Hi,
We are having for almost a year now a MHI heat pump. (FDCW71VNX-A / HSB100 / RC-HY20). It is an air water version. In the summer period when almost having warm enough outside temperature there was a frequent arising error on low lp cool. At beginning of winter it gave the error of not being able to defrost. Sometimes it was indeed frozen in a way it could not work anymore, but most times the amount of frost should not be any problem. Installation manual mentions with these codes compressor could be stuck. Also, with these temperatures the energy consumption is way too high. Does anybody has any suggestions how to find out what the problem is?
Hi Nick, welcome to the forum.
The first place to look is probably MHI’s Troubleshooting Guide for your unit. I found a bunch of manuals here that could be useful:
Hopefully you’ll find some advice in there. Post back if you need help deciphering some text.
It’s important that there’s enough volume in the heating circuit to perform a defrost. If some thermostatic valves or zones have closed off, then there won’t be enough heat to melt the ice.
Thanks Tim! All valves for floor heating are open.
The flow chart for failed defrosting is very helpful. You can only check amount of coolant with official equipment right? Especially with that error in summer with low lp cool that is my first guess. Would you have any other suggestions of items I could check myself? The checking of coolant is on backlog of the installer and rather eliminate other causes instead oh just waiting.