12,000btu fuji
 

Right then....12000btu Fujitsu ductless in my shop. Popped in while the temps were -18C outside and checked the current on the unit....6.5A on each leg.

Anyone got a 1 ton to compare against? Might not be a fair comparison as I lost a bit of oil and doubtless a bit of gas as well over the recent cold spell.

Is yours 240 VAC ( single phase ) ?

I installed a 13 SEER 12,000 mini split A/C - Heat Pump , this summer . It is 120 VAC . Pulls about 10 amps , this last summer . Have not checked the amperage this winter ?

Does your Fujitsu heet well at -18C ? My HP starts to strain and take a long time to cycle off beginning around 25F .

God bless
Wyr

The Fuji is a 24 seer unit, IIRC 10.2 HSPF. 240Vac

It is not straining to heat but it doesn't seem to be shutting off so i couldn't tell you if it is near its limit. I don't have a basic air thermometer in the shop but I should get one.

My 13 SEER unit cycles , like a traditional A/C unit . My understanding is the high SEER units use a different technology .

The outside unit has sophisticated electronics to monitor the temps and pressures and the ability to modulate the power . The compressor is made to run at variable speed , paired up with the electronics .

The net results is , in stead of cycling the system off and on , the compressor changes speed with changing load .

So , your system may be slowing down , in stead of cycling ?

If your system is pulling 6.5 amps of 240 VAC , that comes down to a little greater wattage than my unit with 10 amps at 120 VAC , for cool ?

Not what I would guess for your high SEER unit ?

God bless
Wyr

Unfortunately it isn't a good comparison because the conditions are totally different. Maybe Xringer could chime in too or anyone else as well.

Using his data 6.5 amps x 240 VAC = 1560 watts .

My data 10 amps x 120 VAC = 1200 watts .

Admittedly , my data was summer time cooling , his winter heating .

But amps is amps , volts is volts and watts is watts .

I noticed he was quoting temperature in Centigrade / Celsius . I quoted temperature in Fahrenheit . So , he may be on the other side of the pond ? Or may be our northern neighbor ?

But no matter where we happen to be located on the globe , Newtonian physics seems to work pretty much the same .

God bless
Wyr

Fujitsu rival
 

Mikesolar

A homemade GSHP running on BBQ propane 2.5 T, and your familiar with it.

7.3 Amp @ 230 Volt 1 ph.

Just for comparison.

The O/S air temp -24 Deg C. Shop temp dips to 12 Deg. C Recovers to 16 Deg. by lunch time. Could use a little larger unit!!!

Randen


http://ecorenovator.org/forum/attach...i-install1-jpg

The issue is the the spread between indoor condensing temp (pressure) the evap temp (which in my case is -20C). Randen has a GSHP so the temp difference will naturally be narrower at -20C outdoor and current will be lower for the same pot.

Even the AHRI couldn't figure out how to measure efficiency with inverter systems, for the longest time. I guess that means that my value of 6.5A/leg is kind of irrelevant as it is just a snapshot in time.

What do your specs say as far as max run amps ?

You are correct , an an inverter system , the 6.5 amps may be though of as a snap shot of what it is doing as that specific time .

Did you measure the amperage going in ? The amperage going to the compressor would be difficult to calculate into watts . And it would not include the energy consumption of the fans .

Best of luck . :-)

God bless
Wyr

How did you lose oil and gas?

We had colder than -20C and the indoor was set at 60F (I haven't changed the control to read C yet), the lowest it would go, which means the compression ratio must be close to max. I noticed a bit of oily stuff running from the flare nut down about 4' of the large tube, inside the insulation and a drip on the ground. I assume if there was enough pressure to push the oil out, some gas would also come out but I am not going to do anything like pump it down till it gets warmer. It is still heating and because there is only 5' of line set, I should have an excess of gas and oil as well.

It didn't show any leaks when the outdoor temps were around freezing.

I just looked at the specs. The max running current should be 4.5A. Bummer. I better check as I may have bought a 1.5 ton unit (but I don't think so).

Did you use Nylog (AKA: "snot") on the flare faces and an actual torque wrench to assure that you were tightening your flare nuts to full specification when you put your line set together?

-AC

The torque wrench I have is for sockets but I have been doing gas flares for 25 years and this is the first persistent problem I have had with a R410A flare. I do use Nylog (I like the snot term) and my flare tool is the Ridgid swivel that I have been using for years without problems. I was told that a bit of oil loss is not an issue and the same fridgie told me that Mitsi said the pot can sometimes pull considerably higher than the max stated running amps. Remember that it was -20C outside.

The problem is, unlike a normal split system, inverters are hard to get true readings on and they often only give you one port for pressures.

I had a 1/2" torque wrench , as you said , for sockets .

I bought a 3/8" torque wrench and 3/8" drive metric " crows feet " . In both " normal " and flare nut version . I had read to position the crows foot at 90 degree on the torque wrench . ( 3 o'clock or 9 o'clock )

If the spec on the mini split is 4.5 amps of 240 VAC , then the watts are lower than my unit at 10 amps of 120 VAC . Which is what I would expect , since I remember yours was a higher SEER than my 13 SEER .

God bless
Wyr

Have you got a link to the "crows feet" thingies? Might make sense to get.

I may be criticized for buying at Harbor Freight ?

Search results for: 'crow foot'

The thing is , I have most of the " regular " tools I need on projects . But , I find myself needing special purpose tools for many of my projects . Often , I end up using them only one or two times , not enough to worry about wearing out the tooling .

So , I buy often Harbor Freight tools . The only real concern is , if I break the HF tool ? I try to take that into account .

Truth is , the quality of many of the HF tools has improved a lot , over the last 15 years . And , most of the time , you can visually tell the difference between HF tools that are good enough and those that are not good enough .

I am OK with good enough , I do not look for perfect , in this world .

Also , at my age , I am even less likely to wear out new tooling .

And , the truth is , moth of my torque wrenches are HF .

As a side note , my mini split HP is running , as I type this .

God bless
Wyr

I can tell you how I lost gas & oil .

I insulated both copper refrigerant lines , except the last foot or so . I had left that " bare " so I could cut to length & flare the ends .

I had the system up and running OK . However , both lines and the brass service valves were sweating , a lot ( late June ) .

I proceeded to finish insulating the bare metal . But I dumbed up and wiggled the small line enough to cause it to leak , at the flare nut . Unfortunately , I did not notice it , then . :-)

Latter that day , the unit quit working . Went outside and noticed oil on the concrete . This was on the weekend . Was not able to buy a jug of R410a until Monday . Or get in touch with of factory technical assistance until Monday .

I had obsessed about the loss of oil , all weekend . The technical support guy asked me how much oil I lost ? I described the puddle on the concrete . He told me not to worry , a little oil on concrete will spread out to a scary size puddle . He also told me the condensers are shipped with enough oil to accommodate the max length of line set , listed in the specifications .

When I told him I had the min 15 foot line set , he assured me I was OK .

Anyway , I re-did the flare , vacuumed the system down and weighed out the specified charge of R410a .

I bought a roll of cork insulating tape at Johnstone supply and CAREFULLY finished insulating the service valves and remainder of the copper lines .

Praise the Lord !

It worked and was still working ( in HP ) mode , a few minutes ago . When I was in the living room .

God bless
Wyr

PS This illustrates than many of my problems are self inflicted . :-(

I know quite a few ways of doing things , that do not work ! :-(

I can vouch for Nylog Blue for R410a and R134a ( automotive ) use . I think they make Nylog Red for mineral oil systems ? R12 or R22 units .

God bless
Wyr

So is the unit acting any different after the possible leak? This is the easiest way to tell. With an inverter unit, if you lost much gas, the compressor will run faster for longer each cycle.

The unit has an operation map in it, like a car. To find its place on the map, the compressor will have to move more gas from start-up. With R410a, the pressure difference is very high, so frosting and discharge temperature issues show up quickly compared to R22 systems. The inverter units are typically loaded to the gills with temp and pressure sensors so the controller can work well under a wide variety of conditions.

If the unit is still operating, I wouldn't sweat it too much. As long as you've sealed the leak, and the unit isn't tripping or faulting out, it's operating within its map. If it senses an abnormally low charge condition while running, it will most likely alert you to this condition. Like a car, the fault code may point to something else, but the unit will tell you something is awry.

Yes, the unit is working well and heats well. My fridgie friends are not too concerned but I am a bit because I don't know how much gas is still in it and the only way to really find out is to take it out and weigh in the proper amount. At -15c today, that ain't gonna happen

There have been no trips or lockouts of any type so.......I'll keep on, keeping on.

R410a
 

By the way , you all probably already know this . But , on the off chance some one does not , I will throw it in .

I read R410a is a blend / mix of 2 types / kinds of refrigerants . Instructions say to always charge with liquid ( tank up side down ) .

On my leak , I was fortunate enough to catch it while it still had a little pressure in the system . I valved off both service valves , so I did not have to worry about air / moisture entering the system .

Of course , it did when I re-flared the small line . When I vacuumed the system down , I was really only pulling a vacuum on the lines and the indoor fan coil unit .

I have read of the 3rd world method of just purging the lines with a little R410a gas . With the equipment , copper , insulation , tooling , etc. , plus the labor that went into the install . I was not about to take a chance on that method !

Besides , I had already made one dumb mistake ! :-( And , I had long ago acquired the tooling to evacuate the system .

By the way , my unit has only a 1/4" service fitting , on the large service valve . But not on the small service valve . I have since learned not to call them high pressure and low pressure valves / lines . I read that , in heat pump mode , the high side becomes the low side , and vice versa ?

I have read there MAY be a service fitting on the small line , inside the condenser cabinet ?

I am surprised , I figured the mini split would use the service fittings found on automotive R134a systems ? But mine does not .

God bless
Wyr

Nylog Blue also works on R22 and R12.

Good to know , Thank you . :-)

I did not know if it would contaminate the mineral oil ?

I have read that Nylog is polymerized refrigeration oil ? In the case of Blue , I guessed it was POE ester oil ?

Before I start up my central A/C condenser , next spring / summer , I need to swap out the Schrader valves . ( I have the tool to do this w/o discharging the R22 . )

The system has a very slow leak , that I have not found anywhere else in the system & Schrader valves are a likely suspect ?

I had planed to coat the new Schrader valves with mineral oil , but from what you have told me , Nylog Blue would be OK , too ?

God bless
Wyr

Service valve leaks are very common, especially if the installer didn't remove the valve cores while brazing the connections.

Huh???
 

Brazing connections? Why would you ever braze a flare connection? Please help, I don't get it.

Most central units in the US use brazed connections.