Hello everyone, I installed a Pioneer 12K BTU 21.5 SEER inverter mini split heat pump last spring to heat and cool my house. It has been running great all summer, but now that it is cold outside and I switched to heat mode I started running into issues with defrost. Long story short, I determined that the shrhrader valve is bad and is leaking refrigerant. I called their support and they told me since I do not have refrigerant or a recovery machine I can call an HVAC company out to fix the unit and they will refund me 75% of the total bill since it is under warranty, so I will only have to pay around $50. Cool!

I have a couple questions though.

1. According to the owners manual, the unit is charged for a 16’ line set, but is good up to 25. It also says to add 0.16 ounces of refrigerant for every foot of lineset beyond 16 feet if above 25. So since I Installed a 25’ lineset and I will have to have it recovered and recharged anyways since the refrigerant could be fractionated, should I request that the tech adds an extra 1.4 ounces of refrigerant to get the charge perfect for the lineset, or have it charged to the factory spec for 16 foot lineset since it’s good up to 25? It would seem like it would be ideal to add 1.4 ounces extra to compensate for the longer lineset, but I am not an expert.

2. Since this is an inverter mini split, from my understanding the only way they can be charged accurately is by weight and that charging by pressure alone isn’t’ accurate. Is that correct? The tech support guy told me it can be accurately topped off by pressure, but I don’t see how that could be done on a system with 1 service port and variable speed compressor.

Thank you very much in advance, I really appreciate your help.