How to Diagnose and Repair Restriction in Mitsubishi Mini Split HVAC Tech mini split troubleshoot

In this video, I’m diagnosing a mini split with a clogged strainer at the indoor unit flare fittings. It was a little difficult to diagnose initially, because the symptoms kept changing as many splits try to adapt in compensate for issues like restrictions, improper refrigerant charge, out of range temperatures, etc... my whole career I used to dread walking up to a call with a mini split because of all the headaches that come along with diagnosing them but the more I learn about these highly advanced systems the more I’m beginning to enjoy working on them. Let me know in the comments below how you feel about mini splits, thanks for watching!
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[@stevemas4966]

I had my doubts that you would fined the restriction but when you started to cut into the wall I figured you were onto something. Great job!

[@williamodle7715]

Really nice methodical, refrigerant circuit isolation diagnostic

[@HVACTechKnowledgy]

Appreciate that feedback and thanks for watching!

[@willardwilson6707]

Good find. Great video

[@HVACTechKnowledgy]

Glad you enjoyed it thanks for the visit

[@AirExcel-rb2je]

Thats was a great find man!! Very good video

[@jpenn727]

Wow, great diagnostic skills. Thanks much for sharing with us.

[@HVACTechKnowledgy]

You bet! Thanks for watching!

[@robd7365]

Nice find, and great troubleshooting. Was the evaporator freezing in cooling mode? And was the condenser constantly self-defrosting in heating mode? I have a unit that runs fine all winter in heating mode, but freezes up in cooling mode often in the summer

[@skipsaunders5974]

excellent video .... wish you were in my neighborhood ... :-) (Knoxville, TN)

[@HVACTechKnowledgy]

Thanks 🙏

[@JuanMorales-qn4tz]

Great video. Awesome job

[@HVACTechKnowledgy]

Thank you very much!

[@denuslevine210]

Interesting didnt know their woz a strainer in indoor liquid line flare section Youve a good understanding 😀

[@HVACTechKnowledgy]

Thanks! Glad it was helpful!

[@paulbryant68]

nice find!!! very nice…

[@chrissipple1018]

The bad thing about new equipment is the inverters. NASA started using them in 1960s for the project Mercury and they still can get them right. Good video

[@hernanjoseprietoherrera4839]

Thanks

[@juanrobles9511]

Very informative video , thank you 🙏

[@HVACTechKnowledgy]

Glad you enjoyed it thanks for watching!

[@ekie85]

That was a great search 💪🏽🤝🏼

[@HVACTechKnowledgy]

Thanks a lot!

[@rickross7796]

The installer should not have put the flares in the wall they could have come in with their linesets from the bottom left of the unit for access

[@Jason-wc3fh]

No. Can't comment on this particular Mitsubishi, but the vast majority of them give you roughly 18" of either brazed/metric style flares on their equipment that we don't use to adapt to our standard fittings. Their copper lines are always an off-size in millimeters that we don't typically use. It is stupid when the fittings are going to be left in a finished wall. Only when it runs out on exterior wall does it allow for proper servicing.

[@crowderglen]

Great video!

[@mariusm3595]

Awesome video !

[@HVACTechKnowledgy]

Glad you enjoyed it! thanks for the visit

[@squiglyace7346]

I’m trying to be like you

[@VincentCiani]

Awesome job!!!!

[@HVACTechKnowledgy]

Thank you!

[@scoobtoober2975]

aciq startup quick list to retorque flares when first using heat pump mode. once hot.

[@Daniel-vd9yb]

Bro where’s your gloves ! Shout out from Naperville good find

[@HVACTechKnowledgy]

I know sometimes I just neglect to wear them I definitely need to do better LOL

[@mikestevenson1819]

Good find

[@HVACTechKnowledgy]

👍

[@juanlanda2561]

Tough find!

[@alexholland7102]

Good video, but we do not see you FIX the restriction that drops the inside unit temp from -7F to 40F. Was cleaning the sand the only thing you did to fix 1) the temp difference on the strainer 2) the low temp (-7F, then 40F) on the inside unit? I know nothing about AC, so I may have missed it. Thank you!

[@WaffleStaffel]

Yes, it was the sand packed hard which was restricting the flow, acting as a metering device, causing the refrigerant to flash at the union, resulting in the temperature differential. An extremely sloppy install, allowing the uncapped line set to dig into the ground. It looks as though it was recirculating for a long time to make such an impacted obstruction, but it only traveled through the line and the 'evaporator', as there's a filter in the outside unit to protect the compressor. There must be even more sand in the screen or accumulator.

[@HVACTechKnowledgy]

Thanks! Yes, cleaning the sand was the only thing causing the restriction

[@Jason-wc3fh]

Impressive troubleshooting skills. I dread coming across these, but they're becoming a lot more common. Your thumb gives me the creeps with how far back your joint allows it to bend. Aside from your creepy thumb, this is good stuff here. I would assume install error with guys not sealing off their linesets.

[@HVACTechKnowledgy]

Thanks 👍

[@gregorygalati3435]

If my log gets into the stream even when using little, gets into strainers

[@eastcoast186]

👍👍👍thanks for video

[@HVACTechKnowledgy]

You're welcome I appreciate you watching!

[@aarongray503]

Where did you get those meter lead tips from? I got the sc440 and lost one of mine.

[@HVACTechKnowledgy]

Fieldpiece👍

[@bmobley1]

Whats the model of the fieldpiece bluetooth thermo couples your using?

[@robertolopez8146]

What kind of app you using with the felpice

[@HVACTechKnowledgy]

The app is called measurequick

[@TheLastBoyScout1976]

Why don’t you torque your flares to spec?

[@denuslevine210]

That & little bit more Only found 1/4inch flare nuts can crack

[@christopherprince3332]

So at 4:10 you mention you have 31 psi on low side and 56 on high side. Not so. Those are temperatures, specifically saturation temperatures hence the degree symbol along with and F just below the number. The psi reading you refer to is below your sat temps.

[@HVACTechKnowledgy]

Good catch yeah just misspoke and probably forgot to correct it in post appreciate the heads up and thanks for watching!

[@mountainklima5602]

why wood some one put those flares inside a dry wall , Better to weld them

[@HVACTechKnowledgy]

True

[@andyreyes6464]

what is the name of those small leads ?

[@supernintendo7579]

Needle leads

[@andyreyes6464]

Thank you

[@jbouchard667]

You had 100 psi on your low side and 161 on hi side. Not 31 psi and 56 like you said in video.

[@HVACTechKnowledgy]

yes sir, my bad I meant to say saturation temps on the video. thanks for the heads up

[@scoobtoober2975]

Don't dip the lines in mud, yikes i worry about where that stuff has gone.

[@chrisguillen1495]

I thought Mitsu didn’t want us to ever hook up gauges anymore.