Heat Pump System and Portable Generator

 
Thread Tools Search this Thread Display Modes
Old 04-08-2013, 01:06 AM   #1
Junior Member
 
Spin's Avatar
 
Trade: Electrician
Join Date: Apr 2013
Location: Tacoma, WA
Posts: 2
Default

Heat Pump System and Portable Generator


I have a potential customer who asked me to install a transfer switch for her. She already has a 5000 Watt generator and I told her she will not be able run her heat with that. She has a heat pump system. (I don't know the exact size of her heat at this moment but, let's say there are two breakers for her heating unit, one a 50A/240V and another a 40A/240V; this is probably pretty close to what it actually is. She also has a heat pump, if I am not mistaken; probably a 30A/240V breaker for that. Do you have to run that also? Or, can you power only the furnace? Can you use the emergency heat setting on the thermostat without damaging the system and leave the heat pump itself off the generator?) I am wondering how to properly size a generator that will handle her heat and maybe four of five more circuits. I really want to recommend something that she will be happy with. Any help will be greatly appreciated.

Spin is offline  
Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. HVACSite.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Old 04-10-2013, 10:22 PM   #2
Senior Member
 
beenthere's Avatar
 
Trade: Service/Installation
Join Date: May 2009
Posts: 857
Default

Re: Heat Pump System and Portable Generator


Most likely, just one stage of emergency heat will be 5000 watts.

If she wants to heat her home to normal comfort temp, she will need some whee between a 15 to 25 KW generator.
__________________
How many times must one fix something before it is fixed?
beenthere is offline  
Old 04-14-2013, 12:26 AM   #3
Junior Member
 
Upton O Good's Avatar
 
Trade: High power engineering
Join Date: Apr 2013
Location: Claremont, CA
Posts: 6
Default

Re: Heat Pump System and Portable Generator


I'm no expert in this area, but I know a little about generators. Getting the right size can be difficult, even with experience.

Suppose you wanted to power a 50A/240 line. First you have to know the real continuous power required. The number on the brass plate is often only the MCA or MOC, while the actual current draw is considerably less. That works in your favor. On the other hand, the initial current surge is often much higher, and it sometimes last long enough to stall the generator. Related but uniquely different is the generator's ability to withstand a transient load. Some manufacturers may add a flywheel or other features to help, for example.

Bottom line: I would definitely call the manufacturer of any generator you are considering, and check with their applications engineer. Give them the whole scenario and get their input. You might be surprised how BIG the genny needs to be to really work well in that situation.

Lastly, you might consider renting a 25 kW dummy load and taking it to the generator seller. Hook it up and prove it out before buying. I've done it before for a 100 kW diesel. Sometimes its the only way to really know, as not all behaviors show up in the datasheet. A reputable seller wont mind a test. And the load is not big or heavy. One guy can move it.

--Upton O Good
Upton O Good is offline  

Tags
generator, heat, portable, pump, system


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
What size is this heat pump? hvac2010 Residential HVAC Forum 0 05-30-2012 06:31 PM
need help with heil heat pump elite Residential HVAC Forum 19 10-05-2010 04:23 PM
Heat Pump Defrost cmr_3168 Residential HVAC Forum 0 01-25-2010 10:00 AM
Heat Pump with Economizer NoTime General HVAC Discussion 3 01-23-2010 02:16 PM
heil heat pump 10 yrs old J. R . Smith General HVAC Discussion 1 06-17-2009 09:08 PM

Join Now... It's Fast and FREE!

I am a professional contractor
I am a DIY Homeowner
Drywall Talk is for
PROFESSIONAL CONTRACTORS ONLY!

At DrywallTalk.com we cater exlusivly to professional contractors who make their living as a contractor. Knowing that many homeowners and DIYers are looking for a community to call home, we've created www.DIYChatroom.com DIY Chatroom is full of helpful advices and perfect for DIY homeowners.

Redirecing in 10 seconds
No Thanks
terms of service

Already Have an Account?


SEO by vBSEO 3.6.1