First video of yours I’ve seen - you are well fucking done, brother. I’m a certified Mitsu tech support/instructor/commissioning and you explained that more simply than anyone I’ve ever heard. These are not simple lmao, but you gotta KISS to really grasp it.
Be sure to check for small leaks were they installed the ball valves!! The both of the last TWO boxes have came from the factory with leaks! The first ones the leak was big enough that I was able to find it with my hand. The second one was very small and I had to use bubbles. There is no way that they pressure test them at the factory.
You can order them with them preinstalled, the model of the BC just has a BV at the end of it. I was going to order that one but they said they take forever and they had this one in stock. Sounds like I made the right choice if they leak from the factory. How annoying.
The VRF is really a complicated system. We had an issue with broken check valve and the debris got mixed in the refrigerant. Had to take about 100lb of charge out of the system and put a new check valve assembly in it. Took about 2 days to bring everything back in working.
tell me about it....i got an entire floor where everyones tstats are addressed wrong and control the wrong units...idiot installers messed it all up....nothing was labeled correctly ..trying to find someone who has the laptop and software .....im used to only needing a set of gauges and multimeter and m good to go...not this time lol
im just learning these systems ..ive got a 58 unit building with this system i work at.....im used to just needing a set of gauges and a multimeter and im good to go...
Incredible video. I’m a first year apprentice. You made it very easy to understand. I have a question, the saturated high pressure and low pressure lines, how does that work with the compressor? And are you saying LEV….what does that stand for? Again, incredible video…I imagine troubleshooting these systems are very complicated.
Thanks a ton! We control the refrigerant temp/state by increasing fan speed and also opening up more sections of the outdoor coil! Outdoor unit is able to maintain a saturated state in the high pressure line by choosing to do any of the above.
I've always wondered how they're heating when the outdoor unit is in cooling mode,, so with the outdoor unit creating very little or next to no subcooling and utilizing the gas, liquid separator your able to heat.. now your typical hot gas line temperature will be anywhere from110-160*.. a 2 pipe setup would be much lower, which is why I hear the 2 pipe isn't quite as good heating in cooling mode.
I really appreciate the great info. Let me ask what happened to have to replace a whole branch box? It appears to be somewhat serviceable. Sorry if I sound dumb but I am mainly a residential tech.
Hello!! very good video and good explanation, thank you for sharing your knowledge, I am writing to you because I have some questions. When you explain the cooling-only mode, you talk about a subcooling of 0 to 2 degrees in the liquid that comes from the outdoor unit to the BC separator. How do you calculate the subcooling, that is, with what temperature probes or pressure transducers? In the same operating mode (refrigeration) you also need to subcool that liquid more in the two subcoolers, in the first from 9 to 27⁰ and in the second from 27 to 54⁰. I would also like how to calculate, that is, where do I take my measurements, temperature probes or pressure transducers? Thank you very much for your answer.
Do you have a video that shows how to test the CMB unit crossing ports to IC units. There are a few ways to test whether connecting a CMB port to a specific IC unit is correct. Do you have something to share with us? B.T.W - we love all your videos. You help everyone a lot
Hey mate, g'day from down south. I like the simple explantion, especially the saturated high pressure pipe from the outdoor. When in mostly heating, the FCU calling for cooling takes liquid and meters in into it's coil, but that vapour will be very low pressure (and temperature). How does the branch box create enough suction to take that low pressure vapour? Is the low pressure pipe to the indoor pretty much at suction pressure of the compressor?
@@HungryTradie so it's imagine the fcu is 1000ft away from the odu. The odu is on the roof of a 5 story building and the fcu in quiestin is on the first floor. The sat temp of the fcu is 40°. At the odu, sat is 32°. The pressure in the coil is higher, then the suction gas drags along the walls of the piping, dropping in pressure over its long journey back to the compressor. So pressure/temperature is much lower at the ODU than it is at the fcu.
@@VrfMadness thanks mate. I'm thinking that one pipe is always high side (saturated gas and liquid). The other pipe is always low side (maybe not suction, but always low), right? That means oil could never make it back to the outdoor, so they must separate oil from the high side saturated liquid, right? So: my unit dripping oil from its "Y" pipe join of 2 outdoors is bad, m'kay.... Must have an issue with an oil separator in the outdoor.
@@HungryTradie correct! And no, oil is fine. It is separated at the ODU but its scattered throughout the entire system. Anytime you have a system that has a leak, there will be a TON of oil at the leak location.
How many people in the planet can repair these the more they Tinker with the plumbing the easier it's going to break I am pleased that you can wrap your head around this wait 7 years you'll have a lifetime job there
For a Mitsubishi VRF system, if one FCU (Fan Coil Unit) is not turned on, the other FCUs won't cool. However, if that FCU is turned on, the others start cooling. What could be the problem?
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Very very interesting! I haven't seen this branch box before. That's a really clever way to heat/cool simultaneously without having a third pipe
Back in my first days we didn’t need laptops to troubleshoot an HVAC system and we rode our dinosaurs to the service call.
How'd you cool the pyramids
@@AgentOffice ductless mini-splits
@@jfrancis98 with solar inverters?
@@Art-si7cj true if it's very low humidity
Im completely stunned mate, thanks for the knowledge!
Nice video, some grocery stores i service have VRV’s and trying to understand how they work out in the field is the worst
Reminds me of the Husman Kool Gas defrost system to make a differential.
Great walk through of a branch selector box
First video of yours I’ve seen - you are well fucking done, brother.
I’m a certified Mitsu tech support/instructor/commissioning and you explained that more simply than anyone I’ve ever heard. These are not simple lmao, but you gotta KISS to really grasp it.
I really appreciate that! The quote that lives in my head is "if you can't explain it simply, you don't understand it well enough."
I always just called it the "magic box" 😂
You're not far off!! 😂
Be sure to check for small leaks were they installed the ball valves!!
The both of the last TWO boxes have came from the factory with leaks! The first ones the leak was big enough that I was able to find it with my hand. The second one was very small and I had to use bubbles.
There is no way that they pressure test them at the factory.
I installed the ball vales myself, but that's really good to know! Very disappointing to hear that
@@VrfMadness They use to come without the ball valves but the last two came with them already installed and they both leaked.
You can order them with them preinstalled, the model of the BC just has a BV at the end of it. I was going to order that one but they said they take forever and they had this one in stock. Sounds like I made the right choice if they leak from the factory. How annoying.
Thanks. I didn't know that
Back in my day we put ice in front of a fan.
lol
Great video. For branch boxes installed outside with the cables coming out of the top - Should they be covered ?
The VRF is really a complicated system. We had an issue with broken check valve and the debris got mixed in the refrigerant. Had to take about 100lb of charge out of the system and put a new check valve assembly in it. Took about 2 days to bring everything back in working.
tell me about it....i got an entire floor where everyones tstats are addressed wrong and control the wrong units...idiot installers messed it all up....nothing was labeled correctly ..trying to find someone who has the laptop and software .....im used to only needing a set of gauges and multimeter and m good to go...not this time lol
im just learning these systems ..ive got a 58 unit building with this system i work at.....im used to just needing a set of gauges and a multimeter and im good to go...
Great info. and demonstration.👍👍👍👍👍👍👍👍. Thank you.
wow great video. i love how the second subcooler works
Very good explanation.
Incredible video. I’m a first year apprentice. You made it very easy to understand. I have a question, the saturated high pressure and low pressure lines, how does that work with the compressor? And are you saying LEV….what does that stand for? Again, incredible video…I imagine troubleshooting these systems are very complicated.
Thanks a ton!
We control the refrigerant temp/state by increasing fan speed and also opening up more sections of the outdoor coil! Outdoor unit is able to maintain a saturated state in the high pressure line by choosing to do any of the above.
LEV is linear expansion valve. Essentially just an electronic metering device.
@@VrfMadness Interesting. Looking forward to more vids!
I've always wondered how they're heating when the outdoor unit is in cooling mode,, so with the outdoor unit creating very little or next to no subcooling and utilizing the gas, liquid separator your able to heat.. now your typical hot gas line temperature will be anywhere from110-160*.. a 2 pipe setup would be much lower, which is why I hear the 2 pipe isn't quite as good heating in cooling mode.
Correct, 2 pipe is a bit more inefficient.
I really appreciate the great info. Let me ask what happened to have to replace a whole branch box? It appears to be somewhat serviceable. Sorry if I sound dumb but I am mainly a residential tech.
@@mattluongo7763 no dumb questions! It had a leak in an area that wasn't able to be fixed.
@VrfMadness dame bet that was expensive for the customer
Hello!! very good video and good explanation, thank you for sharing your knowledge, I am writing to you because I have some questions. When you explain the cooling-only mode, you talk about a subcooling of 0 to 2 degrees in the liquid that comes from the outdoor unit to the BC separator. How do you calculate the subcooling, that is, with what temperature probes or pressure transducers? In the same operating mode (refrigeration) you also need to subcool that liquid more in the two subcoolers, in the first from 9 to 27⁰ and in the second from 27 to 54⁰. I would also like how to calculate, that is, where do I take my measurements, temperature probes or pressure transducers? Thank you very much for your answer.
Do you have a video that shows how to test the CMB unit crossing ports to IC units. There are a few ways to test whether connecting a CMB port to a specific IC unit is correct. Do you have something to share with us?
B.T.W - we love all your videos. You help everyone a lot
@@hagaisaar2560 thanks for the support!
I will work on a video discussing that soon for sure!
Think of a parallel Refrigeration rack w/ hot gas defrost.
Hey mate, g'day from down south.
I like the simple explantion, especially the saturated high pressure pipe from the outdoor.
When in mostly heating, the FCU calling for cooling takes liquid and meters in into it's coil, but that vapour will be very low pressure (and temperature). How does the branch box create enough suction to take that low pressure vapour?
Is the low pressure pipe to the indoor pretty much at suction pressure of the compressor?
@@HungryTradie so it's imagine the fcu is 1000ft away from the odu. The odu is on the roof of a 5 story building and the fcu in quiestin is on the first floor. The sat temp of the fcu is 40°. At the odu, sat is 32°. The pressure in the coil is higher, then the suction gas drags along the walls of the piping, dropping in pressure over its long journey back to the compressor. So pressure/temperature is much lower at the ODU than it is at the fcu.
@@VrfMadness thanks mate. I'm thinking that one pipe is always high side (saturated gas and liquid). The other pipe is always low side (maybe not suction, but always low), right?
That means oil could never make it back to the outdoor, so they must separate oil from the high side saturated liquid, right?
So: my unit dripping oil from its "Y" pipe join of 2 outdoors is bad, m'kay.... Must have an issue with an oil separator in the outdoor.
@@HungryTradie correct! And no, oil is fine. It is separated at the ODU but its scattered throughout the entire system. Anytime you have a system that has a leak, there will be a TON of oil at the leak location.
How many people in the planet can repair these the more they Tinker with the plumbing the easier it's going to break I am pleased that you can wrap your head around this wait 7 years you'll have a lifetime job there
Thats a lot of shit to go wrong.
Mitsu rarely fail
they work great until they dont..
Great clear explanation. Where do you get your training?
Thank you! I work on it everyday. I also received training from mitsubishi when I had first started working on their equipment.
How do you use nitrogen when you're brazing??? Can you explain the right way
For a Mitsubishi VRF system, if one FCU (Fan Coil Unit) is not turned on, the other FCUs won't cool. However, if that FCU is turned on, the others start cooling. What could be the problem?
On the ref cycle diagram on the maintenance tool, whats the HIC on the BC box? Is it the sub coolers?
Yes! They are the sub coolers.
@@VrfMadness Perfect. Thought as much but never received training on using the mnet tool
Thank you, when can I buy you lunch, great video!!!
Thank you!!
What is the 3rd pipe going downstream? How can the defrost work, one would expect the suction line to just get so cold it won't evaporate?
3 pipes going to the sub BC are hot gas, liquid, suction.
It's only in defrost for a very short time.
Whats this unit ?
Good video why are you changing the full bc box?
It's leaking in a spot we can't fix.
@@VrfMadness 👍🏼good work!
Lovely job
how does subcool twice with out a heat exchanger plate ?
It is a tube in tube heat exchanger.
@@VrfMadness so is kinda like a plate subcooling or like the water source heat pump condenser
@@VrfMadness great answer, thanks
How much was that??????
I think the whole job was like 14k if I remember right!
thanks 🙏
Heet ricovri pump Vrf ❤
wow