VRF- Variable Refrigerant Flow systems

[gmcd]

Anyone got any comments, good, bad, or indifferent regarding these types of distributed DX systems? Daikon, Mitsubishi, Colt, etc. are flogging these systems as the latest and greatest solution to local zone HVAC control. I have some concerns about a lot of high cost/high pressure refrigerant pipes scattered through a building in terms of risk management. They claim a higher energy efficiency, but I think a good old two-pipe water to air packaged heat pump system wouldn't be that much worse, and you're only going to be dealing with low pressure water if it leaks.

[captinsano]

I would rather have a ref leak above ceiling tiles than water.Almost all supermarkets are piped over head,and besides most of the time if the piping in the overhead is tight after startup it is usually trouble free.The key though is a proper startup.

[hvacr]

We have installed 50 or more and I have started up over a hundred by know. Mitsubushi only. The only problem is no service calls

[salesslime]

These type systems are only new to U.S. Been in Asia and Europe for years. As stated, proper start-up is key.
The few people I know that work on them say service calls
are few and far between. The efficiencies are due to the
variable speed compressors.

[jbyrnes55]

This is the latest technology and it is not just a lot of BS. By the way, there are few failures, but you better know your HVAC before you attempt an install or service call.

[snowy24aug]

Do have some training and info before installing.

[flange]

we have done Daikin systems and find them to be trouble free. The energy recovery stuff is great and allows for even better efficiency while running some zones for heating and some for cooling. One packaged unit cannot give you the flexibility of these systems. They are very common outside the US and work well.

[MRcoolingMAGIC]

Anyone got any comments, good, bad, or indifferent regarding these types of distributed DX systems? Daikon, Mitsubishi, Colt, etc. are flogging these systems as the latest and greatest solution to local zone HVAC control. I have some concerns about a lot of high cost/high pressure refrigerant pipes scattered through a building in terms of risk management. They claim a higher energy efficiency, but I think a good old two-pipe water to air packaged heat pump system wouldn't be that much worse, and you're only going to be dealing with low pressure water if it leaks.

We are specialized in installation of these systems....and what i gather is that you dont have a clue ..what is happening with these higher pressures maybe that is why you posted so many " smart " words

[maxster]

CB magazine did a full story on this new application in their September issue http://www.contractingbusiness.com/

[jbyrnes55]

I don't know how we got so far off topic, but to get back to VRV technology, the stuff is great. It is not the death of chillers and package systems, only another solution that may provide better control while saving energy. If you look at the full picture, performance, longevity, low-energy consuption, ease of installation, low maintenance cost, self diagnostics, then these systems often out perform all the other technologies.

[rdy357]

Anyone got any comments, good, bad, or indifferent regarding these types of distributed DX systems? Daikon, Mitsubishi, Colt, etc. are flogging these systems as the latest and greatest solution to local zone HVAC control. I have some concerns about a lot of high cost/high pressure refrigerant pipes scattered through a building in terms of risk management. They claim a higher energy efficiency, but I think a good old two-pipe water to air packaged heat pump system wouldn't be that much worse, and you're only going to be dealing with low pressure water if it leaks.


The concept was born from Daikin in Japan 1982 and was a solution from the chiller group. They figured that they could move refrigerant more efficiently than water or air.
If the piping is done correctly it is a moot point. Just remember about refrigerant density in the space. ASHRAE 15 states R 410A at a max of 25 lbs per 1000 cu ft.

[jbyrnes55]

Are you an employee of Daikin??:)

[xarralu]

What happens when a compressor burns out!! I would like to know how you would clean up a system that is so large in piping length.

[OahuDave]

These systems are great and perfect for homes, condos, sm - med size offices. It's great especially if you want to save the landscape outside of the buidling since you can put multiple units for one condenser.

Also great for feeding multiple areas up to 4 tons and still use a single phase power. Get lot higher capacity on 3 phase of course.

Easy to design and implement. Easy to size equipment. No specialties (sight glass, TXV, solenoid valve, etc.) needed for the piping. Just piping and that's it.

Highly reccomend.

[kokinhvac]

According to the mitsu rep that came down for a brief class on the controls,there has not been any burnouts on the city multi compressors....i'm sure its possible but none to date!

[gmcd]

Surprised to see this thread still popping up after a year. Thanks to some for the feedback, although most of the comments still "sound" like the same sales hype we are getting from the sales reps here. I was hoping for some actual installed, running systems comments from other places in the world where these have been installed for more than the last couple of years.

It all comes down to trained installation and quality of the equipment, as witnessed by the other active thread about the Cimatemaster water source heat pumps discussion on this page.

[xarralu]

It sounds like a great idea one,cond. unit for multiple evap's but when not if the compressor goes out you'll have a big mess ahead of you.


Reminds me of a church that has their chill water and hot water on the same loop! What a joke!

[kiwicontroller]

Surprised to see this thread still popping up after a year. Thanks to some for the feedback, although most of the comments still "sound" like the same sales hype we are getting from the sales reps here. I was hoping for some actual installed, running systems comments from other places in the world where these have been installed for more than the last couple of years.

It all comes down to trained installation and quality of the equipment, as witnessed by the other active thread about the Cimatemaster water source heat pumps discussion on this page.

Well it doesn’t get much further then this ( NEW ZEALAND ) I have replaced a invertered compressor in a city multi Mitsh and its not much different you do your evacuation strip out the old compressor install the new one with a burn out drier using nitrogen bleed through and I always do multi vac's with oil changes between especially if the compressor burnt out, and the best way to re-charge the system is by Weighing your charge in. In Auckland VRV and VRF installs are becoming more popular and building owner are buying into the concept of individual zone control. Installation is key and a badly installed system will leave the service tech's frustrated.

[iHVAC]

Howdy!
Found this technology interesting and would appreciate any feedbacks from members who installed it and how it has been holding after these years (afterall this is an old thread ;) ).
Thanks!

[HvAckid82]

I went to the service class in boston and had a discussion with the instructor, who by the way is one of mitsubishi top techs. I asked about efficiency and he said it is more or less the same as WSHP. We have a building in NJ that is all CIty Multi and out of approx 10 condensers we had one compressor fail after 5 years of service. If the system was designed by a diamond dealer and started by authorized persons and have a 2-4 day record of operating pressures they will provide a warranty on compressors up to 7 years. The building owns has many many millions of square ft of real estate and he said this building consumes less power than any of his other buildings by 20% and this is not a green building.
The technology has been in Japan for numerous yrs and this is an everyday thing for them. I am waiting to see when Mitsubishi gets their 240 ton system UL approved for the US.
I have limited experience with the product, but what I do know is that if you think you know how to troubleshoot systems this will test your skills. Take sub cooling and super heat and throw it out the window along with your gauges. Get the laptop out and take a seat.
We have a lot of customers with WSHP and it is a PIA! You will most likely make much more money working on WSHP because there are many more service calls. As for climate master, junk, between control boards, contactors and refrigerant leaks climate master is for the birds. I personally like trane and water furnace but that’s my opinion. I am sure others will disagree.