question about mini-split system

[Paul Clinton]

I recently got a quote on installing a mitsubishi mini split system. I was interested in installing a heat pump system to cool and heat some areas of my home. I have a 2 story colonial style house and from doing some research, I learned that I could condition up to 4 areas or rooms in my house using one outdoor unit and indoor blower in each area.

The salesman from a recommended company comes out and says I can only have one indoor blower per outside compressor. I then get a quote of two MUZFE12NA 23 SEER outdoor condenser/heat pump units and two Mitsubishi model MSFE12NA indoor blowers. This is to condition my lower level.

The salesman said I would need the same amount of equipment to condition my second floor, doubling the price.

Does this sound correct or am I getting bad info from someone trying to take me to the cleaners?

[wahoo]

You can do multiple indoor units with one outside condensor. I'd call another company and have them come out. We installed 3 indoor evap units on one condenser a few years ago, and they work fine. I think they were Diaken units, but not sure. Call another company as you're not getting the real story!

[Gib's Son]

Diakin, LG, Sanyo, Mitsubishi, they all have models that will do multiple indoor units off of one outdoor unit. Not sure about the models you listed but a quick visit to their web site would answer your question.

[Paul Clinton]

Thanks for your replies! I just called another company and they confirmed what you said. They will be coming out to give me an estimate.

[Paul Clinton]

Just one more quick question if I could. At what temp do these units become ineffective or innefficient for heating? I have read that they can provide heat down to approx. 15 degrees F.

[wahoo]

Different for each brand and whether or not they have built in strip heat. Make sure and discuss this with sales folks prior to purchase.

[chuckcrj]

Just one more quick question if I could. At what temp do these units become ineffective or innefficient for heating? I have read that they can provide heat down to approx. 15 degrees F.

The units you were quoted are Hyper Heat models which have full rated heating output down to 5° outdoor temp. Even below zero they still heat, the output is less than

Non Hyper heat models start dropping off at 20 - 30 and are down to very little heat at 0.

None of the Mitsubishi models have built in strip heat.

The limiting factor for using multiple indoor heads is the lineset lengths. Example; the MXZ-4A36 can only have a total connected line length of 230 ft with a max of 82 ft for any individual indoor head. There are limits to height difference too.

[Paul Clinton]

Thanks for your help wahoo and chuckcrj.
I have a guy from another company coming our Friday. It seems the Mitsubishi systems are popular in this area. In fact, they're the only systems I have seen in this area.

I have electric radiant heat in the ceilings in my house, which I actually like a lot. Very comfortible and mcuh cheaper than oil. When the temp gets too low i can still use that.

[SkyHeating]

Paul, where are you located as this is a big climate factor in system selection and sizing. Also do you plan on keeping the ceiling heat as a backup or just using the ductless?

Any Mitsubishi with a model number MXZ is a multi(X) zone(Z) system, they came in two, three, four and eight port units.

[mark beiser]

Depending on the total capacity involved, it may be worth stepping up to the next level from the multisplit units to a full blown VRF system.

Mitsubishi City Multi S-Series
http://www.mitsubishipro.com/media/226453/cmcatalog.pdf

Daikin VRVIII-S
http://www.daikinac.com/residential/...oducts&page=55

[Paul Clinton]

I'm located in central Massachusetts.
I do plan on using the ceiling radiant heat i currently have as I'm not sure I can reach everywhere in my house with the mini split system.