Forums | Home Repair | Home Improvement | Painting | Interior Decorating | Remodeling | Landscaping


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 10-23-2011, 11:20 AM   #1
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Share |
Default

Defrost mode on heat pump.


My heat pump is set to defrost cycle at 90 minute intervals. I recently noticed that the defrost came on when the temperature was 59. This does not seem right at that temperature. At what temperature should the system be in for a call for defrost mode. What would cause this?
roku is offline   Reply With Quote
Old 10-23-2011, 11:28 AM   #2
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


do to your control being a timed defrost control board it will defrost at 90 min run time no matter what the outdoor temp is.
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 11:38 AM   #3
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Default

Defrost mode on heat pump.


If this is the case. I'd like to manually control when the auxiliary heat strips come on in defrost mode. It seems ridiculous to have them come at say 50 or even 40. I know I can disconnect the wire that engages the heat strips while in defrost mode. Is there a switch I can use so I would not have to physically disconnect said wire?
roku is offline   Reply With Quote
Old 10-23-2011, 11:54 AM   #4
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


yes, a switch could be used at the air handler that would break the circuit for the strips from the heat pump, but while the unit is in defrost it will be putting cold air in the home then.
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 12:05 PM   #5
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Default

Defrost mode on heat pump.


I fully understand that. But I am thinking more on cost savings at those temps as compared to dealing with cool air during the defrost mode. I can tinker with it to see what temp I can withstand without the auxiliary heat strips coming on. What type of switch can I use to make this happen?
roku is offline   Reply With Quote
Old 10-23-2011, 12:17 PM   #6
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


honestly just about any switch will work. spst.... a light switch would work or something from a auto parts store would work as well. It's not going to pull more than 1 amp through the switch. All you are doing is opening and closing a circuit.
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 12:23 PM   #7
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Default

Defrost mode on heat pump.


Would I not need a switch specific for that of a thermostat wire? Not sure but I think it is 24vac for the wire.
roku is offline   Reply With Quote
Old 10-23-2011, 12:24 PM   #8
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


yes, 24vac.... so anything rated for that or higher voltage will work
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 12:28 PM   #9
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Default

Defrost mode on heat pump.


Do they sell a 24vac switch in auto parts stores? Having trouble finding one online.
roku is offline   Reply With Quote
Old 10-23-2011, 12:38 PM   #10
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


not specifically for 24VAC... if you are not sure then go to the hardware store and buy a 2 X 4 metal box, light switch, and cover.
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 12:52 PM   #11
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

Defrost mode on heat pump.


There should be a defrost sensor on your heat pump that starts the timer when the line temp is 28-30 degrees. When the line temp stays above that then the timer is not activated but the board will initiate a defrost after 6 hours of run time no matter what the temp for oil return to the compressor. Low on charge, dirty coils,a weak capacitor or a dragging motor can all cause frost to form too soon resulting in excessive defrost cycles. If there wasn't frost then it could have just been the oil return cycle time.
Marty S. is offline   Reply With Quote
Old 10-23-2011, 12:58 PM   #12
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


Quote:
Originally Posted by Marty S. View Post
There should be a defrost sensor on your heat pump that starts the timer when the line temp is 28-30 degrees. When the line temp stays above that then the timer is not activated but the board will initiate a defrost after 6 hours of run time no matter what the temp for oil return to the compressor. Low on charge, dirty coils,a weak capacitor or a dragging motor can all cause frost to form too soon resulting in excessive defrost cycles. If there wasn't frost then it could have just been the oil return cycle time.

they do not all have that sensor
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by hvactech126; 10-23-2011 at 01:15 PM.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 01:01 PM   #13
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Default

Defrost mode on heat pump.


So are you saying that I can use a basic single pole switch for this? If so, is this how to wire it? Wire from airhandler hooked to top of switch and wire to heat pump condenser hooked up at the bottom of switch.
roku is offline   Reply With Quote
Old 10-23-2011, 01:15 PM   #14
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Defrost mode on heat pump.


yes, basic single pole switch. From W2 of defrost control to switch. From switch to heat element terminal in air handler.
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is offline   Reply With Quote
Old 10-23-2011, 02:05 PM   #15
Newbie
 
Join Date: Oct 2011
Location: Emporia, Va.
Posts: 7
Default

Defrost mode on heat pump.


"From W2 of defrost control to switch" Is this wired to the top of switch?

"From switch to heat element terminal in air handler" Is this wired to the bottom of switch?

Would the wire from the defrost control board be considered the power source?
roku is offline   Reply With Quote
Reply


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
Using Gas heat during Defrost mgroves HVAC 15 12-18-2010 05:51 PM
New Heat Pump Problems Cooling Zombify HVAC 2 04-06-2010 03:42 PM
Hot Water Recovery- Heat Pump A/C mode AndrewF HVAC 1 03-05-2009 05:04 AM
Heat Pump set back GEAF HVAC 6 01-26-2009 07:49 AM
Heat Pump vs Aux Electric Heat batolson HVAC 16 01-17-2009 10:28 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.