ASHP operation in cold wet weather

Xringer · 10-30-11, 10:35 AM

Last night during all the rain and snow, Sanyo #1 was doing a lot of heating.
Before midnight, it started doing defrost cycles.
My automatic circuit breaker kicked in a couple of times while I was watching.

Since Sanyo #2 is in the Den, and doing less work. I never saw it defrost.
When I check it's coil this morning, there was about 15% icing on the bottom.
Not a problem, since heat out-put vs power used seemed normal for the conditions.
(Snow, rain @ 33F most of the night).

But, when I checked Sanyo #1, it's coil was 90% plugged with ice!
I'm amazed it was still giving us heat.. I knew it was using extra power,
but I did not expect to see so much ice. It was between just about every fin on the coil.

I don't think it had run in Defrost mode since last night.

So, to get better efficiency, I needed to remove that ice!
The living room was about 22C, so I decided to cool it off to 18C..
It's amazing how little power you need to cool off your house,
when it's 38 outdoors!
Ran it in cool mode for about 10 minutes and let it sit for 30 more.
Checked the coil.. 98% clear! Hardly any ice at all.

Both Sanyo systems are keeping us at 22C right now, with much better
(per-snowstorm) efficiency. 450w each at this second.

AC_Hacker · 10-30-11, 11:19 PM

Quote:

Originally Posted by Xringer

So, to get better efficiency, I needed to remove that ice!

Ran it in cool mode for about 10 minutes and let it sit for 30 more.
Checked the coil.. 98% clear! Hardly any ice at all.

Something is definitely not right here.

I have kept an eye on my little Sanyo, and I may get some ice build-up but it seldom reaches up more than a few inches into the evaporator fins, then the machine does a brief de-frost cycle (a few minutes at the most) and the frost is all gone. And here in Portland, it is reliably wet all winter long, save the occational freeze, when things get dryer.

There is a possibility that your de-frost circuitry is not working right, there is also the possibility that your main Sanyo is undersized to heat your house.

As I recall, you never did anything to quantify your heat load.

I would think that if you let your two heat pumps equally share the load (may require a few strategically placed fans), it would tell you something... If Sanyo#1 stops the over-current and de-frost failures you have repeatedly had, it would point to the probability that you had undersized the Sanyo#1... If Sanyo#1 continues it's problems, either you have a lemon or it's possibly a poor design.

Doubling your available heat output should make a dramatic difference.

* * *

I must say that if Sanyo has any idea how much trouble you have had, and how publicly you have detailed this trouble, that they would dispatch a team of engineering specialists straightaway to you house and keep them there working on your heat pumps until they were working faultlessly.

It would only make good business sense.

-AC_Hacker

Xringer · 10-31-11, 09:53 AM

Woburn, Massachusetts (MA) profile:
Portland, Oregon (OR) profile:

If your daily low average was under freezing, comparing defrost cycles would be more meaningful.

You might be right about a defrost problem with #1. It could be the sensors.
I have done some comparisons (between the two systems) of the thermistors.
But, I have not checked all of them.. And none in the indoor units.
I'll do it some day when the weather is nice, since I need to turn off
both systems and let their temps stabilize, before taking resistance readings.

After working for a Japanese company(NEC) for 18 years, I kinda understand why Sanyo US has little interest in the problems with my system. Maybe if I put it on Youtube??

I have been in contact with Sanyo US, and have gotten some suggestions for trouble shooting.
One idea was to have the R410A pulled and weighted.

IMHO, the firmware is NG, wrong chip maybe, or just poor programming.
Or maybe there is a too-long time lag before the thermistors feed back the changing heat value.?.

RKA · 11-10-11, 10:50 AM

Can you check the charge by means of superheat or subcooling? I'm finding info suggesting it's either impossible with mini splits or not recommended, but I can't seem to find out why. If it is possible that would avoid having to pull and weigh the charge.

Refrigerant Charge, Adding Freon to Heat Cool Unit |

Xringer · 11-10-11, 11:20 AM

It might be possible to do those tests, but when the electronically controlled TXV
is being adjusted by the system controller and the speed of the compressor motor,
and fans are also constantly being adjusted. The results might be hard to interpret.
I've heard these systems might be using some kind of "fuzzy logic" in their controllers..

I do have a plan to monitor both my Sanyo systems
http://ecorenovator.org/forum/applia...ontroller.html

By comparing their power use vs their input & output refrigerant temps,
I should be able to determine which system is working better..
The unit in the den, is low on refrigerant.
Theoretically, it should not work as well.. We'll have to wait and see.

RKA · 11-10-11, 02:51 PM

I hadn't thought about that, but now that you mention it, I would think they would have some kind of service mode that would run heat/cool at full blast just for this purpose. Might be worth asking next time you have them on the phone.

I've seen instructions that tell you to adjust the charge not only based on line length deltas but also based on the number of tight radius turns. It just seems silly to me that they can't design these systems to be dialed in by subcooling and superheat.

Xringer · 11-10-11, 03:20 PM

There is a test mode. (T-Run) I used it during the repair & test process.
http://ecorenovator.org/forum/geothe...r-project.html
In cooling mode, it seems to run at a nice constant clip, (using about 5.5amps)
but in heating mode it tries to run at 160%, so I didn't even try to use it.

I was thinking of trying to use the repaired unit as a hot water heater, just running it in T-Run.
But, since T-Run does badly in heating mode.. Not really usable.
If I was using it for cooling stuff off to -20 F, it would have been great!

I even considered putting the unit in my basement (for space heating)
and sticking a new DIY coil and fan unit outdoors..To suck in some heat!

It was a flip of the coin (and my wife likes a warm Den) that we ended
up buying a new indoor unit.. It wasn't too expensive..
http://ecorenovator.org/forum/geothe...ct-2011-a.html

10-31-11, 09:53 AM	#3
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Portland vs Woburn Woburn, Massachusetts (MA) profile: Portland, Oregon (OR) profile: If your daily low average was under freezing, comparing defrost cycles would be more meaningful. You might be right about a defrost problem with #1. It could be the sensors. I have done some comparisons (between the two systems) of the thermistors. But, I have not checked all of them.. And none in the indoor units. I'll do it some day when the weather is nice, since I need to turn off both systems and let their temps stabilize, before taking resistance readings. After working for a Japanese company(NEC) for 18 years, I kinda understand why Sanyo US has little interest in the problems with my system. Maybe if I put it on Youtube?? I have been in contact with Sanyo US, and have gotten some suggestions for trouble shooting. One idea was to have the R410A pulled and weighted. IMHO, the firmware is NG, wrong chip maybe, or just poor programming. Or maybe there is a too-long time lag before the thermistors feed back the changing heat value.?. Last edited by Xringer; 10-31-11 at 01:43 PM.. Reason: Had to go out for a while..

11-10-11, 11:20 AM	#5
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	It might be possible to do those tests, but when the electronically controlled TXV is being adjusted by the system controller and the speed of the compressor motor, and fans are also constantly being adjusted. The results might be hard to interpret. I've heard these systems might be using some kind of "fuzzy logic" in their controllers.. I do have a plan to monitor both my Sanyo systems http://ecorenovator.org/forum/applia...ontroller.html By comparing their power use vs their input & output refrigerant temps, I should be able to determine which system is working better.. The unit in the den, is low on refrigerant. Theoretically, it should not work as well.. We'll have to wait and see. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

11-10-11, 03:20 PM	#7
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	There is a test mode. (T-Run) I used it during the repair & test process. http://ecorenovator.org/forum/geothe...r-project.html In cooling mode, it seems to run at a nice constant clip, (using about 5.5amps) but in heating mode it tries to run at 160%, so I didn't even try to use it. I was thinking of trying to use the repaired unit as a hot water heater, just running it in T-Run. But, since T-Run does badly in heating mode.. Not really usable. If I was using it for cooling stuff off to -20 F, it would have been great! I even considered putting the unit in my basement (for space heating) and sticking a new DIY coil and fan unit outdoors..To suck in some heat! It was a flip of the coin (and my wife likes a warm Den) that we ended up buying a new indoor unit.. It wasn't too expensive.. http://ecorenovator.org/forum/geothe...ct-2011-a.html __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

10-30-11, 10:35 AM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	ASHP operation in cold wet weather Last night during all the rain and snow, Sanyo #1 was doing a lot of heating. Before midnight, it started doing defrost cycles. My automatic circuit breaker kicked in a couple of times while I was watching. Since Sanyo #2 is in the Den, and doing less work. I never saw it defrost. When I check it's coil this morning, there was about 15% icing on the bottom. Not a problem, since heat out-put vs power used seemed normal for the conditions. (Snow, rain @ 33F most of the night). But, when I checked Sanyo #1, it's coil was 90% plugged with ice! I'm amazed it was still giving us heat.. I knew it was using extra power, but I did not expect to see so much ice. It was between just about every fin on the coil. I don't think it had run in Defrost mode since last night. So, to get better efficiency, I needed to remove that ice! The living room was about 22C, so I decided to cool it off to 18C.. It's amazing how little power you need to cool off your house, when it's 38 outdoors! Ran it in cool mode for about 10 minutes and let it sit for 30 more. Checked the coil.. 98% clear! Hardly any ice at all. Both Sanyo systems are keeping us at 22C right now, with much better (per-snowstorm) efficiency. 450w each at this second.

11-10-11, 10:50 AM	#4
RKA Lurking Renovator Join Date: Sep 2011 Location: NJ Posts: 27 Thanks: 0 Thanked 1 Time in 1 Post	Can you check the charge by means of superheat or subcooling? I'm finding info suggesting it's either impossible with mini splits or not recommended, but I can't seem to find out why. If it is possible that would avoid having to pull and weigh the charge. Refrigerant Charge, Adding Freon to Heat Cool Unit \|

11-10-11, 02:51 PM	#6
RKA Lurking Renovator Join Date: Sep 2011 Location: NJ Posts: 27 Thanks: 0 Thanked 1 Time in 1 Post	I hadn't thought about that, but now that you mention it, I would think they would have some kind of service mode that would run heat/cool at full blast just for this purpose. Might be worth asking next time you have them on the phone. I've seen instructions that tell you to adjust the charge not only based on line length deltas but also based on the number of tight radius turns. It just seems silly to me that they can't design these systems to be dialed in by subcooling and superheat.