anything. I checked it with a screwdriver and you could feel the coil pull the screwdriver to it.

Watching a few youtube videos they say to lightly tap on the end of the reversing valve. Nothing changed there either.

Not sure what else to check. Could it be low on refrigerant?

randen · 02-01-17, 08:41 AM

Geo NR gee

Hmm was the compressor running in the proper direction.?? 3 Phase right?? Water to air or air to air.? Ground loop??? was it actually working when it was first powered up or operating on the heat strip??

Randen

Geo NR Gee · 02-01-17, 10:07 AM

Randen,
I assume it's going in the proper direction because instructions I was given was to hook up the 3-phase wires and watch the condenser fan rotation and make sure it matches the directions on the label. This is an air-to-air heat pump.

It was most likely the heat strips we felt when we initially started it. I never put gauges on the unit during initial startup either.

jeff5may · 02-01-17, 02:26 PM

The reversing valve will not operate without pressure differential across it. The compressor discharge line is used to source the solenoid (pilot) valve which in turn controls the main (spool) valve. Since the solenoid coil is energized on command, it is OK electrically.

From your description it seems the unit has fallen into protection mode and is providing emergency heat because something went wrong. Since the unit energized the compressor once, we know the start circuit is doing what it should. What made the unit fall back on emergency heat is the big question at hand. The next time you try to start the unit observe the pressure gauges and power draw. If the thing falls back in emergency heat again in short order, What You observe will narrow down your problem and tell you where to look for a repair solution.

Please provide a model number or picture of the name plate on the unit so we can tell what the design is like.

Geo NR Gee · 02-01-17, 03:33 PM

Jeff5may said "The reversing valve will not operate without pressure differential across it."
Does that mean that the compressor has to have suction on one side and pressure on the other side?

When the unit starts and the gauges are hooked up, it stays the same for the pressure on both sides. The temperatures change though from 40*ish to the upper 90's. It doesn't build pressure.

Model number is

jeff5may · 02-02-17, 12:42 AM

OK, found some literature on your unit. This bad boy retailed for around 6 grand in 2012!

Installer guide:
http://www.climatesolutionsinc.com/w...CZ6-Manual.pdf

Product data and specs:
http://www.trane.com/content/dam/Tra...7_02012012.pdf

Looks like this baby is pretty strong! Trane Platinum XL16 commercial rooftop unit with 2 stages each of heating and cooling (3.5 ton / 5 ton nominal), 16 SEER, 8.6 HSPF ratings. R410a refrigerant, TXV metering for heating and cooling. ECM variable-speed indoor blower. Plenty of options available that we don't know whether or not this unit has. Most important option is LOW AMBIENT COMPRESSOR BYPASS!

If the unit has this BYPASS module wired in, it shuts down the compressor below a set outdoor temp, falling back on installed strip heaters. Certainly works for stage 2 heating, not sure about stage 1 (brief skimming through words). I saw a sequence of operation section in the installer guide, and a thorough reading would clarify that question. I'm sure this unit has all kinds of jumpers and dip switches to set to achieve the desired mode of operation. That's where I'd look first.

Who knows where or how this thing was set up to do its duty in the past? Not me. Once you set the controls to operate how they should in the unit's new location, it might not need more work! This assumes all the wiring was done flawlessly the first time through.

Geo NR Gee · 02-08-17, 11:45 PM

Quote:

Originally Posted by randen

Geo NR gee

Hmm was the compressor running in the proper direction.?? 3 Phase right?? Water to air or air to air.? Ground loop??? was it actually working when it was first powered up or operating on the heat strip??

Randen

My answer to your question above was:

Quote:

Originally Posted by Geo NR Gee

Randen,
I assume it's going in the proper direction because instructions I was given was to hook up the 3-phase wires and watch the condenser fan rotation and make sure it matches the directions on the label. This is an air-to-air heat pump.

HOWEVER, the instructions for startup I was given was incorrect! Randen your first response was the answer. The compressor was going in reverse.

Today my brothers HVAC friend suggested like Randen that it maybe going in reverse. When I told him how we were instructed, he said that the condenser and blower fans are not 3 phase and wouldn't go backwards anyway. He suggested I switch the phases.

After switching two phases, it started heating the space and without the heat strips. The compressor was a lot quieter too! I hope we didn't ruin the compressor? Also is there a proper way to test and see if the phasing is wired correctly?

Thank you to Randen and Jeff5may for your assistance getting this unit up and running again. Speaking for my friends, they are also very grateful. It was really neat to watch a couple of older (70 year old) men happy and excited today about having heat in their hobby shop as they call it. 32*F outside and 60*F inside, they are "Happy Okies" he said.

02-01-17, 01:18 AM	#1
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Free Packaged 5 ton Heat pump troubleshooting My 75 year old friend and his cousin have been working in his shop for the longest time without heat. It's so cold inside there that you can see their breath most of the year. I made sure to put on a coat when I went over to visit. One day after my visit, I was looking through the free ads and found that a local Aerospace company was giving away some 5 ton Trane packaged heat pumps. They had 5 of them and by the time I drove an hour and a half, only one was left. These are 3 phase units and I didn't think they would go that fast. We hoisted it off the trailer and into the big door of his shop, hooked it up to power and made sure the compressor and the fan turned on. We all agreed that it was putting out heat. The two of them took their time and after about 6 weeks, they had the unit wired up, ductwork through the wall and into the shop. Inside they built wooden ductwork and painted it gray. I was impressed with the special turning radius that they built into them. We turned on the breaker, called for heat on the tstat and heard the compressor start up. The shop temperature was 39* F inside and 42* F outside. I left them to enjoy the warmth and within a couple of hours they said it was about 50 and the next day it was 60. When I came back to check on them, the unit didn't sound like the compressor was on. After going inside I saw that the tstat read backup heat. Now, these guys are retired and told all their friends that this is the first time in January they didn't have to wear their double coats inside in over 25 years! The look on their faces when I broke the bad news and told them it was on backup heat was awful. I got some hvac gauges on the lines and found that the pressures were the same for both the low and high side. Hmmmm. They both showed 132psig and the temperature was 64.5 and 96.7. I have never saw the same pressures before on both the low and high side. Thought about it and wondered is the compressor shot? Is the reversing valve stuck? I didn't know how to troubleshoot them. We put the unit in cooling mode to see if that would fix it and if we could hear the reversing valve switch and then swoosh like I would normally hear. Nope. That didn't happen either. I took the magnetic coil off the reversing valve to manually move it and that didn't change anything. I checked it with a screwdriver and you could feel the coil pull the screwdriver to it. Watching a few youtube videos they say to lightly tap on the end of the reversing valve. Nothing changed there either. Not sure what else to check. Could it be low on refrigerant?

02-01-17, 03:33 PM	#5
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Jeff5may said "The reversing valve will not operate without pressure differential across it." Does that mean that the compressor has to have suction on one side and pressure on the other side? When the unit starts and the gauges are hooked up, it stays the same for the pressure on both sides. The temperatures change though from 40*ish to the upper 90's. It doesn't build pressure. Model number is Attached Thumbnails

02-01-17, 08:41 AM	#2
randen Uber EcoRenovator Join Date: Apr 2011 Location: Strathroy Ontario Canada Posts: 657 Thanks: 9 Thanked 191 Times in 129 Posts	Geo NR gee Hmm was the compressor running in the proper direction.?? 3 Phase right?? Water to air or air to air.? Ground loop??? was it actually working when it was first powered up or operating on the heat strip?? Randen

02-01-17, 10:07 AM	#3
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Randen, I assume it's going in the proper direction because instructions I was given was to hook up the 3-phase wires and watch the condenser fan rotation and make sure it matches the directions on the label. This is an air-to-air heat pump. It was most likely the heat strips we felt when we initially started it. I never put gauges on the unit during initial startup either.

02-01-17, 02:26 PM	#4
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	The reversing valve will not operate without pressure differential across it. The compressor discharge line is used to source the solenoid (pilot) valve which in turn controls the main (spool) valve. Since the solenoid coil is energized on command, it is OK electrically. From your description it seems the unit has fallen into protection mode and is providing emergency heat because something went wrong. Since the unit energized the compressor once, we know the start circuit is doing what it should. What made the unit fall back on emergency heat is the big question at hand. The next time you try to start the unit observe the pressure gauges and power draw. If the thing falls back in emergency heat again in short order, What You observe will narrow down your problem and tell you where to look for a repair solution. Please provide a model number or picture of the name plate on the unit so we can tell what the design is like.

02-02-17, 12:42 AM	#6
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	OK, found some literature on your unit. This bad boy retailed for around 6 grand in 2012! Installer guide: http://www.climatesolutionsinc.com/w...CZ6-Manual.pdf Product data and specs: http://www.trane.com/content/dam/Tra...7_02012012.pdf Looks like this baby is pretty strong! Trane Platinum XL16 commercial rooftop unit with 2 stages each of heating and cooling (3.5 ton / 5 ton nominal), 16 SEER, 8.6 HSPF ratings. R410a refrigerant, TXV metering for heating and cooling. ECM variable-speed indoor blower. Plenty of options available that we don't know whether or not this unit has. Most important option is LOW AMBIENT COMPRESSOR BYPASS! If the unit has this BYPASS module wired in, it shuts down the compressor below a set outdoor temp, falling back on installed strip heaters. Certainly works for stage 2 heating, not sure about stage 1 (brief skimming through words). I saw a sequence of operation section in the installer guide, and a thorough reading would clarify that question. I'm sure this unit has all kinds of jumpers and dip switches to set to achieve the desired mode of operation. That's where I'd look first. Who knows where or how this thing was set up to do its duty in the past? Not me. Once you set the controls to operate how they should in the unit's new location, it might not need more work! This assumes all the wiring was done flawlessly the first time through.