Daikin 5 ton Heat Pump info?

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JerryR

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I'm in the process of getting quotes to replace my central air heat pump system. I'm considering a Daikin 18 seer 5 ton system but I don't know much about this manufacture.

The system is a two speed compressor and variable speed air handler.

The current system is a Trane 4 ton, 2 zone with single speed compressor and variabke speed air handler. It struggles to keep up with the heat load on hot summer days.

Heat load computations from 3 AC companies calculated 4.5-4.78 ton requirement.

Any recomendations or suggestions?
 
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WorthFlorida

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Virtually all A/C manufactures use the same compressor, the Copland Scroll (http://www.emersonclimate.com/en-us...oll_compressors/Pages/scroll_compressors.aspx). It's the best there is for the 2 - 5 ton units. The air handler motor and the condenser motors are now all variable speed. Some are two speed but again, most manufactures buy off the shelf motors. One of the more common ones is called X13 for the air handler blower. Carrier uses their own specific motors and are very expensive (proprietary), $500-$700 to replace a fan motor. The only area that is usually manufactured specific is the electronics that control everything right down to the thermostats. The air handler box and outside unit usually are manufacture by themselves. The lower priced units (other than Trane and Carrier) out there may have off the shelf electronics and parts are ready available at suppliers, that is why many AC guys prefer these unit. Therefore, most A/C's are very similar with a lot of off common of shelf parts. How they use the electronics to control the units and with some intelligence plays on the SEER rating.

I googled Daikin and it looks like a European Company and starting up in Houston. (http://www.daikin.com/press/2015/150107/index.html) You have to find out what parts are they using and as a new player in the market if they have proprietary parts. There would be a limited source of parts and other techs or service companies that may not be able to service the unit.

I live in South Florida and it's almost all A/C only and at my other home (a Carrier unit that came with the house) in Orlando, that area is almost all heat pumps. Be sure to get the AUX heater in the air handler with the heat pump. The common choice for most A/C tech is Rheem or Lenox since their parts are not all expensive and can get them at the suppliers.

If your heat load is that high you might want to invest in some energy saving techniques unless your square footage is very high. If it's single floor home you might want to add a second unit and split the duct system. If one unit fails the second one can at least provide cooing in part the home and save money buy keeping one section of the home warmer if not occupied much. A two story it be more difficult.

So what is a good unit, I see them almost all the same. I have two A/C unit's for my S Florida home that are 13 years old with the Scroll Compressor. The only problems have been the electronic parts buring up, but since they are an OEM (Tempstar) it was cheap fix.
 

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Daikin is a large Japanese company, and the worlds largest manufacturer of variable-refrigerant-volume modulating heat pump & AC equipmen. Their US market share is very small relative their Asian presence, but they are a first-tier premium quality vendor.

They DO use scroll compressors, but I doubt very much that they buy Copeland compressors, but for all I know maybe they bought the company! (Daikin bought Goodman a year or two ago, and still sells the Goodman branded HVAC equipment, some with Daikin components inside.)
 

JerryR

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Daikin dealer is offering 2 Daikin options.

Option 1 has a 2-stage Daikin Heat Pump with a Copeland scroll compressor and variable speed air handler. It will have a Honeywell zone board with a pair of Honeywell Pro 9000 wifi thermostats. 16.5 seer, 56,000 BTU

Option 2 has a Daikin Variable-Speed compressor and infinitely variable speed air handler, inverter system. Includes all controls. 20.0 SEER, 52,000 BTU. 4,000 BTU less than option 1.

Both include a Daikin backed 12 year full parts and labor warranty.

Option 2 is $2,500 more than Option 1.

I'm reluctant to go for option 2 because of availability of experienced service techs and unique parts.

Do you think it's worth going for the inverter system? Of course dealers who don't sell, are not familiar or trained are bad mouthing the Daikin inverter system.

This experience is worse than buying a car.
 

Dana

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Makes me wonder if system #1 is a Goodman/Daikin hybrid or something... (in which case I'd be a bit wary.) The variable speed units are well-evolved members of the Daikin product line- a primary business of theirs.

Are you sure this place really needs 4-5 tons of compressor? Seems like a lot unless you have a lot of west facing window, or it's an unusually large house. For current code-min houses a ton per 1000' of conditioned space is usually conservative- many have cooling loads closer to 1 ton per 1500' of space, but old-schoolers still seem to insist on a ton per 500' rule of thumb, as if l0w-E glass had never been invented, and the walls all leak air like a sieve. Getting the load calculations right is the first most important factor, and hiring an HVAC contractor to do them usually ends up oversizing. Energy nerds (and sometimes insulation contractors) who don't have a compressor product to sell other than the accuracy of their calculations are much more likely to get it right.

And it may be possible to re-commission the 4 ton Trane along with with duct & insulation up grades and whole-house air sealing to make it work. An imbalanced &/or leaking duct & air handler placed in a vented attic outside the pressure boundary of the house can increase the actual cooling load by more than 20% when running, due to the air-handler driven air infiltration.
 

JerryR

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"Are you sure this place really needs 4-5 tons of compressor?"

Dana,

Thanks for replying. Your opinion is the most valuable to me.

Current unit is 4 tons and it struggles in heat of summer. Gotta remember this is Florida. Lots of single pane glass and about 5500 sq ft of dark shingle roof area (with radiant barrier) and R30 fiberglass batting in attic. . Biggest heat comes in on the South and West side windows.

I'm looking at 2-speed units because 1st stage will run compressor at 66% of full capacity (37,000 btu) If it needs extra it will throttle up to 100% (56,000 BTU)

I currently have a wifi thermostat and I have ability to view usage logs. Look at last July 21st. That day the max temp was 93 degrees, Mean 84 deg, Min 75 deg.

Thermostats were set at 82 deg and set back to 79 deg at noon. One zone ran OVER 3 hours and the other zone for 2 hrs 50 min before the interior temp reached 79 deg. This is with a 4-Ton unit. See below.

IMG_1823.PNG
IMG_1822.PNG
 

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Also, Air Handler is Horizontal ceiling hung in the garage and all flex ducting is in the Attic.

There are 3 returns in the ceiling with filters in the ceiling grills. Currently 2-ea 20"x20" grills w/14" duct and one 12"x12" Grill w/10" duct. We are adding one additional 20x20-14 and upgrading the 12" grill to a 16"x16" w/12" or 14" duct.

The last return needs to handle supply vents on south side of house when the bedroom door is closed. Those area has 6 supply ducts, a large bathroom, a dressing room, 3 walk in closets and a master bedroom.
 
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I decided to go with the Daikin 5-Ton Heat Pump, Inverter system. It uses a Daikin manufactured, variable speed Scroll compressor. With the variable speed air handler it specs out at 20.0 SEER.

I also went up into the attic with the rep. We are making several modifications to the ducting to improve air flow.


We are adding one more return and increasing the return size to the air handler. We are also reconfiguring the supply ducting to a 3-zone rather than the current 2-Zone. This makes more . Master BR area will be one zone. Great room and living area will be another zone. Family room and guest bedrooms will be 3rd zone.

We are also upgrading the return in the master BR which will allow me to close the BR door and run that side only if desired.

They are using 3 CTK04 communicating thermostats connected to a EWC Ultra-Talk 3000 Communicating Zone Control System. Also included is remote outdoor temp sensor and Internet gateway so that the communicating thermostats can be monitored and controlled remotely.
 

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Installed last Wednesday-Thursday.

You can see how much each zone is calling for and how much the system is delivering on the LCD display on the EWC Zone Board.

It's been running between 15-33% compressor output when its running.

The thermostats allow you to get into configuration and see the CFM, Requested compressor, Actual compressor output Condenser Fan speed, pressures etc.

Right now the bedroom zone is blowing too hard at 1150 CFM with 25% requested output is called for right now. Waiting for Engineers to come up with a programing solution to slow down the Air Handler fan when the one zone is calling. If not we may have to put in a powered bypass damper.

Gotta love 20 seer.
 

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Variable speed systems are great for both efficiency & comfort when sized right and dialed in. On continuously variable systems you even get a slight efficiency boost with a modest amount of oversizing, but oversizing by more than 1.25x or so may lead to lower comfort, since they can only go so slow. When cycling on/off at min-modulation you end up with bigger temperature & humidity swings.
 

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Techs came out yesterday and were able to adjust low, intermediate and high fan speed ranges (CFM) via "trim" settings for each each zone individually via programming. they were also able to adjust compressor requested % individually for each zone and combined zones at the zone board. There are several fan profiles to select. The one in use starts at 50%, then goes to 80% and if not satisfied after 8 minutes to 100%.

Right now it's 84 degrees outside. Compressor speed starts at 16% and normally levels out at 26%. the AC runs for much longer periods of time at low heat load times of day. The discharge air temp and volume (BTU output) seems much less than previous system. We don't feel the temp swings we did with the old system.

It seems to be pulling more of the humidity out allowing for comfort at higher inside temps.

There are 3 computers that communicate via data lines that have ability to make changes. Each thermostat, the zone board and the Heat Pump outdoor unit.

Another cool thing is I added a few remote inside temp sensors that can be linked wirelessly to individual theremostats. I have option of choosing which device controls temperature or they can be averaged. You can link up to 6 remote temp sensors to each thermostat.
 
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Update; DAIKIN SUPPORT!

Last week the local installing company asked if they could come by with Daikin Factory reps who were going to be in town. Daikin had an engineer in from Japan who was visiting sites. Another Daikin US engineer (PhD) from Texas, a local Daikin tech rep and regional Daikin tech rep. So 4 Daikin reps, one lead local installer's tech and owner of local A/C company spent 5 hours at the house.

The EWC zone board rep was on the phone with them also. The only company not represented that day was Honeywell who provided the communicating thermostats.

The Daikin Japanese engineer connected his laptop to the outside unit to monitor operation while they tried numerous combinations. He spoke very little English but enough to direct what he was doing and wanted.

They were able to fine tune so that essentially there is zero temp swing in any part of the house. There is no air flow noise from any register or return.

This system has a Daikin provided 12 year parts and labor warranty.

I'm very impressed with Daikin and support from local AC company.
 

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Virtually all A/C manufactures use the same compressor, the Copland Scroll (http://www.emersonclimate.com/en-us...oll_compressors/Pages/scroll_compressors.aspx). It's the best there is for the 2 - 5 ton units.

The scroll compressor in the 5-ton Daikin inverter system is Daikin manufactured and completely variable speed, not 2-speed and not Copland.


The air handler motor and the condenser motors are now all variable speed. Some are two speed but again, most manufactures buy off the shelf motors. One of the more common ones is called X13 for the air handler blower. Carrier uses their own specific motors and are very expensive (proprietary), $500-$700 to replace a fan motor. The only area that is usually manufactured specific is the electronics that control everything right down to the thermostats.

Daikin. Has 12 year parts warranty standard and most dealers throw in 12 year manufacture labor coverage so parts cost is of little concern.

I live in South Florida and it's almost all A/C only and at my other home (a Carrier unit that came with the house) in Orlando, that area is almost all heat pumps. Be sure to get the AUX heater in the air handler with the heat pump. The common choice for most A/C tech is Rheem or Lenox since their parts are not all expensive and can get them at the suppliers.

I currently own 3 Florida homes. It seems that straight cool systems with heat strips are the norm for homes south of "The Lake" and heat pump systems north of the Lake. Our new unit in our Sarasota area home is Heat pump w/8Kw aux heat strips. I have the strips programmed out as the old 4-ton heat pump never needed the strips. If the heat pump fails it's simple to put the system into emergency heat mode and power up the strips.

Our Ft Laud hone has straight cool with 12kw strips as only heat source.

Our other west-central Florida home has a 2 1/2 straight cool for master BR side and a 3 1/2 ton heat pump for living area.
 

Dana

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"Our Ft Laud hone has straight cool with 12kw strips as only heat source."

I'm just trying to imagine what a home in Ft. Lauderdale looks like that would have a heat load as big as 12kw (41,000BTU/hr) @ 50F (Ft. Lauderdale's 99% outside design temp.) That's more heat load than my house at 0F.

The heat strips are a bit oversized for the load- is it a matter of the air temp at the registers being too low even at the lowest air handler speed if the strips are sized for the true heating loads?

Good feedback on the Daikin tech support! It's consistent with what I've heard from others.
 

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Yeah, it's overkill. We rarely use heat in Lauderdale but when needed it gets toasty quickly.

The Ft Laud house has a 4-ton straight cool Rheem with the heat strips. A few years ago I was out of town and the AC ran solid for two days according to neighbor. I measured temp at registers and it was 80 deg. I found that the heat relay was engaged all the time turning on the strips and fighting the AC. I unplugged the strips from the relay and it got cool again until I could get replacement part.

I installed wifi thermostat after that so I could monitor and control AC when away.
 

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JerryR,

A nice informative post and you bought a real nice system. The variable speed compressor is something new whereas most others are two speed. Trane, Carrier and others do now have build in dehumidification features but at a much lower rate and therefore lower cost to cool.

Many people up north have no idea how hot it gets in S Florida and many parts of the south during the summer (May-Oct not June to Aug) and the humidity levels are way up there. Therefore, cooling calculations are far different. As you stated most homes in the state are built with single pane glass and the old storm windows are non-existent. Code requires all replacement windows must be impact resistant glass unless there are storm shutters installed and on new homes as well. Some are offered with low e glass. Up north trying to keep a home at 70 degrees when it is 30 degrees outside, that is a forty degree difference. In Florida, when it is say 90 degrees and trying to keep the home at 76 degrees, that is only a 14 degree difference. Therefore, windows just doesn't play in the building requirements for energy efficiency but safely from hurricanes do.
 

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This system has dehumidification but we turned it off. Zones are running between 44-50 RH with dehumidification turned off.

With the system maintaining the humidity at a constant low due to variable speed system we find that we stay comfortable with higher temps.

Right now the outside temp/humidity it's 91.4 deg and 64% RH. I have all thermostats set at 79 deg and it's very comfortable w/44-47% RH inside. The compressor is running at 28% capacity and air handler at only 650 CFM. Not bad for a 5 ton unit.

Even though it's advertised as a 5 ton unit it is rated at 54,000 BTU and 20 seer as configured. At 28% it's only providing a constant 1.25 tons or 15,000 BTU to offset the heat load.

The other thing is with the variable compressor you don't get the current surge when it starts up like the previous system.


---------

image.jpg
image.jpg
 
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JerryR

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Update:

The unit is outstanding when operating properly, unfortunately it's been plagued with intermittent issues.

I was initially reluctant to be the first installation of a 5 ton heat pump inverter system with zones.

Occasionally in high heat load days this summer it slows down to 650 CFM with compressor output of 25-30% when thermostats and zone board are calling for 100% output. This is not enough output to offset heat load and temp creeps up significantly. Being heat load is different on each zone, to the high heat load zone temp gets uncomfortable. Power cycling the unit seems to resolve the issue temporarily for a few hours then it slows down again.

Daikin factory reps have come in from Texas on 3 occasions to assist local company. The replaced the EWC zone control board with new version, which seems to have made it worse.

I have requested they remove the unit and instal a more conventional 2 stage compressor with variable speed air handler. Thus will require a EWC hand damper and EWC powered bypass damper.

The tech that has been working with me is outstanding. Late Friday he came out with a new chip for the AC control but recommended he wait until Monday to replace it in case it causes failure.

I'll report back with final resolution.
 

mdfred

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Virtually all A/C manufactures use the same compressor, the Copland Scroll (http://www.emersonclimate.com/en-us...oll_compressors/Pages/scroll_compressors.aspx). It's the best there is for the 2 - 5 ton units. The air handler motor and the condenser motors are now all variable speed. Some are two speed but again, most manufactures buy off the shelf motors. One of the more common ones is called X13 for the air handler blower. Carrier uses their own specific motors and are very expensive (proprietary), $500-$700 to replace a fan motor. The only area that is usually manufactured specific is the electronics that control everything right down to the thermostats. The air handler box and outside unit usually are manufacture by themselves. The lower priced units (other than Trane and Carrier) out there may have off the shelf electronics and parts are ready available at suppliers, that is why many AC guys prefer these unit. Therefore, most A/C's are very similar with a lot of off common of shelf parts. How they use the electronics to control the units and with some intelligence plays on the SEER rating.

I googled Daikin and it looks like a European Company and starting up in Houston. (http://www.daikin.com/press/2015/150107/index.html) You have to find out what parts are they using and as a new player in the market if they have proprietary parts. There would be a limited source of parts and other techs or service companies that may not be able to service the unit.

I live in South Florida and it's almost all A/C only and at my other home (a Carrier unit that came with the house) in Orlando, that area is almost all heat pumps. Be sure to get the AUX heater in the air handler with the heat pump. The common choice for most A/C tech is Rheem or Lenox since their parts are not all expensive and can get them at the suppliers.

If your heat load is that high you might want to invest in some energy saving techniques unless your square footage is very high. If it's single floor home you might want to add a second unit and split the duct system. If one unit fails the second one can at least provide cooing in part the home and save money buy keeping one section of the home warmer if not occupied much. A two story it be more difficult.

So what is a good unit, I see them almost all the same. I have two A/C unit's for my S Florida home that are 13 years old with the Scroll Compressor. The only problems have been the electronic parts buring up, but since they are an OEM (Tempstar) it was cheap fix.
 

JerryR

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Update:

The unit is outstanding when operating properly, unfortunately it's been plagued with intermittent issues.

I was initially reluctant to be the first installation of a 5 ton heat pump inverter system with zones.

Occasionally in high heat load days this summer it slows down to 650 CFM with compressor output of 25-30% when thermostats and zone board are calling for 100% output. This is not enough output to offset heat load and temp creeps up significantly. Being heat load is different on each zone, to the high heat load zone temp gets uncomfortable. Power cycling the unit seems to resolve the issue temporarily for a few hours then it slows down again.

Daikin factory reps have come in from Texas on 3 occasions to assist local company. The replaced the EWC zone control board with new version, which seems to have made it worse.

I have requested they remove the unit and install a more conventional 2 stage compressor with variable speed air handler. Thus will require a EWC hand damper and EWC powered bypass damper.

The tech that has been working with me is outstanding. Late Friday he came out with a new chip for the AC control but recommended he wait until Monday to replace it in case it causes failure.

I'll report back with final resolution.


Final solution. Better later than ever.

Factory rep and local dealer expert came out and did the following.
1- replaced the main board in the outside unit. They were unable to flash the original board chip back to original software.
2- adjusted the TXV expansion valve superheat
3- Replaced the EWC Zone board with a new BETA version. EWC used my data and suggestions on software changes. You can now set zones proportionally by 1% increments. I have zones set to 45%, 40% and 15%. With new software output is limited to 2X the zone % Example if the small zone is the only zone calling for cooling and it's calling for 100% the AC capacity maxes at 15 x 2 or 30% capacity. if all zones are calling for 25% capacity the AC capacity will not exceed 25 x 2 or 50% output. The AC compressor now runs ALL DAY and modulates between 30-70% capacity (between 1.5 ton to 3.5 ton) during the heat of the day. This keeps the house very comfortable humidity wise.

I was recently on a conference call with EWC chief engineer and their circuit board manufacture. They were very appreciative of my feedback and detailed notes. They used my feedback to redesign the software. They told me I have a lifetime warranty on all their products installed and if I every need anything they would send it for free. I took them up on this last week and they sent me 2 powered dampers and a Smart bypass damper for my daughters house at no charge.

Everything is now working perfectly! Temperature in the house doesn't vary more than 0.2 degrees in any zone. AC modulates all day long from 25% to 76% based on heat load. You can view % calling per zone, system capacity output and discharge air temperature DAT on the zone board digital display.
 
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