AC PROBLEMS! I have tied a rope and trying to hangon.

tru2au · 05-09-2016, 12:34 AM

Though, I am almost to the point of giving up. Here is the issue and I have spent numerous hours searching for a solution to no avail. The unit is setting outside. My nephew replaced the capacitor and starter and the unit has been thoroughly cleaned. The condenser is ice cold and the air is very cool. I have plugged it up and ran it for 4 solid hours with the unit cooling good. It never cut off because it didn't get below the setting on the thermostat. I ran it on low and it worked fine. Though, when I cut the switch off and cut it back on. The unit strained to start back up the compressor and it tripped the breaker. Also, if I let the unit stay off for a few minutes and start it back up it works good. It runs perfect until the thermostat cuts it off and then restarts it. That is when the breaker is tripping. Will installing a larger capacitor or install a Hart Start Kit would that help any? Can I just remove the thermostat and run it non stop till I turn it off or is there something else that can fix it? Here is the model name and #. Coleman Mach 8335B676. It is a 15,000 BTU unit and came off another popup. I was going to install it on my popup but don't want to do that and it tear up like it's trying to do now. This belonged to my nephew but he has money so he just went out and purchased a new unit. I am trying to get this running to use in my popup. If anyone could give me any kind of answers or assistance I would greatly appreciate it. Thanks and have a "Blessed Day". Chris

trbomax · 05-09-2016, 12:46 AM

Well,the CONDENSER should be very warm and the EVAPORATER very cold.When you cut it off and then right back on,there wasnot enough time for the "high side" comming off the compressor,to dissapate thru the expansion valve and then thru the evaporater coils.Net result is that you were trying to start a compresser that had a high head pressure instead of equal pressure on both the suction and discharge sides.It is what they call "lockedor locked rotor".When you wait a few minutes, the charge equalizes and the unit starts normally.Thats how its supposed to work.

bob dirt · 05-09-2016, 12:55 AM

Quote:

Originally Posted by trbomax

Well,the CONDENSER should be very warm and the EVAPORATER very cold.When you cut it off and then right back on,there wasnot enough time for the "high side" comming off the compressor,to dissapate thru the expansion valve and then thru the evaporater coils.Net result is that you were trying to start a compresser that had a high head pressure instead of equal pressure on both the suction and discharge sides.It is what they call "lockedor locked rotor".When you wait a few minutes, the charge equalizes and the unit starts normally.Thats how its supposed to work.

....and you may need a hard start kit to help the compressor. Do not install a run capacitor on the compressor larger than what it is rated for. Also, don't turn it off and then right back on anymore. Your compressor will get tired of you doing that and will leave you stranded

tru2au · 05-09-2016, 01:17 AM

Probably some of the best info I have got. I understand about the turning on and off with no delay could be a problem. I just can't figure out why it does it again when the thermostat kicks it back on when it shuts down after reaching the temperature you have it set on when you started it. Now that is my biggest problem. Since we are going on a family camping trip in about three weeks I don't want to have to deal with resetting the breaker 10 times a day. Oh, as far as the Hard Start Kit. Will this one work? Test Listing Luxaire York Coleman Compressor Hard Start Capacitor 024 20867 002 | eBay

If not what do you recommend? Thanks again for your assistance.

Toddupton · 05-09-2016, 05:45 AM

One question. How long is the unit off before the thermostat call for it again. The stat should have a delay in it so it will not come back on within 5 minutes or so.

ScottBrownstein · 05-09-2016, 05:55 AM

From what I can tell your unit is running normally. Most thermostats will wait at least 2 minutes before a restart. You indicated that when you waited before turning it on with no thermostat all was well. What remaining problem are you trying to solve?

fonzie · 05-09-2016, 06:10 AM

I think if you are running it outside in the open air (on a test bench) the thermostat can not sense the temperature properly if it is part of the AC, it needs to be installed and run in an enclosed place.....

TURBS · 05-09-2016, 06:39 AM

A few questions
What is the breaker size?
Did your camper come equipped with an a/c?

2008 2500hd Duramax
2015 Columbus 320RS
2016 nights camped "5"
2015 nights camped "34"

bob dirt · 05-09-2016, 08:13 AM

Quote:

Originally Posted by tru2au

Probably some of the best info I have got. I understand about the turning on and off with no delay could be a problem. I just can't figure out why it does it again when the thermostat kicks it back on when it shuts down after reaching the temperature you have it set on when you started it. Now that is my biggest problem. Since we are going on a family camping trip in about three weeks I don't want to have to deal with resetting the breaker 10 times a day. Oh, as far as the Hard Start Kit. Will this one work? Test Listing Luxaire York Coleman Compressor Hard Start Capacitor 024 20867 002 | eBay

If not what do you recommend? Thanks again for your assistance.

Not sure about THAT hard start kit. There are threads here with peeps installing them and working great. My expertise is on larger units residential and commercial.
Another thing you might want to check is the high voltage wiring connections at the breaker, breaker panel, and the hook up at your a/c unit. They need to be snug. Don't wrench too hard on the breaker lugs.

AquaMan · 05-09-2016, 08:24 AM

Quote:

Originally Posted by TURBS

A few questions
What is the breaker size?
Did your camper come equipped with an a/c?

2008 2500hd Duramax
2015 Columbus 320RS
2016 nights camped "5"
2015 nights camped "34"

X2 Also check voltage, the lower the voltage the higher the amp draw.

Danesville · 05-09-2016, 11:54 AM

You could install a delay on make timer to allow the unit time to equalize

Tom48 · 05-09-2016, 12:00 PM

Quote:

Originally Posted by AquaMan

X2 Also check voltage, the lower the voltage the higher the amp draw.

If you are saying that the unit is outside, as opposed to being within the defined cool air space of the RV, that is likely the problem. If you are installed in RV, is it a factory install or after market, where someone put the thermostat too close to the cold air coming out so that it shuts down while the room is still hot thus in a minute the thermostat is hot again and cycling on????

Or if it is a new thermostat in a correct location, some have a setting of the thermostat on off temp diff and it can be set to close. Ie come on at 75, shuts off at 74. Then in a minute it trys to come back on and hits lock as has been described.

DynaQuestDave · 05-09-2016, 12:19 PM

So assuming you understand the basic concept of how an a/c system works, after the compressor is actually running for a few minutes it's load is quite high created by conversion of low pressure vapor or gas on the suction side coming from the evaporator to discharging the refrigerant as high pressure gas to the condenser. The hermetic compressor does not like liquid at the suction side because liquid cannot be compressed and the compressor motor can't be started while discharge pressure is high because on startup the motor cannot produce enough torque to overcome the high pressure load. Either of these conditions will prevent starting. Then assuming the system is not overcharged which is a cause of liquid returning to the suction side of the compressor and that the compressor has been turned off long enough for suction and discharge pressures to equalize by either manually delaying re-start or thermostat delay it should reliably start unless the hermetic compressor motor is failing or there is something wrong with the supply power. If supplied voltage is too low the current will rise disproportionally and dump a good circuit breaker. If the compressor motor is failing it may draw too much starting current even after system pressures equalize causing the breaker to trip. If neither of these conditions are the culprit I would suggest finding an exact replacement for the circuit breaker and replacing it because these do go bad.

mike.t · 05-09-2016, 12:34 PM

Well all these answers show just how smart some of the Forest River Forum members are. Very well done.

tru2au · 05-09-2016, 10:19 PM

Does these units have a replaceable delay switch or can one be installed? I have made this a lot more complicated than it should be. This is the whole problem. The unit runs fine when you turn it on but when it gets to the temperature it shuts off. When it tries to restart that is when it pulls so many amps that it trips the breaker. The thermostat does not stay off for 5 minutes that is for sure. I should have used common sense on turning the unit on and off quickly.

Bluepill · 05-09-2016, 10:48 PM

Lots of delay timers are available. This should work if your thermostat operates on 24 volts AC

Amazon.com: Packard PTD102 Delay on Make Timer Relay: Automotive

Before you decide on a delay timer, make sure that you do not have the circuit breaker trip problem if you turn off the power for five minutes and then re-connect the power.

ScottBrownstein · 05-10-2016, 07:02 AM

Quote:

Originally Posted by Bluepill

Lots of delay timers are available. This should work if your thermostat operates on 24 volts AC

Amazon.com: Packard PTD102 Delay on Make Timer Relay: Automotive

Before you decide on a delay timer, make sure that you do not have the circuit breaker trip problem if you turn off the power for five minutes and then re-connect the power.

Been through this with my stick house. I think what he really needs is a "delay on break" timer, which is generally used to protect AC compressors from short cycling. It will not re-energize for the pre-set time once the compressor is shut off but will add nothing if it has been off for the prescribed time. "delay on make" relays will always wait the set time once power has been applied and are used to stage multiple loads to avoid them starting simultaneously.

In my case, even though the thermostat had a time delay, if you cycle the power it often won't help.

They look the same and cost the same and are often confused...I think!

tru2au · 05-11-2016, 06:11 PM

Quote:

Originally Posted by Tom48

If you are saying that the unit is outside, as opposed to being within the defined cool air space of the RV, that is likely the problem. If you are installed in RV, is it a factory install or after market, where someone put the thermostat too close to the cold air coming out so that it shuts down while the room is still hot thus in a minute the thermostat is hot again and cycling on????

Or if it is a new thermostat in a correct location, some have a setting of the thermostat on off temp diff and it can be set to close. Ie come on at 75, shuts off at 74. Then in a minute it trys to come back on and hits lock as has been described.

The unit is sitting outside and turned on at night when the temperature is below 70. This was installed on my nephews camper and did the exact same thing. He has $1's but just not any cents. lol It didn't even try to figure it out after the voltage meter was reading correctly on everything. He just went out and spent $600 for a new one. The unit was factory installed on his popup. I have determined from other peoples responses. To NOT turn it off and back on quickly. Give it a few minutes. Though, like I have originally posted. It's not the capacitor, ground, starter or breaker. My nephew is a Electrician and said everything as far as wattage was reading correctly when it was running or when it tried to start back up after the temperature went above what the temp was set at. The unit when it is working is ice cold. So, I don't really think it's the compressor but have no idea what it could be. Thanks

**Flybob** · 05-11-2016, 06:18 PM

If you need to increase the delay between shutting off and back on, you can replace the thermostat with one that has adjustable hysteresis.

tru2au · 05-11-2016, 06:21 PM

Quote:

Originally Posted by ScottBrownstein

Been through this with my stick house. I think what he really needs is a "delay on break" timer, which is generally used to protect AC compressors from short cycling. It will not re-energize for the pre-set time once the compressor is shut off but will add nothing if it has been off for the prescribed time. "delay on make" relays will always wait the set time once power has been applied and are used to stage multiple loads to avoid them starting simultaneously.

In my case, even though the thermostat had a time delay, if you cycle the power it often won't help.

They look the same and cost the same and are often confused...I think!

You say it needs a "delay on break" timer. Where can I purchase one of these? Are they universal or do I have to purchase one that fits my particular unit? Also, you mention "delay on make" relays. Does that mean I can set the relay for like 5 minutes or longer before it comes back on? My problem is not the unit not coming on and running. It's just when it gets to the temperature that is set and cuts off that is causing the problem. It starts back up in like two minutes and strains to get the compressor started back up. That's when it kicks the breaker. Thanks

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