Join Date: May 2012
Location: North Vancouver, BC
Thanked 48 Times in 45 Posts
Rep Power: 8
Re: ICM203 on break for boat HVAC unit
I agree, if you can find a solid state relay rated for 15a, with a 115v trigger voltage, that would be better, albeit more expensive, and harder to find. From looking at the control board schematic, it looks like they are using a simple PCB mounted mechanical relay, so there is no reason an appropriate sized general purpose relay wont work just fine.
While the anti short cycle time delay may resolve the problem, I am still interested in the root cause of the problem. While it is not uncommon for single phase compressors to have trouble restarting before they equalize, they usually cut out on their own overload device before they trip the circuit breaker. There are a number of other things to consider.
What is the breaker size, and what is the total load on the breaker? The manual for the 12mbh unit says RLA for the compressor is 9.4, and it also says to allow another 3.5a for pumps. That is still fine on a 15a breaker IF that is the true total load. Measure amps at the breaker, not the compressor to be sure.
I asked you what your voltage is, and you responded with an amperage number, and I see you made the same mistake in your blog. You need to understand the difference, and how they relate. Voltage and amperage have an inverse relationship. Your compressor may draw 9.5a at 115v, but if your generator is only putting out 95v, your amp draw will be higher. When you measure your voltage, measure it under load. If a power supply is struggling to handle a load, its voltage may drop when the compressor is on, even though the open circuit voltage looks good.
Your breaker may be borderline under sized. Circuit breakers work by heating up, so if you are pulling near maximum amperage through the breaker, it will be hot internally. If you then subject it to in rush current of the compressor restarting before it has a chance to cool down it could trip. Remember though, a breaker's role is not to protect your equipment, it is to protect the conductors of the feeder circuit, so you cannot upgrade the breaker's amp rating unless the wires are rated to handle that current.
Given that your unit was recently repaired by the factory, there is probably no problem with it, however if it is running high head pressure due to poor water flow in the heat exchanger, amp draw will go up. Without gauges you can't know what your head pressure is, but you can get a good idea by measuring the temperature of the refrigerant liquid line coming out of the heat exchanger. The refrigerant should go in hot, and come out cool, or slightly warm.
I also noticed that in your blog it looked like you disconnected the start capacitor. If that is the case, you should reconnect it. I didnt see anything in the EasyStart instructions that told you to disconnect it, but maybe I missed something.
Sent from my SM-G960W using Tapatalk
2011 Jeanneau 39i Azura