EcoRenovator  

Go Back   EcoRenovator > Improvements > Geothermal & Heat Pumps
Advanced Search
 


Blog Register 60+ Home Energy Saving Tips Recent Posts Search Today's Posts Mark Forums Read


Reply
 
Thread Tools Display Modes
Old 01-21-11, 03:46 PM   #291
philb
Apprentice EcoRenovator
 
Join Date: Nov 2010
Location: Oklahoma City
Posts: 152
Thanks: 57
Thanked 17 Times in 14 Posts
Default

Xringer, I am looking at different systems for my new house. I appreciate you posting your experiences about the unit. I still have my eye on them even though there have been a few problems.
Since the new house will be owner built, I'm trying to put every line possible in the ground before pouring the parameter beams and going up with the building. Maybe some of the posters here would have some good advice for a non-HVAC person.

This tread had been very useful! Thanks!


Last edited by philb; 01-21-11 at 03:51 PM.. Reason: additional information requested
philb is offline   Reply With Quote
Old 01-21-11, 04:24 PM   #292
Xringer
Lex Parsimoniae
 
Xringer's Avatar
 
Join Date: Feb 2009
Location: Woburn, MA
Posts: 4,869
Thanks: 106
Thanked 244 Times in 224 Posts
Default

I can't recommend the Sanyo 24khs72, because of the idiosyncrasies that I have seen
in both of the outdoor units that I've had experiences with..

But, you should not be deterred from looking at inverter type mini-split systems.
These Inverter ASHPs are the best thing since light beer.

I think all the guys here are going to tell you, Insulate, insulate, insulate..
And of course you should have a LOT of south facing windows.

If I was designing a house, ALL the windows would be south facing!

Anyways, I can advise you to have the AC pad(s) poured with the foundation.
(Save you time and a little money later on).

If the unit (heat pump maybe) is going to be used mostly for heating,
being exposed to some sun is a good thing. But, if it's mostly for cooling,
locate the pad in a shady area.

Unless it's a big house, (needing many BTUs) it's not necessary for the pad
to be close to the main breaker box. These ASHPs don't use a lot of power,
so line loss isn't a big problem.
You also want to keep the length of the line-set(s) in mind. Shorter is better.
20 to 30 feet seems like a goal to shoot for.

Now that we have all this snow piling up..
And I'm thinking my Sanyo is going to be residing in a Snow cave before long,
If you are in an area that gets deep snow, you might want to consider an extra tall pad.
Maybe two feet off the ground.?. Cinder block construction?

Speaking of Snow, I'm learning that this Sanyo works best when it's not left
running during heavy snow.
So, it should always be used with a back-up heating system. Just in case.

I just left our Sanyo off for 12 hours of continuous snow. It snowed from
just after midnight until midday today. Right after it stopped, we cleaned it up
and turned the Sanyo back on.. It's keeping the house at 72F, using 480 watts.. (as I type this)

I recommend reading the install manuals for a few models of mini-split.
They will give you a real good idea of the requirements.
Xringer is offline   Reply With Quote
Old 01-21-11, 05:43 PM   #293
philb
Apprentice EcoRenovator
 
Join Date: Nov 2010
Location: Oklahoma City
Posts: 152
Thanks: 57
Thanked 17 Times in 14 Posts
Default

Thanks Xringer,
The unit will be used mostly for cooling in the summer and possibly as a backup for solar heat with radiant floors in the winter. I'm leaning more toward radiant propane heat in the winter. It depends on the price difference between the with and without heat mini splits. Here's a link to the propane heaters. MHVFR20LPBT - 20,000 BTU Propane powered radiant vent free heater

Over 90% of the windows will be facing south with a 5.5 foot overhang to keep the heat from coming through the windows in the summer. Both winter ice and summer heat can be brutal here.

Last edited by philb; 01-21-11 at 06:08 PM..
philb is offline   Reply With Quote
Old 01-21-11, 08:44 PM   #294
Xringer
Lex Parsimoniae
 
Xringer's Avatar
 
Join Date: Feb 2009
Location: Woburn, MA
Posts: 4,869
Thanks: 106
Thanked 244 Times in 224 Posts
Default

Have you been reading the 'Why Dig' posts?
http://ecorenovator.org/forum/geothe...html#post11196
There is some discussion about using gas..
At night or on cloudy mild days, when it's in the 35-68 deg F range, this Sanyo can keep
the house at a nice warm 72 F for peanuts. It could very well be cheaper than gas..

I have a friend up the street who installed a cooling-only min-split.
He is kicking himself for not spending an extra $200 to add heat.
He's using oil heat, like 90% of the people in this area.
It's now over $3 a gallon..

That's a nice looking heater. Not too costly either..

I like the sound of your design.. If I wasn't so old, I would love to start over again
in a house that was insulated to my specs..

Last edited by Xringer; 01-21-11 at 09:00 PM..
Xringer is offline   Reply With Quote
The Following User Says Thank You to Xringer For This Useful Post:
philb (01-22-11)
Old 01-22-11, 11:43 AM   #295
MN Renovator
Less usage=Cheaper bills
 
MN Renovator's Avatar
 
Join Date: Nov 2010
Location: Minneapolis, MN
Posts: 938
Thanks: 41
Thanked 115 Times in 89 Posts
Default

I've been looking at the mini-splits and started tossing numbers into the AHRI Certification Directory Variable-Speed Mini-Split and Multi-Split Heat Pumps section and air conditioner section.

There seems to be a huge disconnect amongst the way that efficiency works in these units. It seems that with standard central air units, to get better efficiency you need a cooling-only unit, which includes the Nordyne central-air inverter setups too. The inverter mini-splits have the highest SEER of any non-ground source air conditioner in the entire directory with 9,000 nominal BTU units at 26 SEER and 12,000 nominal BTU units at 25 SEER. Both Fujitsu but Mitsubishi, Toshiba Carrier, and LG have some that are close. For heating, I look at the ratio between low heat(14f) and high heat along with looking for a high HSPF since a very large portion of the winter heating in Minnesota is single digits and we dip lower fairly often which might cut the unit off completely.

It seems that SEER and HSPF both drop with SEER to closer to 20 or slightly lower if you want a size or sizes larger than these tiny ones. I've monitored my heating and for the Fujistu's minimum temperature rating of 5 degrees, I could probably keep my house up to temperature just with that tiny unit even with defrost cycles, I'd still need natural gas backup. The problem is at temperatures under 14 degrees, the only way I would save over a 90%+ efficient furnace(very cheap natural gas here) would be to use it in the room or area of the house I am in, such as the bedroom and allow the rest of the house to drop lower under setback.

If I had one, it would be upstairs in the master bedroom(where I sleep and don't mind surfing the net in on my laptop) and in my room I could aim it so it goes out the door and down the hall and with the second bedroom door open the airflow might reach to help with cooling if convection didn't do a decent job already. If the 12k unit couldn't keep up in the summer, I could section off(either partially or completely) the upstairs easily(smallish vault section opening for the stairs) and just cool that area and allow the rest of the house to get to a higher temperature and just use the central air for when I have people over or want to use the rest of the house but I'd probably only doing this during the hottest month of the summer or whenever the mini-split becomes undersized for the area. I once told someone about the 25 SEER unit and that I was interested, they thought 25 SEER was amazing but once I told them the capacity and price they shot the idea down quickly as being 'a very expensive way to cool just one room'. I think convection airflows are a bit more powerful than people imagine. He also hasn't seen my floorplan and why I think it would work well.
MN Renovator is offline   Reply With Quote
Old 01-27-11, 06:42 PM   #296
gogigaga
Lurking Renovator
 
Join Date: Dec 2010
Location: San Jose
Posts: 14
Thanks: 1
Thanked 0 Times in 0 Posts
Default

I've working on my installation off and on for the last few weeks. At last yesterday I completed installing my multi-zone system. With some hiccups all the tests and procedures went smoothly. I ran the AC for a few minutes in the night and everything seemed to be working fine. I wanted to run the AC overnight so put my bedroom inside unit to heat at 68 degrees. When I woke up all three units were showing error code CH26. So after a little research on the net I switched the outside unit off from the disconnect box for few minutes to reset the system. When I restarted the outside unit I ran all 3 inside units one at a time in test mode. The units turned off on its own after running for 18 minutes which meant the test was good. I think the test only runs cooler so I set one of the inside units to heat the room at 86 degrees. It started fine pumping out some heat in the room but after 5 minutes all the units again showed error CH26.
At this point I called LG technical support I was told that CH26 means "Inverter compressor seized." upon further research I found this page "http://www.hawco.co.uk/userfiles/MediaLibrary/LG%20List%20of%20SMS%20answers.pdf" which has the following explanation for error code CH25 "Inverter compressor seized. Check compressor windings all equal resistance 1 to 4 Ohms, check to earth 50 MOhm minimum, check run current and Inverter outputs". I could not figure out what this means exactly. I am hoping some on this forum could point me in the right direction.

Just now I reset the system again and just ran 1 inside unit at 86 degrees. it ran fine for a while but this time instead of an error the inside unit just shut down completely and I am not able to turn it on.

One thing I noticed and am not sure whether it is normal. When the outside units start it makes some noises. Somewhat like when you are trying to start a old car unsuccessfully.

Any help is appreciated.
gogigaga is offline   Reply With Quote
Old 01-28-11, 12:40 AM   #297
hotwire
Lurking Renovator
 
Join Date: Feb 2010
Posts: 21
Thanks: 4
Thanked 3 Times in 3 Posts
Default

What are the model numbers of the indoor and outdoor units? What are lengths of line set that are connected to the outdoor unit?
hotwire is offline   Reply With Quote
Old 01-28-11, 03:12 AM   #298
gogigaga
Lurking Renovator
 
Join Date: Dec 2010
Location: San Jose
Posts: 14
Thanks: 1
Thanked 0 Times in 0 Posts
Default

The outdoor model is LMU245HV and all the 3 indoor units are LMAN095HVT. The line set lengths are A=25ft, B=15ft and C=25ft.
gogigaga is offline   Reply With Quote
Old 01-28-11, 08:29 AM   #299
Xringer
Lex Parsimoniae
 
Xringer's Avatar
 
Join Date: Feb 2009
Location: Woburn, MA
Posts: 4,869
Thanks: 106
Thanked 244 Times in 224 Posts
Default pressure check

Did the install manual specify that you could use the built-in R410a charge with those line-set lengths?

(Without needing to add or remove some R410a)?

Since it tested good, I assume the charge started off okay (or close to correct), but now..?.

Since you can't turn it back on, I suspect you may have a leak.
Your R410a has slowly leaked down to a level that won't allow the system to start up.

I think it might be time for a pressure check. Since the system won't run,
you need to find out what kind of 'static' pressure should be seen at the fill/test port.

Edit:
I found the static pressure 201 PSIg. (at 70deg F)


If it's 70F outdoors and you see 201 PSIg, that means your system isn't bone dry.
It has 'some' R410a left, or, it could have too much.. (Which sounds very likely).

At the bottom of my label, I have LRA & charge info.

Last edited by Xringer; 01-28-11 at 11:11 AM..
Xringer is offline   Reply With Quote
Old 01-28-11, 09:15 AM   #300
hotwire
Lurking Renovator
 
Join Date: Feb 2010
Posts: 21
Thanks: 4
Thanked 3 Times in 3 Posts
Default

I think Xringer is on the right track, by doing the line set calcs your system, it is probably overcharged by 12.76 to 13.86 oz of refrigerant, depending on what chart I go by. That noise you hear at startup could be from the compressor slugging, and that's not good. These units are not plug and play. Refrigerant must be added or reclaimed if you vary from the factory pre-charge for the listed line length. One chart for your unit said it was pre-charged for 128' of line set, another said 123'.

If you take Xringer's unit as an example it came pre-charged for a 33' line set, he's running a 20' line set. If you look at the manual for his unit it says to adjust the charge .27 oz per foot, that works out to be 3.51oz. of extra refrigerant for his system. In his case, the unit runs fine until it tries to run at high speed, then he gets an overload condition.

Hope this helps,
Kenny

hotwire is offline   Reply With Quote
Reply


Tags
air conditioner, diy, heat pump

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 02:16 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Ad Management by RedTyger
Inactive Reminders By Icora Web Design