Red Dot AC - Troubleshooting

[dac9901]

I've installed the Red Dot AC kit ([FONT=&quot]RD-2-4233-OP)[/FONT] in my m998 recently and the air coming out of the vents is not as cold as I would expect.

4 lbs of freon was loaded after using the vacuum pump and ensuring no leaks as evident by watching the ac manifold gauge set. The coldest the AC I've recorded coming out of the vents is around 60 using a meat thermometer. I get around 48 degrees in my personal car.

Questions for all you experts:
1) My Condenser fans turn on when high pressure hits around 270 and cycle back off after running for about 6 seconds. When the fans are running the air seems colder. How often does your Condenser fans run (all the time, cycle on and off)?? I was thinking of running power to the condenser fans to a switch that I can keep the Condenser fans on all the time when it's super hot outside. Thoughts?

2) The instructions stated the new compressor has oil already supplied so I did not add any additional oil when adding freon. Even a mechanic I showed the install instructions seemed to think the compressor already had oil. Anyone else think differently?

Thanks in advance!

 

[juanprado]

Could you scan and post the instructions and material packing list?

I am going down this road soon but I am piecing my kit together as I have most of the components.

Most units require a few ounces more for drier & condenser than oe filled compressor. Instructions should gave stated total system capacity.

My only other thought is do you have enough r134? Gauge pressure on low and high side will guide you on this based on outside temp?

 

[dac9901]

The instructions and packing list are listed on this thread - https://www.steelsoldiers.com/showthread.php?157446-HMMWV-Red-Dot-A-C-Install-Instructions

My mechanic said freon level is good and compressor is running full time. He said the condenser fans should run all the time - not cycle on and off. He admitted he was not sure how the Red Dot system should work so the condenser cycle on and off may not be abnormal. I'm going to run 24v directly to condenser fans and see if this makes a temperature difference forcing them to run full time. The condenser relay is internal to the Evaporator and not easy to access.

 

[Action]

I know nothing of the reddot, but the factory a/c condensor fans run all the time when the a/c system is running.

 

[dac9901]

Red Dot Corp. did respond back to my email inquiry about the compressor. The compressor does have the appropriate amount of oil already in the compressor so there is no need to add any additional oil for a new system, just freon.

I did a test and when the condenser fans are wired to run 100% of the time (direct connect to battery) the air is much colder. A

ANY ONE OUT THERE WITH A RED DOT KIT INSTALLED ON THEIR HMMWV? IF SO, DOES YOUR CONDENSER RUN 100% OF THE TIME OR CYCLE ON/OFF??

Thanks again.

 

[M35A2-AZ]

I have the Red dot system installed on a M923A1 and the condenser fans turn on and off.

 

[kcobean]

I don't want to derail your thread, but can you tell me where to purchase the Red Dot kit and approximate cost?

 

[dac9901]

@kcobean - I purchased my Red Dot system on GovLiquidations site and they are also for sale on eBay. They can run $1000 and up for a complete set. It takes quite a bit of time to install...

@M35A2-AZ - what temperature comes out of your vents? The coldest I'm getting is around 60 degrees. Do your fans run for more than 5-6 seconds before turning off? I'm trying to identify if my system is operating normal or if something is amiss. Thanks!

 

[M35A2-AZ]

@M35A2-AZ - what temperature comes out of your vents? The coldest I'm getting is around 60 degrees. Do your fans run for more than 5-6 seconds before turning off? I'm trying to identify if my system is operating normal or if something is amiss. Thanks!

dac9901, I see 37 degrees sometime, most around 40 degrees. My fans run about 5-6 seconds then off for 25 or so.

 

[av8or]

I have a red dot in my m916 camper. Works well, fans are on and off with more off time than on. A little more freon than the 4 lbs recommended. It will freeze you out if left on high even the desert SW.

 

[dac9901]

Thanks for the responses, I'm going to evacuate the system and have it done again to see if the temp improves.

 

[M35A2-AZ]

You said when your fans turn on the high side was 270, what does the low side read. On my three systems the low side runs around 30-40psi.

 

[dac9901]

Fans Off:
Low Pressure 58, High 295

Fans On:
Low Pressure drops to 35, High Pressure drops to 200

Thoughts?

 

[M35A2-AZ]

I'm not a a/c guy, but the high side looks a little low with the fans on.

 

[kzeyus]

I've finally got my Red Dot A/C installed and have a question about the amount of R134 needed. We've added 6 lbs of r134 and temp output is around 60. Started with the recommended 4 lbs, siteglass showed bubbles and foam and gauges showed system low on r134 so mechanic added a little at a time till we're up to 6 lbs. Works much better with 6 lbs, cooler than it was at 4 lbs by 20 degrees or so, gauges don't show as much fluctuation. Site glass still shows bubbles and even a little foam for a while after condenser fans kick off, but much less time that it did when only 4 lbs in system, so don't think the 6 lbs is too much, but not sure how much more can be safely added. Mechanic was afraid to add much more for fear of blowing compressor. It seemed to improve with every half pound we added, just don't want to go too far, but would like it to put out colder air. Mechanic knows A/C on modern passenger cars (cert toyota mechanic) but this system took so much more r134 than a modern car that I think it made him a little nervous. We decided to run it a few days and see how it goes, and ask around a bit.

The unit was the model for o'gara-hess add on armor (Rd-2-4234-0), supposed to mount between antenna towers just behind rear partition/seats. I picked up slantback style mounts for the condenser and mounted on top rear of the helmet top, and switched to a v-belt compressor (still same style red-dot sanden compressor). Had to buy new hose to reach condenser where it's mounted, I figure there is 15-20 feet more hose than the original kit contained. Not sure how much extra r134 would be needed with 20 more foot of hose.

Anyone with experience in these kits have input on how much refrigerant the system can/should hold? Can we go by bubbles in sight glass to add more r134? Better way to test? - know temps can be measured and compared, but not clear on where/how. Mechanic says usually has a chart for a vehicle with high/low pressure ranges at ambient temps to work by.

Thanks

 

[juanprado]

I've finally got my Red Dot A/C installed and have a question about the amount of R134 needed. We've added 6 lbs of r134 and temp output is around 60. Started with the recommended 4 lbs, siteglass showed bubbles and foam and gauges showed system low on r134 so mechanic added a little at a time till we're up to 6 lbs. Works much better with 6 lbs, cooler than it was at 4 lbs by 20 degrees or so, gauges don't show as much fluctuation. Site glass still shows bubbles and even a little foam for a while after condenser fans kick off, but much less time that it did when only 4 lbs in system, so don't think the 6 lbs is too much, but not sure how much more can be safely added. Mechanic was afraid to add much more for fear of blowing compressor. It seemed to improve with every half pound we added, just don't want to go too far, but would like it to put out colder air. Mechanic knows A/C on modern passenger cars (cert toyota mechanic) but this system took so much more r134 than a modern car that I think it made him a little nervous. We decided to run it a few days and see how it goes, and ask around a bit.

The unit was the model for o'gara-hess add on armor (Rd-2-4234-0), supposed to mount between antenna towers just behind rear partition/seats. I picked up slantback style mounts for the condenser and mounted on top rear of the helmet top, and switched to a v-belt compressor (still same style red-dot sanden compressor). Had to buy new hose to reach condenser where it's mounted, I figure there is 15-20 feet more hose than the original kit contained. Not sure how much extra r134 would be needed with 20 more foot of hose.

Anyone with experience in these kits have input on how much refrigerant the system can/should hold? Can we go by bubbles in sight glass to add more r134? Better way to test? - know temps can be measured and compared, but not clear on where/how. Mechanic says usually has a chart for a vehicle with high/low pressure ranges at ambient temps to work by.

Thanks

View attachment 730166View attachment 730167

20 ft of hose can increase the amount of r134. Are you using an ac manifold gauge set with high and low hoses? You can monitor high side readings with temp charts if you see any increase in pressure but it sounds like you need more refrigerant.

 

[Bigfan]

Have red dot unit. What would cause high blower to stop working, low and medium ac work fine, high nothing happens

 

[simp5782]

Have red dot unit. What would cause high blower to stop working, low and medium ac work fine, high nothing happens

Resistor or dead connection in the motor

 

[Bigfan]

Where is resistor located? Any idea where to buy a new one?

 

[simp5782]

Should be in the blower box. It will be somewhere between the switch and the blower unit. On my MCC unit it is screwed to the blower unit.

You need to do proper diagnostics before going that far though. Take your test light and check to see if you have power to the blower motor on high, if yes, replace blower motor, if no remove the main fan switch and check for power out of the switch on the high, if no power but there is power to the switch replace the switch, if yes then check continuity of the wire from switch to blower motor. if it's good locate the resistor and check for power to it and coming out of it on high. If the continuity is bad then you more than likely have a resistor in line as it is open and dropping power .