Mr Cool Leak: How to Fix?

[lawfarm]

I built a really nice backyard shed, heated/insulated/air-conditioned, a couple years ago...and installed a Mr.Cool mini-split for heat/AC. It's used as an office space.

A couple weeks ago, it started icing over when cooling. No extreme conditions (temps in the 80s/90s, no real humidity)--classic signs of low coolant. Called an HVAC service company to come check for leaks and service, for a $80 service call. They arrived, and suddenly, it's $500 for a basic service call because it was a DIY installation. (The install looks perfect and didn't leak at time of install; it's worked for 2 years. They just have a policy that any DIY systems are $500 for a minimum charge. I've called 2 other HVAC service companies with similar results.

$500 is half of what the system cost, and doesn't make a ton of sense...and that's before they even get into it and see what the problem is. I'm in the Folsom area, FWIW.

So...

How hard is it to find/diagnose a leak? I have zero HVAC experience before this (it was a pre-charged lineset install), and zero HVAC tools. Or keep looking for an HVAC company that's more reasonably priced? Or **** up the $500 charge because it's still half the price of replacing (and there's no reason to replace)? Or buy the tools and learn HVAC? Or other? No leaking oil, no obvious signs of leaks.

 

[Yankeefarmer]

Maybe talk to the people at MRCOOL or Ingrams to see if there’s an authorized MRCOOL service company in your area?

 

[danski0224]

Leaks are a ***** to find (as in actually find it, not just lie about it to a customer) unless there is something obvious like an oil stain.

R-410A isn't easy to pick up with an electronic leak detector like R-22. Buying a cheap one will hurt you.

Best thing to do is to check what the manufacturer recommends for a pressure for leak testing, it's usually 500 psi. There may be a "design pressure" on a tag somewhere, do not exceed that during testing.

For best results, you will need to recover *most* of the refrigerant and then pressurize it with nitrogen to the test/design pressure and then look for the leak using a sniffer or commercially available soap bubble solution made for leak testing.

Once located, repair or replace, evacuate, recharge.

Easy spots to check first are flare connections, whether you made the flare or used the line set as provided.

It will cost you more than $500 to buy the tools to do it properly.

The DIY surcharge is a **** show. Same process will be used to find a leak, no matter who installed it. I'd leave them a review about that. That said, looking for the leak would be strictly by the hour. You may hit $500 pretty quickly, and not find it.

 

[jjrbus]

Not a MR Cool but DIY Daikin. Daikin authorized tech shows up for $150, declares will add refrigerant for $130 lb and never looks for or mentions looking for a leak. Long story but office tells me to find another company! Anyway went over system with soap and water, couple times, no leak. Bought fancy high tech bubbles online, no leak. I have a cheap halogen detector but useless for anything but large leaks. Had system evacuated, pressurized with nitrogen and went over with fancy bubbles, no leak. Bought a hypersonic leak detector and when pressurized to 300 psi 1 or 2 leaks showed in 4 year old Daikin evaporator coil. A pain to do and $$$ but cheaper than adding gas and not looking for leak. After removing coil I tested in garage at 300 psi and confirmed 2 leaks with bubbles and possibly 2 more. Good luck