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 09-07-2010, 01:21 PM   #1
Member
 
Join Date: Jul 2009
Posts: 198
Rewards Points: 150
Default

Help with wiring onf HVAC system


Oh this one should get all the pros worried..

I am curious about signal wiring of the thermostat and most importantly the condenser. I have my 2, 120V contactor wires coming from the condenser but where in the air handler do they go? Also, there are some taps in the handler Marked, W, R, G, C, etc. I do NOT like to simply rely on color matching to wiring things. I wanna "know" how this thing is wired.

I do have the schematic for the system in my hand but does not indicate a voltage on half of the stuff and certainly does not include an output for the condenser coil contactor. Where does this power come from? There just does not seem to be enough wires to get this all done.

I guess maybe 3 is all that is needed? Request for heat, request for cool, common.... Maybe I am over complicating this..

viper is offline   Reply With Quote
Old 09-07-2010, 01:30 PM   #2
fabrk8r
 
fabrk8r's Avatar
 
Join Date: Feb 2010
Location: Iowa
Posts: 849
Rewards Points: 500
Default

Help with wiring onf HVAC system


Quote:
Originally Posted by viper View Post
there are some taps in the handler Marked, W, R, G, C, etc.
Those lugs are for the low voltage (24V) thermostat wiring. Does your schematic show the thermostat connections?

__________________
"The physician can bury his mistakes, but the architect can only advise his clients to plant vines." -- Frank Lloyd Wright
fabrk8r is offline   Reply With Quote
Old 09-07-2010, 01:39 PM   #3
Member
 
Join Date: Jul 2009
Posts: 198
Rewards Points: 150
Default

Help with wiring onf HVAC system


I do see where the Tstat wires in but reall does not tell me which is what so I guess going to have to go off what is here.

I still do not have any clue where the outputs are for the condenser. That should be a 120V source?? Looking at the wiring in the condenser, there is 2, 18ga-ish wires to the main contactor and wires led back to the air handler. (used system that I am reinstalling). Because this is a heat pump, the wiring is probably much more complicated that it should be and I still do not know how the heat pump system is initiated. Has to reverse the system somehow and 1ph motors do not like to reverse so I would assume some type of diverter valve in the condenser somewhere.
viper is offline   Reply With Quote
Old 09-07-2010, 01:49 PM   #4
Member
 
Join Date: Jul 2009
Posts: 198
Rewards Points: 150
Default

Help with wiring onf HVAC system


EDIT: after taking another peek, that latching coil in the condenser main contactor is actually 24V. I am looking at the wiring for it right now. Looks like there was probably supposed to be several wires to the blower unit to control the heat pump system and looks like that has already been bypassed because it was controlled with 2 wires. I can see where they are headed but just do not see what they should tie to in the air handler.
viper is offline   Reply With Quote
Old 09-07-2010, 02:37 PM   #5
fabrk8r
 
fabrk8r's Avatar
 
Join Date: Feb 2010
Location: Iowa
Posts: 849
Rewards Points: 500
Default

Help with wiring onf HVAC system


Condensing unit/heat pump should be 240V.

There will be a 110V reversing valve inside the condensing unit. You can usually see it if you look down through the fan. It will have 2 wires on it's quick connector that come out into the unit's access panel area.

Do you have 5 conductor thermostat wire from the air handler/furnace to the condensing unit?
__________________
"The physician can bury his mistakes, but the architect can only advise his clients to plant vines." -- Frank Lloyd Wright
fabrk8r is offline   Reply With Quote
Old 09-07-2010, 04:31 PM   #6
Member
 
Join Date: Jul 2009
Posts: 198
Rewards Points: 150
Default

Help with wiring onf HVAC system


Quote:
Originally Posted by fabrk8r View Post
Condensing unit/heat pump should be 240V.

Yes, I realize. The main power to the condenser is 240V. I am only referring to the signal wiring. ie, contactor relay.

There will be a 110V reversing valve inside the condensing unit. You can usually see it if you look down through the fan. It will have 2 wires on it's quick connector that come out into the unit's access panel area.

Do you have 5 conductor thermostat wire from the air handler/furnace to the condensing unit?
There is only 2 wires coming from the condenser and I can tell the heat pump side has been bypassed thus the 2 wires. there is 18/2 going from the condenser to the furnace. Just need to know where to get my 24V to turn on the condenser.
Please read above.
viper is offline   Reply With Quote
Old 09-07-2010, 05:37 PM   #7
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,580
Rewards Points: 2,840
Default

Help with wiring onf HVAC system


Quote:
Originally Posted by fabrk8r View Post
Condensing unit/heat pump should be 240V.

There will be a 110V reversing valve inside the condensing unit. You can usually see it if you look down through the fan. It will have 2 wires on it's quick connector that come out into the unit's access panel area.

Do you have 5 conductor thermostat wire from the air handler/furnace to the condensing unit?
Residential heat pumps don't use 120 volt reversing valves.
beenthere is online now   Reply With Quote
Old 09-07-2010, 06:41 PM   #8
Member
 
Join Date: Jul 2009
Posts: 198
Rewards Points: 150
Default

Help with wiring onf HVAC system


Yeah, it would have to be 24V or 240V because those are the only 2 voltages at the condenser. common is not carried to the condenser so 120V is not used.

viper 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
Openings in air intake duct on central HVAC system Omegazz HVAC 5 04-01-2010 12:59 PM
UV Light for HVAC System handy man88 HVAC 9 06-28-2009 08:31 PM
New Home Wiring - Seeking Expert Advice Dirtrnr Electrical 3 02-10-2009 10:33 AM
Quick HVAC / sump pump wiring question MattOverMinder Electrical 4 01-23-2009 07:42 AM
Is 1/2 Pex more restrictive than 1/2 copper? twilightcall Plumbing 19 06-24-2008 07:32 AM




Top of Page | View New Posts

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