Possibly overcharged.
Possibly a failing compressor.

 

If it is overcharged, then is it doing harm to continue running it before the tech gets a chance to come over, or is something preventing the compressor motor from coming on until the pressure is low enough to safely be started up?

 

Tech was back yesterday. He reduced the refrigerant level slightly and, so far today (currently 86 degrees out), the compressor has been starting fine. However, in my opinion, this unit (we have two) doesn't cool as well as the other identical unit due to the slight reduction in refrigerant. If I'm understanding the issue of it having the delayed start correctly, from speaking to the manufacturer, there is a thermal overload protector, and once that gets tripped it has to cool off for a period of time before it automatically resets. If this was the issue causing it to have a delayed start with the higher refrigerant level, then I'm confused as to why the thermal overload never tripped while the motor was already running. It was only a delayed start up. When it failed to start, I could not hear it trying to start up and then being shut off. It just would just fail to start up for as long as 25 minutes or more. This was even occurring (with a lessor delay) when it was upper 60s outside. Is it possible for the temperature of the motor to rise briefly after being shut off due to the fan no longer spinning and that is when the thermal overload protector was being triggered? Just trying to understand how if it was a thermal overload protector it seemed already tripped at the time of startup but not while the compressor motor was actually running. The tech did seem to think the motor was overheating but didn't specifically mention a thermal overload protector. I only learned about this from speaking to the manufacturer.

 

Just to be clear, the thermal overload is in the compressor and cuts out ONLY the compressor.

Most likely it did cut out when it was running and you probably just did not recognize that.
Could it cut out when the system is satisfied and shuts down, sure, but unlikely unless it was just about to happen anyways.

It could also happen on start up due to a number of factors.

As for you hearing it try, unless you are standing by the condenser when it does try to start, you will most likely not hear it try.
Depending on temperature of the compressor and ambient temperature, reset could be quite some time.

Repeated activations of this thermal overload is not goo for the life of the compressor or the overload itself. The overload is a last ditch effort to keep the compressor from failing, but the overload itself is NOT meant as an operational device, but a safety. If at some point it does not reset, it is new compressor time!!

Only numbers from the tech can allow us to make any kind of informed response to whether the issue has been resolved, if indeed that was the issue, or if you still have issues.

 

Also, oddly, and not sure if this means anything, but the temperature of the metal cabinet of the condenser unit with the issue is actually a few degrees cooler than the temperature of the cabinet of the unit without the issue. I would have expected the opposite if it’s the motor overheating. These are through the wall FristCo units which function like outdoor units but they’re both in a closet off the deck, mounted through the wall to the outside. I can’t aim my infrared temperature gun directly at the compressor motors without taking the back covers off the units and I’m not going to do that myself. I just found it interesting that the temperature of the metal cabinet of the unit with the issue is actually a few degrees cooler than the other unit.

 

Update: I had it at a lower than normal (for us) temperature and it ran continuously all afternoon long (around 5.5 hours) without anything shutting off the compressor motor the whole time. I determined (by standing in front of the condenser unit when the thermostat called for cooling) that whatever protective switch/relay is cutting off the power to the compressor is doing so at the time of start-up and not any time before that. I heard (and recorded on my phone) a gentle hum of the compressor motor trying to start up, and then a click and it stopped, and then the fan motor inside the condenser unit came on. Then a few minutes later I heard the compressor start up automatically on its own and stay on. Is this likely the thermal overload getting triggered at the time of start-up, and what could be causing it to happen? Could adding a time-delay before start-up (minimum of 10 minutes) be a way to prevent this from occurring? Would be nice if the tech could figure out the actual cause as to why it is still happening even after he reduced the refrigerant level.

 

Infra red are worthless.

 

Modern thermostats have an anti short cycle built into them, usually default is 5 minutes, that keeps the unit from trying to come on because someone is finger blasting the thermostat or some youngster is playing with it and turning it on and off rapidly. So a delay timer SHOULDN'T be needed.

As for start up, both the compressor and the fan motor SHOULD come on simultaneously.
Usually you can't hear the internal overload trip.

If this start up can be duplicated with consistency, then troubleshooting it can be done.

How about an actual model number and not just the mfr name.

 

Our 2 units are both the 24WMU-A by FirstCo. I suppose the fan inside the condenser unit MAY have started at the exact moment the compressor attempted to start but it may have taken a few seconds to get up to speed where I could hear it. When the compressor motor itself failed to start due to some protective switch/relay abruptly cutting off the power to it, there was a prominent click at that exact moment. Seems strange it only took a few minutes for it to suddenly start again successfully on its own.

Yes, our Honeywell thermostats have a 5 minute delay to protect from very short cycles. Do you know if this delay would also protect the compressor from short cycling in the event of a brief interruption in power like 30 seconds while the thermostat is already calling for cooling? In other words, can the thermostat sense if the electrical power fails during during the cycle and prevent the compressor from being restarted if the power comes back on in less than 5 minutes?

The reason I was asking about a time delay is that maybe a 10 or 15 minute delay would give the compressor more of a chance to cool off before restarting. I know it should not really be necessary to have such a long delay though.

 

Still waiting to hear back from tech. In the mean time I programmed the thermostat to only target 2 cycles per hour instead of 3 which is helping in mid 80s temps so far. Two cycles per hour tends to increase the off time between cycles off time toward 10 to 15 or more minutes, which is giving the compressor motor a chance to rest more between cycles, but under more extreme conditions I suppose the off time may be reduced if the thermostat algorithm doesn't think it's keeping up with the temperature setting. Would be nice if the tech could figure out why when it gets above 85 degrees, at a setting of 3 cycles per hour, the motor still acts like sometimes needs more off time or it may get stuck at start and go into overload, if I'm understanding correctly (see audio in previous message). This all started happening after he added more refrigerant but it's still happening (albeit less frequently) after he reduced it somewhat afterward.

 

“IF” everything is right all it needs is 5 minutes off time before starting again.

 

Might want to have tech evacuate the system and recharge to the specified weight of refrigerant just to eliminate the charge issue an also remove any non-condensibles. No guarantee of cure, but at least you are back to factory specs as to full charge and no air.

Are these thru wall units where the indoor and outdoor fans are on the same motor?

While he is at it, have him check the cap for an intermittent short or open. Heat related.

 

Thanks. These are thru wall units, but the indoor fans are completely separate and the indoor fans are the blower motors of the furnaces and the evaporator coils are above the furnances.

 

Last time I did ask him "how is the capacitor" and he said it was good but next time I'll ask if it's possible there's an intermittent issue with it. Last time he was putting water on the compressor to get it to cool off, and said it was overheating but I'm not clear yet as to whether he was aware it was overheating as a result of a failed start.

 

Find a different contractor!

 

How do I find the right contractor in Bergen County area, NJ ?

 

Tech was back today. All he really did was adjust refrigerant again. Didn't really adjust it much but I'm wondering if he reduced it slightly. While he was there it was still going into internal overload at start when it was off for like 7 minutes and he doesn't really have any idea as to why that unit is going into overload at start while the other unit (same model and size, FirstCo 24WMU-A) does not. At around 10 minutes of off time the one with the issue wasn't going into overload. The other unit cools better as well and the vent temps are at least a few degrees cooler with the other unit. Both zones are for half the same level of one floor condo.

It turns out that both units have a start assist device attached. See photo. The photo is of the start assist for the unit that is working fine. The tech had already closed the cover of the other unit and I wanted to confirm that both units had a start assist device. The manufacturer does say this in the installation manual - "Compressor start assist devices (capacitor and start potential relay) may be required for installations with long line length, unusually
high or low ambient operating conditions, thermostatic expansion valves or any other situation which can lead to slow off cycle pressure
equalization and excessive compressor starting problems."

Seems strange that they are saying the start assist is optional and they list have an TXV as one reason when the manual later clearly states the system was designed to have a TXV connected to the evaporator.

When I asked the tech if it was possible the start assist kit was failing his comment was "usually when that happens they're blown" .

The tech was talking about installing a 10 minute time delay but that's trying to manage the symptoms of the problem without diagnosing the exact cause. Currently I have the thermostat set for 2 cycles per hour instead of the default 3 cycles which mostly results in longer off times but that's also managing the symptoms.

It hasn't failed to start yet since he left, but I'm wondering why this unit isn't equal to the unit for the other zone which has no issue and better cooling. Considering getting 2nd opinion but wondering how difficult it will be to find someone who can properly diagnose this.

We're on the 3rd floor and he was talking about possibly inspecting/cleaning the condenser coil, but it would cost extra and he isn't sure that's the issue since they're both next to each other and one doesn't have any issue. It sucks being on the 3rd floor because nobody really wants to get on a ladder and inspect/clean the coil from the outside. The tech also seemed to think if the coil being dirty were really an issue that there would be excessive heat on the liquid line attached to the condenser unit.

Here's what the start kit looks like for one of the two units (this is the one with no issue):

 

Your txv could be a hard shut off type which would require a hard start kit and yes they can fail without anything visual

 

Is there a way the tech could test to see if the capacitor of the start kit is failing? I can’t tell the spec of the capacitor from the photo since the label is partially blocked. If it’s the start capacitor I just hope whomever I go with next to diagnose this will have the rightt one on hand.

 

If I was the tech and going by what you said ( both are the same )
I'd switch the two around and see if the problem follows the kit.

 

I'm pretty sure the capacitor is 145-175 microfarads and 330VAC 50/60hz And I'm pretty sure this model of capacitor came with a bleed resistor installed. I guess I'll have to insist a matching capacitor is used if whomever I wind up getting the 2nd opinion from doesn't have one on hand. I was thinking about buying a capacitor myself just to have one on hand in case a tech doesn't have the right one, but I shouldn't have to buy my own parts, and I don't know for a fact that the start capacitor is the issue. I'm a little hesitant to have a tech swap them, because the other unit has been working the way it should and I don't want it to go into overload.

BTW, I was given a name of a contractor from a friend to get 2nd opinion, and I called him up, and this guy kept asking me to send pictures of my units and he kept insisting they were window units until I finally sent him a pic that showed the suction and liquid line attached to the top of the unit. He then proceeded to tell me that because it says "'Test Pressure 450 high side 250 low side" on the label of the units, that my units take R22 and not R410a, even though I pointed out to him that further down on the labels it clearly states the units were factory charged with R410-a, and the installation instructions and information brochure clearly state the units use R410-a as well. He kept insisting that those pressures are wrong for r410-a and based on what he is sees, that I should get someone else to do the servicing on these units. I then said 'I can't believe this. You were recommended by ______ and you're telling me the manufacturer is a crazy manufacturer who mislabels their units.' He then asked if I know the phone number of the manufacturer and I mentioned it was on the label, and he said he would talk to the manufacturer and get back to me. Even if he does I'm not sure I'd want to go with him. LOL

Oh, and the tech who I've been using all this time said my motors were scroll compressors when I asked what type, but I'm pretty sure they are reciprocating compressors based on them being oval and what I found online regarding the model number. Not that it makes much difference, I suppose.

I'm going to ask around again for recommendations on someone who can properly diagnose this. I don't think it has been going into overload today, but I suspect the system is likely now slightly undercharged and, as mentioned previously I've got the thermostat set for 2 cycles per hour instead of 3 which tends to increase the off time between cycles.

 

He's nuts here's a new R410a roof top unit I just installed.
Look at the test pressures.
He's probably thinking of the mini splits which do require higher test pressures.
By the way " test pressure " is just that, the minimum pressure amount by the manufacturer.

 

Wondering why my units (24,000 BTU which I think means 2 tons each) would be fitted with a 145-175 microfarad start capacitor when the hard start kits that I've found online for "1 to 3 ton units" look like they have an 88 - 106 microfarad start capacitor. Here's what is says on my motor:

 

Those are generic start kits. One size fits all. I don’t use them! I only use start kits recommended by the compressor manufacture!

 

Manufacturer says they recommend either the Kickstart T0-5 or Supco MPR5. I notice both have even bigger capacitors, and the labels seem to indicate 189-227 microfarads, but I don't know if that's because those have a "2 wire" design.

 

Your dealing with an obsolete compressor!
Do you have a bleed or non bleed TXV?

 

How does one determine that for certain?

 

Your service provider!

 

Keep looking!

 

I have to pay you to travel to my area if this keeps up.

 

Mount of town calls are 6 weeks out.