My Carrier brand 5 ton heat pump system stop cooling. It is the downstairs system. The upstairs unit is 3 tons and is working well.
Because I have an “open concept” home architecture style, there is a long stairway and a balcony that creates a huge high and open area between the upstairs bedrooms and bath and down to the main living areas of the first floor.
Because cold air is heavy and sinks to lower areas, the upstairs three ton system can condition the entire house to our usual 76F setting.
The house is 100% electric and is super insulated.
Shorten a very long story.
I had several “Big Advertiser Dallas, TX” HVAC companies inspect my downstairs system. A#1 Air and Baker Brothers. The main two in Dallas.
Both sent “sales technicians” rather than a front line service repair person. They do no repair but inspect the problem. Their Modus Operandi are both the same. Your system is over 10 years old, and has the smallest leak, everything needs replaced. Meaning total system replacement.
Both arrive with refrigerant leak detectors strapped on their hip like a Texas cowboy. (I am being a bit “figurative” here…) But I said I had a leak when I called for service. They examine everything for leaks.
There was evidence of refrigerant oil on the indoor coil and a positive leak detection I witnessed. Yes, there is a small coil or more likely, TX valve connection leak. I have known about it for decades. I check system and add refrigerant about once a year. A very slow leak. But it was time to get it fixed. I know it’s a lot of work to get to the source.
I am a 60+ year experienced top level seasoned EXPERT in HVAC and have “done it all.” (Don’t tug on Superman’s cape, spit into the wind, pull the mask off the old Lone Ranger, or mess around with (Slim) er… Dan” –Jim Croce
This first contact person is a blatent attempt to sell new systems. Not make repairs. They arrive in a vehicle (like a PU Truck) with no tools or materials for repairs. (Lesson – Never mention you know you have a leak!)
I first get on the spot quote offers from both companies for complete system replacement ($10K-12K), but Baker Brothers also offered to replace just the entire indoor air handler. Not offering repair to the existing coil (even if possible). As I say, this is the typical M.O. I would continue to use the existing outdoor unit. No service repair. Just equipment replacement. Excuse: “Well, you get a new equipment warranty.” “Repairs are not warrantied.”
So, neither offered to repair existing system or even to look at the TXV for the leak. I always expected this, and was why I simply kept a watch on system charge.
If oil drips from your car one drop per week, you keep an eye on oil level. Not have the entire engine replaced, Uh… maybe that’s how they handle oil drips these days… (?)
The indoor air handler was original to the house. The old system was R-22 refrigerant. Now outlawed and unobtainable. The coil was changed (bigger) and a R410A TX valve added. about 15-20 year ago by A#1.
It was time to get this tiny leak fixed.
The label on the indoor unit still said R-22 and the A#1 service “quote tech” told me it was impossible to repair an R-22 unit. Hell, they installed the conversion to R410A refrigerant. Cross A#1 off my list.
I opted to change the indoor air handler for a Lennox unit from Baker Brothers, at $6500 worth. (OUCH!) The 25 year old fan motor would probably fail next week. (my private thought).
Replacement went well enough.
But refrigerant system preparation was slightly below standard practice. They did not remove / reclaim the existing refrigerant. They let the outdoor unit pump down and store existing refrigerant. This is SOP for a good clean system. I did not observe a high vacuum pump-down of the new Fan coil and line set, as I was not monitoring the entire process. So that may/should/must have been done. I did see a power cord strung from my back porch to where the work area is, and I assumed it was for the evacuation pump.
When I asked, they told me they saved the old charge in the outdoor unit. They were recharging the system at this point and seemed to be having trouble getting the correct pressures and superheat. No confirmation of the vacuum pump-down.
I was mentioning things like possible non-condensable in the old charge since the system had previously lost its charge. They had no idea what I was saying.
(Truth is – the actual problem may be a slow running compressor – read further…)*
Eventually they decided all was well, cleaned up and left the job as complete.
When I personally did this kind of work, standard practice was to replace the liquid line refrigerant filter. It helps capture moisture and contaminates circulating in the refrigerant caused by opening the sealed system. In Heat pump systems this filter has a two way check valve as flow through it reversers between heating and cooling. (Half the filter area is used for each direction) This filter was NOT replaced as it should. It’s more expensive than the standard cooling only one way filter.
The new system operated apparently well for the first week after replacement. Or appeared to. The indoor fan was cycling on set temperature. I could see the outdoor fan running. But latent heat (moisture) seemed high to me.
I went outside and inspected the outdoor unit. The top fan was running but the compressor was not.
I examined the service valves as I touch both the liquid line and suction lined for relative temperature as a measure of operation. Both were at ambient temp, meaning the compressor had not been running.
But then I noticed the access/system valve stem caps and the service port caps were ALL loose. I easily removed all four with my fingers.
They should be closed tightly with a wrench to prevent leaking around the valve stems or service ports. A wrench is ALWAYS required to remove these caps.
Dare I say, the installer screwed this up (loosely) and left a possibility leak source.
I call Baker Brothers for what should be an in-warranty system charge loss. And of course look for other possible leak sources or problems.
I shut off power to the outdoor unit as the compressor was off on internal overload temperature switch (a safety feature on all hermetic compressors) An error code in the Carrier control board blinks a code that tells me the service problems.
This was a Friday evening at 7:30 PM. I decided to wait until Monday. The house was cooling well on just the upstairs unit. This would let the downstairs compressor cool down all weekend and overload reset before the service person arrived.
A Real, properly equipped service person from Baker Brothers arrived (driving a service van with tools and parts) about noon on Monday. He immediately wanted to examine the outdoor unit. I invited him in first, as I wanted to explain the operation. Strange that he didn’t want to talk with me first. First rule of good service is ALWAYS talk to the customer first.
Then we went outdoors to the unit. I explained how I found the valve caps all loose and unsealed. Now the rest is up to him to diagnose and repair. I step away.
* He took the electrical panel cover off and examined the electrical system. There is a dual section capacitor in there. One section is for the compressor and the other is for the fan motor. A service tech years ago must have replaced the capacitor. There was a second capacitor piggy backed to the large capacitor with a plastic zip tie wrap. It was wired in parallel to the compressor side of the dual capacitor.
This is very unusual but I assume the service tech at that time did not have the proper value dual section capacitor. Capacitors wired in parallel ADD their values, so the previous tech created the value he needed for the compressor, by adding the 2nd capacitor. I knew this was done, but never realized the long term problem this may create. Read on.
It was now clearly evident this day, the added capacitor was bulged out of shape. This is a common failure indication and actually opens the circuit within the capacitor.
This failing capacitor is probably one of the main problem of the system all along. I knew for years there has been a very slow minor leak upstairs. The one discovered in the original air handler. But no evidence of the failing added capacitor.
The compressor, now operating with only the original but lower value capacitor, was now running slower and over-heating the windings causing the internal thermal overload in the compressor to operate. In fact, was operating as a much lower capacity compressor and therefore producing confusing system refrigerant charging readings. eventually shutting off on internal compressor temperature.
There is no reset button. One must wait until the compressor gets cool enough to self reset this overload. Long periods (hours) of compressor not running. (But the outdoor fan will be running if there is a call for operation)
This new (to my equipment) inspection by this service tech immediately identified the faulty capacitor. It finally expanded and took itself out of the circuit. Now making it easy to spot. I give him full credit for recognizing what he observed! However, I suspect he had no idea about why it was wired as it was. (Two capacitors in parallel.)
It took him almost two hours to replace the dual section capacitor. I don’t know what his problem was but he ended up cobbling up an awful looking two capacitors similar to the first. I watched him struggle with the wiring as I walked away to let him do HIS job. He either did not have the correct value dual capacitor or was afraid to wire it differently than he found it. There is a schematic showing proper (factory) wiring on the access cover.
Cobble Job
He got it wired and the compressor running at full normal speed and capacity. The charge was low. I can surmise the original installers may have under-charged the system because of the slow running compressor. (The problems they mentioned in getting the readings they expected.) The new technician said he put 40 or some more ounces of refrigerant in the system. (2.5 pounds) Ounces sounded strange. I always talked in pounds and fractions. But hey, it’s a new age… they can sell it $5.00 an ounce instead of $80 a pound. Dealer R410A actual cost is $11.16 per pound.
So, perhaps there was no “new” leak after all. Just an undercharge when getting the system operating with the new indoor air handler. The installers TOLD me something wasn’t right when recharging. The capacitor issue could not be detected visually at that time.
BUT, the new service tech said he discovered a leak in the outdoor coil. Impressive, that’s hard to do. I said, “Show me.”
He had his gauge set hanging on the side of the unit as most service techs, including my self, do. He was probing all around the gage set and between hoses looking for the new coil leak he “just discovered.”
I asked him to please remove the gage set from the side of the unit (where he was probing) and place them away on the ground.
He did so.
After probing 30 or 40 slots on the side of the condenser, he got a quick blink on his electronic probe. “There it is” he exclaimed. But he couldn’t get repeat at that location. He tried a dozen more slots and got two quick flickers in other locations.
He said the leak is extremely small and why its so hard to find in several locations.
(Alarms are going off in my head)
Because… It was a very breezy day. wind blowing between the houses was probably 25 to 30 MPH. It was fluttering my t-shirt, waving the blades of grass and turning leaves over on the trees. (look at my video.)
The service person was probing on the entering air side of the outdoor coil with the fan running. Any supposed tiny leaks would be strongly pulled into the unit and impossible to detect.
He was obviously working on me to replace to outdoor unit.
I told him I wan’t worried about a leak that small.
He preceded to remove his gage set.
He began cranking the stems full direction open and closed while the unit was running. I am thinking. “What the hell? He doesn’t know which way to seat the valves!”
He mumbled something about “making sure all the oil (in the gages?) was returned to the system. He shut off the high side while the compressor was running, then worked the valves on his gages until both were zero (as well as the entire external system. Never saw it done that way or for that reason)
He removed his hoses and tightened the port and stem caps. Ready to leave. I asked him why he left the liquid line valve in the full system off condition.
He got a bit angry and said that how you remove the gages.
I replied, “You must leave the system valves in the full back seated (open) position when leaving the system in operational running condition.
He told me I didn’t know what I was talking about. This was the correct way with the valve fully seated.
Wrong Answer!
So I told him he was not only an incompetent service person (already established by his outdoor leak test procedure) but he also didn’t seem to know which direction refrigeration service valves operate, back seat and front seat.
This was witnessed by his rapid cranking full stroke on a simple service port connection.
I called him out as being ignorant of HVAC service procedures and therefor an incompetent service person.
He said I offended him and I replied “That was my intention.” Then told him to pack up his gear and get off my property.
I’m sure his real goal was for the bonus he would earn for convincing me I needed a new outdoor unit.
If the full front seating of the liquid valve was deliberate and not ignorance it could have been equipment sabotage.
Since the next step in his procedure should/would be to come inside and finally examine the new installation for leaks, the system would be in full pump down. Can’t find a leak with no gas in that part of the system. But I didn’t let him go that far…
Before he walked away, I heard the compressor shutdown in full pump down because of the closed valve.
He walked to his truck and shouted from the street, “How was I going to pay the bill?” I said “send me one!”
I called the Baker Brothers office and asked for the “service manager” (or someone of authority) Someone called me back, quickly mentioned his name, but didn’t identify his position. I assumed the Service Manager.. I explained all I have written here. He said, “What do I want to do? I said. “I will pay only for the capacitor.”
It’s the one problem he got exactly right.
We both agree and complete the call. A while later he (or the office) sends me a non-itemized bill for $599.00! For a $15-$25 capacitor. It was actually an in-warranty call except for the capacitor.
My tiny original leak has now taken $7,100 of my retirement cash reserve. Because “repair” is a lost art.
OK, I see who the hell they are. It’s time for WAR!
Caution! Never choose Baker Brothers for any kind of service. They are only interested extremely high priced replacement new equipment. They don’t have anyone fully dedicated to old school equipment repair and keeping old systems operational. They will lie and cheat the public and sell new full systems if they they can.
I had to break out my prized personal 50 year old ratchet service valve wrench and open the closed high side valve. I could hear the woosh as the refrigerant returned to the system. The compressor was now off on internal low pressure lockout, so I had to power reset the system controls to initiate a compressor restart.
All computer these days. No manual reset buttons.
The system started after the time delay (standard) and was running smoothly. I decided I needed to put on my gages and check refrigerant system operational conditions myself.
Sure enough, He has left the system undercharged. Not by much. The outdoor temperature was now 95 degrees. Maybe a half pound more was needed..
I added some vapor only to get suction return pressure up to 45 degree equivalent temperature to prevent coil frost/freeze. That brought high side up to 110 equivalent degrees on a 95 degree day. Nice heat on the condenser discharge air.
My system is not an accurately factory matched component system. Outdoor is Carrier brand, indoor is now Lennox. Not a critical problem, but “by-the-book charging” may not be accurate. I also know the 7/8 inch suction line for a five ton system with the evaporator 20 foot higher and 20 foot distant from the condenser is undersized. It should be 1 1/8 inch minimum. Result of smaller line is higher velocities and more pressure drop. Oil return is not an issue with the evap. coil at the high point. (not needing high velocity for oil returns)
To Sum-up
The real bottom line problem was the bad or “going bad” add-on capacitor. I had not seen it “puffed” (expanded) on previous checks. Nor had any of the previous (5 or 6) installers and service techs. So the expansion happened in the week after the new indoor unit installation and system refrigerant recharge. Running a motor like a compressor with the wrong value of capacitance causes an improper phase shift causing the motor to run slower and much hotter.
Wiring two run capacitors in parallel is NOT common practice. Usually when a motor capacitor fails as this one did. It fails open and stops the compressor. But with only one of two failing, the motor still has one (wrong value) capacitor trying to keep it running.
This is like forcing a now 3hp motor to do the work of a 5 hp motor. It doesn’t run very long under the load.
In “normal” hermetic compressor operation, the cold low pressure refrigerant gas being sucked into the hermetic compressor is used to keep the motor from getting too hot. In heat pump operation this heat is a bonus and helps make the indoor heating more efficient. In cooling mode it adds to the heat the outdoor unit needs to dissipate to the outdoor air.
Running too slow is producing more heat in the motor and less cooling gas flow to take that heat away. a double whammy. Internal compressor motor temperature limit switch opens, stopping the compressor motor.
Sidenote on Capacitors:
I did some checking on the internet about A/C motor capacitors. Both start and run varieties. A vast majority of the posters explained the capacitor “stores a voltage charge” and that “charge” boosts the motor. Totally false!
Capacitor can store a voltage charge. That is true. But the other thing they do is shift the phase angle of the A/C current and power flowing through them. It’s a reactance (resistance) / capacitance formula of the time value to charge/discharge the capacitor. Capacitors and motor windings create a “tuned circuit”, shifting the 60 Hz sine wave phase angle. (It’s a timing lead/lag change)
In A/C motors the phase angle (timing) is shifted by this tuned circuit enough to look like and operate as a second phase. Non capacitor motors do the same shift using motor winding inductance to create the phase timing shift. It’s not as efficient as using capacitor shift, so only used with low power single phase motors.
Enough science but good HVAC motor technicians need to totally understand this electrical phase shift properly. Motor capacitors are not voltage boosters.
The hard start capacitor is often called a “booster kit. It produces an extreme momentary, large phase shift to get the motor turning, then it must be removed from the circuit. It’s a phase “boost” but not from a stored voltage charge.
OK, Dan the science man, has said enough, But good service people have to know all this science “stuff”. Trouble shooting is not a rote, fixed path procedure. But I know many training systems try to do that. The excellent service person must have a well rounded, total awareness of all variables and how and why every component functions. (like, opening and closing service valves) Also the situational awareness that in many cases, the trouble may not be one single “item to replace.”