You have 1 to two transformers on. You could measure amp draw to those for your answer.
joe

I have a Climatemaster Tranquility 27 6 Ton system. When the system is not running it consumes 40 watts AC.

Almost forgot, that 40 watts also includes a seperate zone control board.  So the heat pump would be a less then 40 watts.

Thanks! I'm trying to get a handle on phantom loads...can't believe how much things add up to! I'd like to try and get my daily "always on" down to 100 watts or less. I can't believe things like all my routers/FIOS/printer/hub/UPC adds up to 60 watts all the time.
Any harm on these beautiful fall days of just shutting the circuit breakers off on the Geo?

I have a Hydron 3 ton unit.  I have a meter on my circut panel to measure electric use.  The "phantom" laod on my unit when not running averages 24 watts.  Sometimes it dips as low as 12 watts

Posted By stuart.wyss on 01 Oct 2010 02:41 PM
Any harm on these beautiful fall days of just shutting the circuit breakers off on the Geo?

No....but: thermostats on battery backup are recharged when circuit is open. They discharge during calls for heat or cool and when system is off. thermostats without battery back up, have a more expensive back up battery that will discharge when unit is shut down.
j

I didn't know that stats could recharge batteries following a power outage. The Honeywells I put in all come with Alkaline batteries, and I know recharging them is a bad idea. Do some thermostats have a selection or feature to activate a trickle charge into batteries if rechargeables are used?

I'm looking for high-end HVAC manufacturers to come out of the Stone Age regarding control power transformers. The present models run hot and have fairly high standby load as previous posters have noted. I believe there is or will soon be a standard for transformers for small appliances to consume less than 1 Watt on standby - seems the same technology ought to be applicable to control power transformers.

I thought there were some thermostats that had a "supercap" of some sort that would charge during power-on, and carried enough juice to hold the thermostat through some number of hours of power failure...if not, someone should invent one!

An ideal system might be thermostats that have their own extra low wattage transformer, and when off (either manually off or during times of no call for heating/cooling) could turn off the HVAC main power supply/transformers. Maybe I can use a pair of unused thermostat wires to supply 5 volts from a basement 1 watt wall-wart to each of my thermostats (the battery backup in each is 3 AA batteries). Then somehow rig a high-power relay to any call for heat/cooling and connect the main power line from the Geo.

Hmmm, although at times when the system is cycling on/off to maintain temp, perhaps starting up/shutting down all the electronics would be bad.

Maybe just a "master power" switch to shut off all the electronics at the top of the basement stairs or something, like an oil-burner cut-off switch.

Then, a pair of unused thermostat wires delivering 6 volts @ 500mA to each thermostat from an ultra-low power wall-wart. On all those spring/fall days when you don't even need the system on, you could shut it off conveniently at the top of the stairs, but know that your thermostats won't be running on batteries.

What do thermostats run on? 24 VAC regulated in the thermostat down to 5 VDC or something?

Control power (24 VAC) powers theromostats. Batteries back up ther thermostat's programming. Going out on a limb, I suspect that the relays within a thermostat that switch on the various outputs are also control voltage powered - the batteries don't drive them. There's no point in firing a relay directing 24 volts down a conductor if the 24 volts aren't there in the first place.

Given the use of 2-3 1.5 volt batteries in a typical stat, I imagine the memory electronics are comprised of some sort of low voltage DC CMOS or successor solid state technology. The days of 5 volt TTL logic are long past

I'm way out on a limb here, so don't bank on the foregoing.

From the Honeywell VisionPro IAQ Owners Manual:

"This thermostat contains a Lithium battery which may contain Perchlorate material.
Special handling may apply, see www.dtsc.ca.gov/hazardouswaste/perchlorate."


IIRC, that means that it shouldn't be installed on a nuclear submarine.

Beware difference between straight Lithium batteries (very long shelf life but not rechargeable) and Lithium-Ion batteries (state of the art rechargeable)

Posted By engineer on 04 Oct 2010 08:42 AM
Control power (24 VAC) powers theromostats. Batteries back up ther thermostat's programming. Going out on a limb, I suspect that the relays within a thermostat that switch on the various outputs are also control voltage powered - the batteries don't drive them.

I'm way out on a limb here, so don't bank on the foregoing.

When I pre-program the Honeywell 8000 stats with battery backup for customers in the evening while relaxing in my chair, going thru the various cycles I can hear the thermostat click when it changes modes. At least with that model the 24V is optional and the 24V drives the optional night light and makes the battery last longer.

Posted By joe.ami on 01 Oct 2010 10:17 PM

No....but: thermostats on battery backup are recharged when circuit is open. They discharge during calls for heat or cool and when system is off. thermostats without battery back up, have a more expensive back up battery that will discharge when unit is shut down.
j

I had an issue with my ASHP this summer, the system failed to turn on one day making it very hot upstairs. I reset the system and it worked fine for a week, then one night the system never turned off, it was 60 degree upstairs. Replacing the batteries resolved the issue, so I guess the way it's wired, the thermostat is running off batteries all the time. Anyway it was several years between the time the batteries were replaced and the system failed to work right. So turning the entire system off of what will amount to a few weeks at best, I wouldn't expect the batteries to discharge enough to affect it when you turn it back on. 

Tex,

Thanks for that observation - I was clearly mistaken about the source of relay power. I'll have to remember your technique heading into 5 8000 series stats I need to program next week.

Posted By stuart.wuss on 01 Oct 2010 11:08 AM

Can anyone give me an approximate "phantom" power for their Geo unit?  I'm curious about the wattage when the system is off.  The thermostats, zoning panel, and electronics are all still on, using power.  I'm unable to plug the Geo into a Kill-A-Watt :-)

Thanks!

My units, total (two - WaterFurnace Envision 3 and 5 ton 2-stage), in standby, are combined consuming 42 watts.  That's with the reversing valve in Cool mode.  So that's about 21 watts per unit.

Looking at a log monthly file for this past Jan., when my tstats were holding the reversing valves in Heat mode, standby power was 29 watts, or approximately 15 watts per unit.

I have a Web Energy Logger (WEL) monitoring system with high frequency power transducers.  One of my power transducers is dedicated just to accurately measuring HVAC associated energy usage, with a measurement resolution at +/- 1 watt.  Here in the Dallas area neither heating nor cooling are needed at the moment, and thus you can easily see now what the standby wattage is of my geothermal units at http://www.welserver.com/WEL0043 (upper left corner, labeled "HVAC Now.")

Hope this helps.

Best regards,

Bill - WEL0043

I've been tinkering with a TED 5000 monitoring system this week and have learned, among other things, that my WF Envision 038 consumes about 20 Watts in standby; that's in reasonable agreement with Bill's data.