Heat Pump with backup generator


Hi all,
I have a Lennox 2.5 ton heat pump along with a CBX32M air handler. What i'd like to do is install a backup generator. A pretty large one (22KW) but not large enough to power the heating system with the electric backup heat which is 15KW in itself.
Can I just wire the compressor, and the air handler itself through the transfer panel to get basic heat/cooling without the electric backup heat? My theory being that it should be sufficient as long as its not very cold outside. if that happens, then we can add space heaters via plugin.
If that is possible, I think my problem is that the blower motor in the air handler is wired in with the electric backup elements. Is there a way to separate the blower and perhaps put it on the compressor circuit instead, so that I can power that through by transfer switch panel on a fairly modest ampacity circuit (about 15A for compressor and 1.7A for the blower)?
Thanks!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 9/7/2010 6:28 PM, snipped-for-privacy@gmail.com wrote:

I've setup systems like that in the past and the best way to do it is through the control system. The way I would do it is have a relay with normally closed contacts that will break the control circuit for the heating element contactor whenever the generator is running. It's not rocket surgery but you need to understand control circuits.
TDD
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sigh. More spam from Gmail.
--
Christopher A. Young
Learn more about Jesus
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That really wouldn't work for me because that forces me to run the entire electric heating circuit through the transfer switch, and its limited to 100A.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Simply interrupt the control side of the strip heat ( IOW the 24 VAC control to it ) with a small relay with a 120VAC coil, use a NO contact, and power that coil as 'always on' from a non-transferred circuit.
On Mon, 13 Sep 2010 04:41:56 -0700 (PDT), " snipped-for-privacy@gmail.com"

--
Click here every day to feed an animal that needs you today !!!
www.theanimalrescuesite.com/
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 9/13/2010 6:41 AM, snipped-for-privacy@gmail.com wrote:

Well duh! < me. It can be separated inside the unit without too much trouble. The darn heat strips and air handler will draw more than 65amps alone at 230VAC. The diagram I found online shows what would have to be split off. I would install a control relay to lockout the heat strips to prevent any possibility of power back feeding through the system via the electric heat relays when the main power goes out.
http://www.innovation-group.com.ua/downloads/ii/ah/505342b.pdf
If you wanted to get a bit fancy, you can install a latching contactor of the type used in many transfer switches and lighting controls that will stay on until getting a signal from your transfer switch to open the circuit to the heat strips. You may have a more detailed wiring diagram that came with your unit than the one I found online. Of course, when splitting the power, pay attention to the phases and make darn sure BOTH power sources are disconnected when any work is done on the air handler.
TDD

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

For a 2 1/2 ton heat pump, you don'g need 15kw strips in the first place. All you need is 10kw. Also remember that in heating mode you will have defrost cycles that will be running both the compressor and the strips at the same time.
FWIW, those plug it in the wall heaters average 5kw each. That defeats the purpose.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 9/8/2010 7:16 AM, Steve wrote:

Time for him to install gas logs and a propane tank. Of course, I wonder what fuel the generator is running on. I remember back in the middle of the last century when all electric homes in this area were considered to be the cleanest and most economical to heat. 8-)
TDD
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Clean electric. What a hoot. Just means that the pollution is some where else, in the power grid. Back in the seventies, my area got a nuclear power plant. Which is fine with me. They were talking about how clean the power is. Cleaner than coal, I'm sure. Just hope they figure out what to do with the radioactive stuff after it's used.
An example of non polluting clean power. Is to go to the woods and set up a gasoline generator, run a couple hundred feet of cord. The point of use has no pollution.
--
Christopher A. Young
Learn more about Jesus
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Where do I get a couple of those? The space heaters I've seen here run 1500 watts, and put out 5,200 BTU per hour.
--
Christopher A. Young
Learn more about Jesus
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I saw one blowing over the wet floor at the airport. Of course it was using 277V.
Ah, can't find that one, but:
http://www.tombling.com/heaters /
has lots of high output, portable units.
You _do_ have 440 service to your living room, right?
--
_____________________________________________________
Knowledge may be power, but communications is the key
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Only via local step up transformer.
I wonder why anyone would make such a large filament heater. No fossil fuels avaialble, maybe?
--
Christopher A. Young
Learn more about Jesus
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

120 volt, 5,000 watt, plug in wall heaters? You running 120 volt, 50 amp circuits to run those heaters? Plug in heaters run 1500-1800 watts. Greg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

My bad.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Most of the space heaters I've seen sold, are 5,000 BTU.
--
Christopher A. Young
Learn more about Jesus
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Which works out to about 1500 watt. Greg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

    Don't confuse the boy.
    Oops ! Too late ......
--
Click here every day to feed an animal that needs you today !!!
www.theanimalrescuesite.com/
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 11 Sep 2010 12:21:25 -0400, .p.jm.@see_my_sig_for_address.com wrote:

The mormon school of hvac says one watt per btu. Don't you know nothing?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.