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 11-18-2008, 12:25 PM   #1
Newbie
 
Join Date: Nov 2008
Posts: 5
Share |
Default

Honeywell RTH8500 spare contacts?


Hi,

I am wondering if anyone knows if there is a spare set of contacts on the Honeywell RTH8500 thermostat. I have an air to air exchanger that I would like to turn on only when the furnace kicks in.....instead of running constantly.

golfnut65 is offline   Reply With Quote
Old 11-18-2008, 01:06 PM   #2
Member
 
Join Date: Sep 2008
Location: Upstate New York
Posts: 368
Default

Honeywell RTH8500 spare contacts?


Quote:
Originally Posted by golfnut65 View Post
Hi,
I have an air to air exchanger...
Do you mean an HRV or ERV unit?

Quote:
Originally Posted by golfnut65 View Post
Hi,
...that I would like to turn on only when the furnace kicks in.....instead of running constantly.
Do you mean whenever the fan runs, or just heat and cool?

dac122 is offline   Reply With Quote
Old 11-18-2008, 01:31 PM   #3
Newbie
 
Join Date: Nov 2008
Posts: 5
Default

Honeywell RTH8500 spare contacts?


Hi,

I would like it to come on in either mode.....when heating or if the furnace fan comes on. I only run the air exchanger in the winter, so probably only when the heat comes on.....but if the heat kicks in, the furnace fan runs as well.
golfnut65 is offline   Reply With Quote
Old 11-18-2008, 01:42 PM   #4
Member
 
Join Date: Sep 2008
Location: Upstate New York
Posts: 368
Default

Honeywell RTH8500 spare contacts?


Then I think it could be energized or switched from either the tstat or air handler depending on what you have. If you just want to know if its possible to hire someone else then I think so, but if you want to diy we're gonna need a whole lot more info such as: what exactly is the unit, and how is it switched now; what type of air handler do you have and how is it controlled now; and anything else you can think of?
dac122 is offline   Reply With Quote
Old 11-18-2008, 01:48 PM   #5
Newbie
 
Join Date: Nov 2008
Posts: 5
Default

Honeywell RTH8500 spare contacts?


It is a Lennox furnace....and a Lennox HRV unit. The HRV has it's own humidstat. So, the HRV will continue to run to try and satisfy the humidity in the house even though the furnace is not running. I think it would make more sense to have the two interact and only kick in when it calls for heat.....and more energy efficient. After all, the HRV mixes with the return air.
golfnut65 is offline   Reply With Quote
Old 11-18-2008, 03:47 PM   #6
Member
 
Join Date: Nov 2008
Location: palm coast fl
Posts: 588
Default

Honeywell RTH8500 spare contacts?


seems like unit should be wired the other way around so that the exchanger runs the furnace fan as needed not the other way round the
easy answer is wire it to the fan terminal in the airhandler,however dont have enough info to say that will even work.the xcange. would have to derive its low voltage from the furnace to begin with. assumeing its controlled by low voltage
kennzz05 is offline   Reply With Quote
Old 11-18-2008, 03:53 PM   #7
Newbie
 
Join Date: Nov 2008
Posts: 5
Default

Honeywell RTH8500 spare contacts?


Ken,

That does make sense doing it that way. I'll have to check into the voltage to see if they can even be used as common together. I was just hoping that the thermostat would have an empty set of dry contacts to break the xchanger power....like an auxillary set.
golfnut65 is offline   Reply With Quote
Old 11-19-2008, 03:41 AM   #8
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,544
Default

Honeywell RTH8500 spare contacts?


Are you trying to humidify, or dehumidify, withe HRV.
HRV's don't add humidity in the winter. Unless its extremely humid outside.
beenthere is offline   Reply With Quote
Old 11-21-2008, 10:14 AM   #9
Newbie
 
Join Date: Nov 2008
Posts: 5
Default

Honeywell RTH8500 spare contacts?


I finally have it working how I want. Now the furnace fan will run when the HRV is on. I use it to dehumidify the house so condensation does not form on the windows.

golfnut65 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
RTH8500 Wiring O and B Terminals dermanj HVAC 11 05-04-2013 08:00 PM
help with installation of Honeywell RTH8500 thermostat dg xy HVAC 19 07-28-2009 12:25 PM
new honeywell rth6300b to replace very old honeywell thermostat Designman20 HVAC 2 05-06-2009 04:43 AM
help with installation of Honeywell RTH8500 thermostat dg xy Electrical 2 11-13-2008 07:03 PM




Top of Page | View New Posts

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