Sanyo 24KHS72 AC/HP DIY install project

[Xringer]

Is this gauge any good?

Gauge 2" Vacuum Gauge 0-30"HG (0to -1 BAR) 1/8 NPT - eBay (item 180406066600 end time Oct-09-09 16:45:04 PDT)


Hey, owning a vacuum pump might be useful for other stuff too.
And, like you said, I can always sell it..

I just read the manual for the AC only unit (borrowed from work) and it
said to vacuum down the lines to 10 mmHg abs, shut off the pump,
then release some R410A into the lines (for 10 seconds), shut it off
and then do a soap bubble test on all the fittings..

That seems simple enough. Hey, that's the same as the AC/HP model too!

Did you use Ester Oil on the fittings before torquing them?

[AC_Hacker]

Originally Posted by Xringer

Is this gauge any good?

Gauge 2" Vacuum Gauge 0-30"HG (0to -1 BAR) 1/8 NPT - eBay (item 180406066600 end time Oct-09-09 16:45:04 PDT)

When you pump the unit down, you'll be pulling a vacuum on the lines and the indoor unit. There's a fair amount of volume, and moisture could be there.

The gauge you picture is a bourdon gauge, and its accuracy falls off at the lower end of the gauge. It will tell you that the vacuum pump is working, but it will miss small leaks.

If you are going to let the tech do the pump down, it would probably be best to let him do the line set modification. It shouldn't take him more than 5 minutes to shorten the lines and make the flairs.

If you're gonna do the whole thing yourself, you should get some good tools and good gauges, including a manifold gauge and a micron gauge to test your equipment to make sure that your tools and techniques are all working properly.

You have an investment there, and the years of proper service you should expect from your equipment deserve your careful attention.

I hadn't finished the previous post, I have edited it to contain the info I started to write.

Originally Posted by Xringer

Hey, owning a vacuum pump might be useful for other stuff too.
And, like you said, I can always sell it..

I have no plans to let mine go...

Originally Posted by Xringer

I just read the manual for the AC only unit (borrowed from work) and it
said to vacuum down the lines to 10 mmHg abs, shut off the pump,
then release some R410A into the lines (for 10 seconds), shut it off
and then do a soap bubble test on all the fittings.

That seems simple enough. Hey, that's the same as the AC/HP model too!

Did you use Ester Oil on the fittings before torquing them?

Please see previous post

Best regards,

-AC_Hacker

[Xringer]

Don't have a welder yet. But Sears has the stuff for my wrench..

Sears.com

Just checked my 3/8 wrench against the big one and they match at
40 foot pounds. I think that's around the range I'll need.
But, I don't know what size I'll need yet.



Maybe I'll email the dealer and find out.. Bet it's 14mm..

[AC_Hacker]

Originally Posted by Xringer

According to what I've found, the COP is 3.4 when you are running it full bore.

29,000 BTUh, burning 2,490 watts gives you a 3.4 COP.
But, after things have warmed up and the unit is just coasting along at, say,
4,400 BTU, only burning 290 watts, you get a COP of 4.4

Maybe it's good this thing is a tad over-sided.?.

We have added a bunch of insulation in the past year, and I'm really looking
forward to seeing if I can actually heat my home using 290 watts!! LOL!!
At least on the mild days..

Hey Rich,

I built a small water-in, water-out heat pump and did various test, with this one being a good example: (full thread here)

The light blue line that jumps all over the place is the COP for the five minute period just measured. To make it fit on the graph, I multiplied COP time 10, so if it says that cop is 35, it's actually 3.5.

I'm not exactly sure why it's so jumpy, but there is a definite trendline that can be drawn through the COP values, that is very close to parallel to the temperature of the water coming into the system. Which makes sense when you think of it.

So, when as the outside air temperature gets colder, the COP of our Air-Source Heat Pumps will most surely, also decline.

So this all tells me that there's a point, when another system, like in you case, a hydronic heating system, will be cheaper to operate.

I don't know if you're set up to be able to measure the power that is being drawn by your heat pump, but it would be interesting to know that information.

Best Regards,

-AC_Hacker

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[Xringer]

I will be able to read 1 watt-hour flashes of the LCD on my meter.
But, I hope not to be standing outdoors when the temp drops to 12 deg F..

Anyways, during heating, max power used is ~ 2.5KW, and that's only good for 8530 BTU
if I used simple space heaters. I would be turning on the oil burner for sure!


I've heard that Sanyo has under-rated this unit and it will put out full heat all the way
down to 17 degs F. That's 29,000 BTU.. They also say it's 70% efficient at Zero degs F.
If true, that means at Zero, I'll should see 20,300 BTUh of heat!
The actual Sanyo spec says 16,200 BTU at Zero and 22,000 at 17 deg F...

I'm pretty sure that even in the coldest days, I'll be able to get at least
double what a simple space heater can give me for 2.5KW..

Best of all, it hardly ever gets really cold around here.. Too close to the sea I guess.

[Xringer]

When I look at a flare connection, I'm wondering what would be the best
way to test for a leak.?. A vacuum inside the tubing or pressure inside the line-set tubing?

With the shape of outer skirt of the flare, it seems like a vacuum would hold the tube tighter onto the tapered connector.

Whereas 200 PSI of nitrogen inside the line-set would be trying to force
the copper tube off the connector. (kinda like a one-way-valve).

And, nitrogen & 200 PSI gauges are cheap and easy to find.
If it held for a few days, that seems like it would be a pretty good test.

Comments please..

Thanks,
Rich

[AC_Hacker]

Originally Posted by Xringer

When I look at a flare connection, I'm wondering what would be the best
way to test for a leak.?. A vacuum inside the tubing or pressure inside the line-set tubing?

With the shape of outer skirt of the flare, it seems like a vacuum would hold the tube tighter onto the tapered connector.

Whereas 200 PSI of nitrogen inside the line-set would be trying to force
the copper tube off the connector. (kinda like a one-way-valve).

And, nitrogen & 200 PSI gauges are cheap and easy to find.
If it held for a few days, that seems like it would be a pretty good test.

Comments please..

Thanks,
Rich

Rich,

What you're saying does seem reasonable, and pressure probably would be a better test.

But there's an even better reason to pressurize with nitrogen, the dilution principle...

If you pulled a vacuum on the line set & inside unit first, you would be drawing out almost all of the air and water vapor. If you then introduced pressurized nitrogen into the vacuumed system, you would be introducing a very large amount of dry nitrogen into a volume which still contained a small amount of air and water vapor, This remaining air & water vapor would uniformly disperse itself amongst the nitrogen. After testing for leaks, you would need to pump it down again, to draw out the nitrogen and with it would come all but a truly infinitesimal amount of air and water vapor.

Then you'd be off to a really good start...

Regards,

-AC_Hacker

[Xringer]

I spoke to the tech guy today and we discussed leak testing and he agreed that using nitrogen worked better.
I theorized that under a vacuum, you could completely remove the flare nuts
and it might still hold a good vacuum..

The dilution principle makes pressure testing even better looking..
He also recommended the MasterCool 3 CFM vac pump. Said it had a check-valve.

Anyways, I'm wondering what type and size of flare nuts I'm going to see
on these 5/8" & 1/4" OD lines? Metric or regular?

[AC_Hacker]

Originally Posted by Xringer

[The Technician] also recommended the MasterCool 3 CFM vac pump. Said it had a check-valve.

I was gonna recommend a cheaper alternative, but I just looked online and they were about $100, so go for it.

Originally Posted by Xringer

Anyways, I'm wondering what type and size of flare nuts I'm going to see
on these 5/8" & 1/4" OD lines? Metric or regular?

Your unit may use different fittings than mine, just wait until your stuff arrives and measure it at that time.

You do know that you should use a tubing cutter that uses tiny knife-sharp wheels to do the jub, right? You don't want to use a saw and leave bits of copper to float about in your system.

Your tubes will also have lengths of foam insulation that you'll need to shorten. You can slide the insulation over the end of the tube and make your cut with scissors, then snug the end down to the tube with nylon tie-wraps.

Your tubing will have little plastic caps that keep dirt out of the tubes. The tube is not pressurized or 'filled' or anything. After you cut your tube and slip your flare nut (use the ones that are already on the tube) over the tube, then make the flare.

Then put the little caps back on the tube until you're ready to do the deed.

Regards,

-AC_Hacker

[Xringer]

Originally Posted by AC_Hacker

Good luck with your new unit.

I bought a 9,000 BTU version (12,000 BTU heating) of the Sanyo last year, to carry me through my GSHP project.

-AC_Hacker

How about giving us a little review on it's cold weather operation?
I'm interested in hearing how well it worked in the 20 to 40 degree range.
Since that's what we see around here on a typical winters day..