Heater Defrost Balance Point

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Will we ever know if the HVAC guy is telling the truth?
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Christopher A. Young
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About twenty years ago, my sister lived in apartment. Shared the second floor of a rental house. The other tenant had the thermostat. He'd turn it way down, and go to work. She and her boyfriend would freeze butt all day.
Earl Proulx has done something similar. The "Yankee home handyman". He has put a non functioning stat for the old folks to fiddle.
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Christopher A. Young
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Begining to sound as like you all assume I'm not to swift. Let me give you 1 of many reasons I don't care for the decision process of the thermostat using it's default settings.
Had therm set overnight at 68. Next morning the outdoor temp was ~ 55. Reset therm to 74. 2nd stage HP heat came on and was doing a reasonalbe job bringing up the indoor temp. At some point therm decided to it was taking too long and switched to gas heat. At that outdoor temp and with the gas vs electric rates in my situation, the gas heat was ~ 5X as expensive as HP heat. I've since disabled the time-out timer that mindlessly switched to gas. Now the only time it will auto switch to gas is if the outdoor balance point is reached or if I decide I'm willing to pay higher month cost to more quickly reach the indoor set point.
I'm a professional engineer who understands this stuff. In my old system I just put a toggle swich on W2, but there's no W2 (or W1, Y1, or Y2)on these data-link systems so I need to learn this new (to me) config terminology.
Hope this helps understand where I'm coming from.
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On 10/16/2010 10:48 PM, M Harris wrote:

I now understand what it is you want to do and why. The only problem is that you no longer have a simple relay logic control system. The only thing to do is hack the system or discover the insider secrets to programming your gear which may only be available to dealers and company engineers. I wonder, does your system have any kind of remote communication capability? When me and an electrical engineer friend were installing HVAC control systems in some new schools some years ago, the systems were tied together to a central point and accessed remotely via a dial up modem. A system as modern as what you have must surely have an Ethernet connection somewhere or at least a serial interface.
Perhaps if you could rig a computer interface, you could write your own control software. I have no idea what communication protocols your system is using. Heck, it all used to be RS232, 422, 485 and a few other serial types. Now there's some stuff I've never seen and have no clue as to how it works. I think what you would really like is a smart home interface with your HVAC system. I would be a lot of fun to pull it up on the computer and control it in real time.
TDD
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The 'auto discovery mode' on these new systems is like 'plug & play' on a PC. While most installers are content to let the system set itself up, the installer manual actually allows quite a few configuration parameters that can be set in the 'installer mode'. For now I'm content to just figure out what they all mean, which is what lead to the "Compressor Cycles Per Hour" question. Choice is 2-6 (default is 3) Most likely it means what it says but what is the 'intent' of the setting. It's a new term to me.
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On 10/17/2010 5:04 AM, M Harris wrote:

I haven't installed any systems like what you have because me and my buddy don't have a customer base that can afford the latest super duper with all the bells and whistles systems. The closest I come to complicated controls is in the mini split systems. We have a friend who is a Standard and Trane dealer and I'm sure he has sold brainy systems like yours but he's not going to play with the parameters unless he's on the phone with the factory tech support.
I'm going to make a SWAG that the CCPH will also affect compressor run time in a way that the system will overshoot the cut off set point more with the fewer number of compressor cycles. It's similar to what I do on refrigeration mechanical control systems using pressure switches. I'll set a wide differential for cut in and cut out to keep the compressor from cycling too often. The existence of product provides the needed hysteresis for the control cycle. It's what I often describe to people as a thermal flywheel to help them understand. Folks will turn the thermostat way up or down depending on the season thinking it's going to change the temperature inside their home faster. I tell them that the little lever is not like an accelerator peddle in a car and the HVAC system only has one speed (except for multi-stage) and it's not going to work any faster. I know there are new systems for homes that have variable speed drives for both compressor and air handling but those aren't the majority of systems in existence. In the future the whole dang house will be controlled by a computer but most of us will be gone by then and won't have to worry about it. You could even program the house loud speakers to blast out "YOU KIDS GET OFF MY LAWN!"
TDD
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" M Harris" <mh at soalex.us> wrote in message

So your telling us that it wasn't set up correctly in the first place.
The *ONLY* times the furnace should light off is when the balance point is reached, or the control is put into emergency heat mode. There is a propriatary cable and propriatary software (its not free) to be able to interigate and configure serial controled systems from a laptop.
FWIW, I don't even have it... At this time, its not worth it for me to buy the software and cable.
If you toggle on the intellegent recovery function, the control will use the most economical means of bringing the home from night time setback up to the daytime setpoint. The control is constantly learning when to bring the system on and in what mode to have your home at the desired setpoint at the desired time. Its going to do a whole lot differently at 55F than it will at 25F, but its going to do it in the most economical means possible. You can also toggle the setting for comfort or economical...this will help too.
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On 10/17/2010 7:33 AM, Steve wrote:

Do the high end systems you sell have remote management capability? I see it with a lot of other stuff I deal with but haven't worked with any home HVAC systems that have it. Remote management has become so inexpensive as of late that it's easy to add to just about anything. Heck, I think there has been an Internet ready refrigerator around for a while. I seem to recall seeing some IP addressable thermostats available but I haven't played with any, yet.
TDD
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I don't have the remote management capabilities with the system I install (yet), but all of the systems I install either have the VP-8000 control, or the IAQ control for dual fuel/hybrid systems. Even though the IAQ control has "auto-discovery", I choose to do it manually, as well as to spend the 10 - 15 minutes to do the setup and programming when I install them, as well as programming the customers comfort settings. But you gotta remember that I do things differently than "Bubba" or "Billy-Joe-Jim-Bob".
I figure I must be doing something right, 15 years and I am *still* in business(and making a profit), with a customer base of over 600(18% have service agreements).... not too bad for a one man band in rural, small town Mississippi.
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On 10/17/2010 9:02 AM, Steve wrote:

Congratulations on your success, I wish my health was better so I could take care of more people. I'm glad to hear that you take the time to do it right the first time. It's a shame more folks don't have the same work ethic and just throw the equipment in. I'm sure you come across a lot of situations that elicit a big WTF and the question of why on earth did those guys do that? Keep up the good work! 8-)
TDD
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Thanx.... I take pictures when I run across some really bad stuff, and make copies for the local county planning commission to give them ammo for getting inspections and code enforcement in place.
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Steve - I also would have expected that the *ONLY* times the furnace should light off is when the balance point is reached but it's not so. There's a theremostat parameter called Installer Setup Number (ISU) 0346. It's labled "Dual Fuel Heat Pump Upstage to Furnace Timer". The installer manual describes it as "System will switch to gas furnace to satisfy call for heat if timer expires" Factory default is 60 minutes. Since I disabled it, it stop switching over to gas.
I hope this helps clarify why it's in my best economic interest to better understand and take some control of the beast.
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On Mon, 18 Oct 2010 19:21:44 -0400, " M Harris" <mh at soalex.us> wrote:

And BTW, don't ever mention Pauls bald spot, ON, or OFF again!
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On 10/18/2010 7:15 PM, The King wrote:

ALL HAIL THE KING! 8-)
TDD
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