[whited44]

If you have three compressors you need 3 relays.

The fan function was not changed only the compressor function.

If either fan fails to activate, the compressor will eventually overheat tripping the circuit breaker. Adding the external relays will do nothing to address this issue.

Let’s determine why the fan is not turning.
It could be a faulty capacitor for the fan.
It could be a failed circuit or connector on the circuit board.
It could be a failed fan motor.
It could be a faulty thermostat.

Is it the indoor or outdoor fan that is not working?
Do you have the SCS manual, excellent trouble shooting steps in the manual.
Are you comfortable working with live 120V?
Will your multimeter test capacitors?

Oh Richard..  I love your questions. They always involve a meter.  I loathe the meter. My dad was always the electric guy and he would just tell me what to do.  He’s too old now and it’s forcing me to learn how to use it.  

The living room unit (outside rear) will run for a while.  Cool, inside and outside fan running.  But after about 1-2 hours the fans (both) will shut off however the compressor stays running

The bedroom unit (outside front) has 2 breakers. When I flip on the breaker 1 nothing happens, when I flip breaker 2 I can hear the compressor run, however no inside or outside fan.

How do I test the capacitors??
What shall I look for on the board??
I “think” The thermostat is ok
I do have the SCS manuals
I have a pretty nice meter but I don’t know where to run the knob to ?

[Richard]

There is a test function on some meters that allow you read a capacitor. Post a pic of the dial on your meter, and we will be able to tell right away.

You are looking for burn marks on the front and back of the board.

We need to test the thermostat to see what is going on. In God we trust, everybody else bring data.

You really can spend a lot of time, blood, and money throwing parts at this but, diagnosis is far easier and quicker. Look at it this way. This is an opportunity to learn some basics about electricitry, and how to use a voltmeter. This learning will make ownership of this coach and future coaches much easier.

You have demonstrated through your actions and solutions that you are an intelligent and energetic person willing to do the work. Let us help you through this process.

I am going to start with Chapter 1. The tstat is 12V powered. Depending upon what you set the tstat on, it will put out 12V signals that pass to the circuit board on the SCS. Those signals are on separate wires. It can put out a low indoor fan, high indoor fan, compressor one, compressor two, and aquahot heat.

So when you put the tstat on fan only, a 12V signal will pass to the circuit board to turn on the indoor fan. When you turn on Cooling low, the tstat will send signals down the low fan and comp 1 wires. When you activate Cooling High, the tstat sends signals down the high indoor fan, compressor 1, and compressor 2 wires.

Wait…………..so what activates the outdoor fan? The outdoor fan is activated when the compressor circuit is activated by a relay on the control board. If both compressors are activated then the outdoor fans runs on high.

Interesting tidbit. Although the tstat has low and high indoor fan settings, and the board has indoor low and high circuits, and the indoor fan motor has low and high wires, I could NEVER tell a speed difference.

So why belabor all these points? The behavior of indoor and outdoor fans stop but compressor continues to run makes no sense to me. If the compressor is getting power the outdoor fan should be getting power. Both indoor and outdoor fans stopping at the same time does not compute because they are on two independent circuits.

[Richard]

Do the following easy diagnostics.

Run the front unit on low cool.
What is the amperage reading on the amp meter at the driver console.
What is the air discharge temp measured with digital thermometer. Cool is not a number I can use to help you.
Let it run for the two hour period you mention.
Did the fans shutdown?
If they did, what is the amperage now?

Now, and this can be a different day.
Run the same test with HIGH cool.
Record the amperage. You should have amperage on BOTH legs now.
What is the air discharge temp?
Does it shut down again after a couple of hours.
If it did what are the amperage readings now?

I know this is slow and laborious, but you are describing a problem that is not evident given the description. It may be a simple fix, and it could be tricky to diagnose. Let’s get the data to help.

[whited44]

There is a test function on some meters that allow you read a capacitor. Post a pic of the dial on your meter, and we will be able to tell right away.

You are looking for burn marks on the front and back of the board.

We need to test the thermostat to see what is going on. In God we trust, everybody else bring data.

You really can spend a lot of time, blood, and money throwing parts at this but, diagnosis is far easier and quicker. Look at it this way. This is an opportunity to learn some basics about electricitry, and how to use a voltmeter. This learning will make ownership of this coach and future coaches much easier.

You have demonstrated through your actions and solutions that you are an intelligent and energetic person willing to do the work. Let us help you through this process.

I am going to start with Chapter 1. The tstat is 12V powered. Depending upon what you set the tstat on, it will put out 12V signals that pass to the circuit board on the SCS. Those signals are on separate wires. It can put out a low indoor fan, high indoor fan, compressor one, compressor two, and aquahot heat.

So when you put the tstat on fan only, a 12V signal will pass to the circuit board to turn on the indoor fan. When you turn on Cooling low, the tstat will send signals down the low fan and comp 1 wires. When you activate Cooling High, the tstat sends signals down the high indoor fan, compressor 1, and compressor 2 wires.

Wait…………..so what activates the outdoor fan? The outdoor fan is activated when the compressor circuit is activated by a relay on the control board. If both compressors are activated then the outdoor fans runs on high.

Interesting tidbit. Although the tstat has low and high indoor fan settings, and the board has indoor low and high circuits, and the indoor fan motor has low and high wires, I could NEVER tell a speed difference.

So why belabor all these points? The behavior of indoor and outdoor fans stop but compressor continues to run makes no sense to me. If the compressor is getting power the outdoor fan should be getting power. Both indoor and outdoor fans stopping at the same time does not compute because they are on two independent circuits.

Thanks for the detailed reply. I’ve attached a pic of the meter and of some other stuff..  I’m just razzin ya about the meter thing. I do want to learn and I want to make my life with this thing as easy as possible to troubleshooting is definitely the move over throwing parts at it.

I didn’t have a whole lot of time to mess with it today.  I did turn the “fan” on the thermostat for the living room unit.  It only ran for about 30 minutes and quit.  It was buzzing like it was trying to run but I shoot it off so I didn’t burn it up.  This unit I think is the single compressor unit it’s significantly smaller than the other unit.  

I’ll have time to run more tests tomorrow that you spoke about earlier and report back

[hypoxia]

You are getting excellent advice on troubleshooting your problem.  As Richard suggests, do yourself a huge favor and acquire a decent meter that checks capacitance, that would be my first immediate step.  You may have more than one failure point.

My experience in general FWIW, regarding A/C parts causing failures. I have changed a couple hundred condenser fan capacitors, a few dozen condenser fans, a dozen or two thermostats with the relatively small group of units maintained over the last 30 years.  On a normal R22/R410 household A/C unit, if the condenser fan quits the compressor internal thermal switch will overheat and shut the compressor off in a matter of seconds.  If the condenser fan shaft sleeve/bearing is bad or needing lubrication the fan will lose RPM, most are 825 or 1075RPM, raising the compressor temperature etc., etc..  I have seen the evaporator turn into a block of ice that took all day to melt on a 115ºF day due to a dirty condenser.  A capacitor has a 5% tolerance, anything outside of that range can cause a variety of problems with the fan motor, intermittent or not running at all.  The motor capacitor needed is specified on the tag attached to the motor.  There is always the possibility someone installed an incorrect size capacitor, check the tag.  Most old A/C units were made for the cheapest air filters with good airflow.  Do not use the HEPA or pleated filters designed to clean your air, they restrict airflow causing the fan to work harder causing the compressor to run warmer causing the pressures to be higher causing the refrigerant system to be inefficient and eventually causing the evaporator to become a block of ice.    Newer systems were made for those filters.

This week I will be checking all A/C units capacitors, motors etc..  Most techs do an amp check on the fan motor, I use a screwdriver to spin the condenser fan.  If it doesn't keep spinning freely I replace the motor.  I try to avoid having those phone calls at 3PM on a 118º day.

Most problems are within your capability, keep at it!

[whited44]

You are getting excellent advice on troubleshooting your problem.  As Richard suggests, do yourself a huge favor and acquire a decent meter that checks capacitance, that would be my first immediate step.  You may have more than one failure point.

My experience in general FWIW, regarding A/C parts causing failures. I have changed a couple hundred condenser fan capacitors, a few dozen condenser fans, a dozen or two thermostats with the relatively small group of units maintained over the last 30 years.  On a normal R22/R410 household A/C unit, if the condenser fan quits the compressor internal thermal switch will overheat and shut the compressor off in a matter of seconds.  If the condenser fan shaft sleeve/bearing is bad or needing lubrication the fan will lose RPM, most are 825 or 1075RPM, raising the compressor temperature etc., etc..  I have seen the evaporator turn into a block of ice that took all day to melt on a 115ºF day due to a dirty condenser.  A capacitor has a 5% tolerance, anything outside of that range can cause a variety of problems with the fan motor, intermittent or not running at all.  The motor capacitor needed is specified on the tag attached to the motor.  There is always the possibility someone installed an incorrect size capacitor, check the tag.  Most old A/C units were made for the cheapest air filters with good airflow.  Do not use the HEPA or pleated filters designed to clean your air, they restrict airflow causing the fan to work harder causing the compressor to run warmer causing the pressures to be higher causing the refrigerant system to be inefficient and eventually causing the evaporator to become a block of ice.    Newer systems were made for those filters.

This week I will be checking all A/C units capacitors, motors etc..  Most techs do an amp check on the fan motor, I use a screwdriver to spin the condenser fan.  If it doesn't keep spinning freely I replace the motor.  I try to avoid having those phone calls at 3PM on a 118º day.

Most problems are within your capability, keep at it!

From what I understand the only filters are under the entry steps??  Or are there some elsewhere??

[[email protected]]

You are getting excellent advice on troubleshooting your problem.  As Richard suggests, do yourself a huge favor and acquire a decent meter that checks capacitance, that would be my first immediate step.  You may have more than one failure point.

My experience in general FWIW, regarding A/C parts causing failures. I have changed a couple hundred condenser fan capacitors, a few dozen condenser fans, a dozen or two thermostats with the relatively small group of units maintained over the last 30 years.  On a normal R22/R410 household A/C unit, if the condenser fan quits the compressor internal thermal switch will overheat and shut the compressor off in a matter of seconds.  If the condenser fan shaft sleeve/bearing is bad or needing lubrication the fan will lose RPM, most are 825 or 1075RPM, raising the compressor temperature etc., etc..  I have seen the evaporator turn into a block of ice that took all day to melt on a 115ºF day due to a dirty condenser.  A capacitor has a 5% tolerance, anything outside of that range can cause a variety of problems with the fan motor, intermittent or not running at all.  The motor capacitor needed is specified on the tag attached to the motor.  There is always the possibility someone installed an incorrect size capacitor, check the tag.  Most old A/C units were made for the cheapest air filters with good airflow.  Do not use the HEPA or pleated filters designed to clean your air, they restrict airflow causing the fan to work harder causing the compressor to run warmer causing the pressures to be higher causing the refrigerant system to be inefficient and eventually causing the evaporator to become a block of ice.    Newer systems were made for those filters.

This week I will be checking all A/C units capacitors, motors etc..  Most techs do an amp check on the fan motor, I use a screwdriver to spin the condenser fan.  If it doesn't keep spinning freely I replace the motor.  I try to avoid having those phone calls at 3PM on a 118º day.

Most problems are within your capability, keep at it!

From what I understand the only filters are under the entry steps??  Or are there some elsewhere??

Mine are under the stairs. Only way to get to my coils on the units to clean them is to pull the unit. Suspect its the same for yours. Mine were actually not that dirty, I was surprised especially since there was dust almost in all the bays from being taken out west, there was even sediment in the water filter I had to clean out.

[whited44]

Do the following easy diagnostics.

Run the front unit on low cool.
What is the amperage reading on the amp meter at the driver console.
What is the air discharge temp measured with digital thermometer. Cool is not a number I can use to help you.
Let it run for the two hour period you mention.
Did the fans shutdown?
If they did, what is the amperage now?

Now, and this can be a different day.
Run the same test with HIGH cool.
Record the amperage. You should have amperage on BOTH legs now.
What is the air discharge temp?
Does it shut down again after a couple of hours.
If it did what are the amperage readings now? 

I know this is slow and laborious, but you are describing a problem that is not evident given the description. It may be a simple fix, and it could be tricky to diagnose. Let’s get the data to help.

Ok so I performed the first test
Set the living room unit on low cool..  

These were the readings at the thermostat, a thermostat placed where the air comes out, the control panel, and inverter readout

I’m going to put the after it ran for a while notes in the next post I can’t put the pictures in all fancy like you guys do

---

This is after it ran for a while. Things are cooling and it’s going good

Until after it ran for over an hour the fans would kind of surge ad about every 10 seconds the AC amps would spike to 60 for about 1 second. I put it on high cool and it did the sale thing for about 10 more minutes and then the whole thing quit running. 

I do kind of suspect the compressor quit running because it wasn’t draining underneath the condensation out. It wasn’t terribly humid here today tho.

[Richard]

You said the fans were surging. Did they stop as you had said previously?
Does your front unit have one or two compressors?
When it pulls the 50+ amps, the rotor is locked on the compressor, the thermal protector located on the compressor is breaking the circuit and when the thermal cools off it is resetting automatically and the compressor is trying to start again.

Here is what is puzzling to me. Normally when you get a locked rotor situation. It is locked from the gitgo.
I typically associate the compressor locking up after a period with high head pressures associated with either of the fans stopping.

But ………there is one more scenario that could explain this. If the unit is low on refrigerant, the evap coil will operate below 32 degrees which will eventually cause water to freeze and block the air flow.

I think the unit is low on refrigerant. Unless someone has added taps you will not be able to simply put gauges on it and test.

After it misbehaves like this does it drip water for hours? Just my opinion.

[whited44]

You said the fans were surging. Did they stop as you had said previously?
Does your front unit have one or two compressors?
When it pulls the 50+ amps, the rotor is locked on the compressor, the thermal protector located on the compressor is breaking the circuit and when the thermal cools off it is resetting automatically and the compressor is trying to start again.

Here is what is puzzling to me. Normally when you get a locked rotor situation. It is locked from the gitgo.
I typically associate the compressor locking up after a period with high head pressures associated with either of the fans stopping.

But ………there is one more scenario that could explain this. If the unit is low on refrigerant, the evap coil will operate below 32 degrees which will eventually cause water to freeze and block the air flow.

I think the unit is low on refrigerant. Unless someone has added taps you will not be able to simply put gauges on it and test.

After it misbehaves like this does it drip water for hours?  Just my opinion.

The fans and the whole thing ended up quitting. I can hear a buzzing sound down thru the entry stairs but it won’t restart until tomorrow. 

The front unit has one compressor

I can tell I think anyway when it starts that 50 amp pull that it’s no longer cooling like it was prior to this when it starts happening. 

It is not wet underneath the unit