1M system no start

[Neil Calvert]

"I just completed installation of a new DIY 1M system. I followed all instructions to the letter. The leak test was perfect. I retested again after installation in the boat. Everything is fine and I am down to the last 2 pages of the instructions -- Charging. Instruction #4 - "... The fan should come on and a few seconds later the compressor should start." That is not exactly how my system works -- the compressor starts first, then the fan comes on. However, it did start and everything seemed fine. I continued thru step #8 and again all is fine. After about 2 hours the system turned off. I continued to monitor during this time. The suction pressure towards the end was about 6 psi. So good so far.Now the problem. About a half hour after it shut down, I wanted to see how cold it the box could get. So I turned the t'stat full up. The compressor started then shut down. A few seconds later it started again, ran about 10 seconds and shut down again. After 1 minute it tried to start again and shut down. About the third minute it tried again and this time it continued to run and again worked normally. I had left the blue hose connected during this time and monitored what was happening. The pressure (while running) remained about 5+ psi.I let it run about an hour and it turned off again. I considered this a normal shutdown as the box got noticeably colder. At this point I turned the system off at the breaker as it was late and I did not want to risk a repeat as mentioned above while we slept. That was yesterday. This morning when I got up, I turned the system ON and it would not start. It cycled on for 4 to 8 seconds at 1 minute intervals. During this time I could see the suction pressure come down 5 to 10 pounds before it shut down. This indicates to me that the compressor is not the problem. Do I have a bad controller (out of the box) or some other problem?Help, please.Neil CalvertHylas 44, "La Boheme""

[Neil Calvert]

"Dear Forum Tech Guy:I am not sure if you received the previous post but have not had a reply, so thought I would try again. I have a knowledgeable friend who has offered some coaching but he is not THAT knowledgeable so I am deferring back to you. I bled off all the refrigerant (R-134a) and re-pumped the system down like new. I heated the system up to 75*+ while doing this for 3 hours. I then re-introduced R-134a vapor into the system per the "Charging Instructions", step #3, page 32. I turned the system ON and it started as I described previously -- it attempted to start then shot down - twice. On the 3rd minute/attempt it started and continued to run. I began adding refrigerant per instructions and the system continued to run for about 20 minutes, then shut down. This time it started to get cold but no frost on the evaporator. Also I left the red line attached and was able to see compressor pressure, steady at about 60 psi the whole time. Could I have a restricted capillary tube? But why the studder-step on initial startup? Please help and soon. I may be shot at dawn if I don't get this fixed.Thanks, Neil"

[Forum Tech]

"Neil,Sorry about the delay.There have been a couple of fans in the kits that are drawing too much current and causing the module to shut the compressor off. It sounds like you may have one of these fans.If you can get a LED and connect it to the module, it will give a series of flashes when a fault occurs. This will be helpful in troubleshooting this. I suspect that you will be seeing two flashes. The diode connects between the small "+" and "D" terminals on the control module. The diode polarity must be observed. When the compressor stops, there will be a series of flashes followed by a pause. The diagnostic codes are here:www.rparts.com/Catalog/Major_Components/compressors/Danfoss/BD50F_compressor.pdfAnother common reason for this to happen is low voltage at the control module. Check the voltage at the power connections at the module when the unit is trying to start, and assure that it doesn't drop below 10.4 volts.If it turns out to be the fan drawing too much current, we will replace the fan. The newer kits will have a different fan that draws slightly less current.A quick test is to disconnect the fan and try starting the system. If it starts and runs normally, then the fan is the problem. It's ok to run the system for a few minutes without the fan. Watch the high side, and stop the system if it gets much over 250 psig.Hope this helps, please let me know.Forum Tech"

[Neil Calvert]

I have already tested for voltage drop and that is not the problem. I will test for this fan problem this morning. I purchased the optional extra fan for the controller. Can these fans actually draw that much current? Do they draw more than the coil of a relay? If so can I just add a relay to the system and run the fans thru the relay? I was thinking I might want to run a vent fan off the system also.

[Neil Calvert]

"Dear Forum Tech:I disconnected the fan as you suggested and it worked GREAT! I have turned it off, let the pressure equalize then back on several times and it has re-started every time. It has been running now about 45 minutes and the evaporator box is getting refrishingly frosty. The Ambient temperature here on the boat is about 65-70* right now and the system is running at 75-80 psig on the high side and 4 psig on the low side. (I put an external fan on the condenser for now.)Now I only have a couple questions:1. Are the pressures stated above in the normal range?2. Is my plan to run a relay (Rpart #017-1002, 12v) a workable option? That is what I plan to do unless you tell me otherwise. -- and we don't have to deal w/ the fan exchange and all that paperwork.3. I had read (in the forum or somewhere else) that the frost line out of the evaporator should only extend about 3 inches --- beyond the box? OR beyond the tubing insulation (3 ft. away)? My system has now been running about 90 minutes and is getting very cold. I have just turned it off, waited 5 minutes and restarted it and it started fine. Good call. Thank you.NeilHylas 44, "La Boheme""

[Forum Tech]

"Neil,1. Yes, with a large fan at these temperatures, the discharge pressure may be this low.2. Yes, that relay would be a good choice. Remember to size the supply wire adequately for the load you will be switching, and protect it with a fuse if necessary. The relay coil wires can be smaller.3. The frost line will vary a bit with changing loads, but we'd like to see not much more than three inches of frost beyond the end of the insulation. BTW, this system is designed so that the evaporator fan supplies cooling air to the module fan, the module fan really isn't necessary.Glad to help,Forum Tech"