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PistolPete76
06-18-2012, 11:43 AM
I have a G9T06010UPB13A high efficiency furnace. I would like to wire it for summer switch (I have an options on my thermostat). Problem is there is only 2 wires right now that go to my thermostat. Any idea how I can wire the furnace to use that setting? I can run new wire with ease between furnace and thermostat
Thanks for any help.

jadnashua
06-18-2012, 01:40 PM
Not sure what you mean by a summer switch?! If you mean you want to force the fan on, if the furnace supports that, you'd need one more wire. While you are doing it, you might as well run a 5-wire cable, then, should you change anything, you'd likely have enough to support it...actually some can use a sixth wire, but most only use 5. Then, you'd be able to add a/c and support multiple stages, if it supports that, as well.

PistolPete76
06-19-2012, 07:58 AM
Thanks for the response. Yes, I meant I want to force the fan on, since my basement is much cooler than my upstairs. This would equalize temp through the house and in turn cool the top floor a bit since i don't have ac.
I did find another (red) wire that was hiding in my wall behind the thermostat. I can easily attach it to my thermostat. Unfortunately the other end is not attached to the furnace. I'm not sure where should I attach it to, to make the fan go. Any help would be appreciated.

jimbo
06-19-2012, 09:34 AM
Somewhere inside the furnace, possibly on the back of one of the covers, you might find the wiring diagram for the furnace. That will help.

PistolPete76
06-19-2012, 10:57 AM
I'll check tonight. I'm sure there is something there just not sure if it will be marked as (connect fan wire here) lol
I'm fairly handy when it comes to anything, but never messed with furnace before and I don’t want to destroy it by connecting it to the wrong place. (i'm clueless about furnaces) Any generic place it should be in? Like would it be on the motor, or maybe some switch or something. I’m sure they are all different but I’d think they would have similar location for wiring.
Thanks in advance

DonL
06-19-2012, 11:36 AM
If it has only two wires then most likely the Blower is controlled using a Temperature operated switch in the heat exchanger.

You could use a relay in parallel with that blower switch, and control it with a air conditioner thermostat.

jadnashua
06-19-2012, 05:35 PM
Assuming your thermostat has a fan/auto switch, and your furnace has a terminal to control it, generically, it is usually the G or green terminal. Hook that wire up to the G terminal on the thermostat and the other end to the G terminal on the furnace, and it should work. Before you do anything, though, verify by looking at the wiring diagram or call someone familiar with that specific furnace. If you have the owner's manual and/or installation guide, it should show this - figuring it out from the wiring diagram inside the cover can be done, but each company uses their own symbols, and it can be hard to read if you've not worked with them before. Basically, you're applying 28vac to the furnace so it can energize a relay (or other electronic control) to turn the fan on.

PistolPete76
06-19-2012, 07:58 PM
1660916610

I can't see "G" terminal in the furnace. Any idea by looking at the pics?

I have a w-r model 50a50-241 control for my furnace. Where would i attach a wire for low speed or high speed? Would it be on cool, heat, park , or park?
Thanks

PistolPete76
06-20-2012, 08:58 PM
Ok I found the G terminal.
I attached green cable to G terminal in the furnace, and the other end to G terminal on the thermostat
Here is the pic. Still nothing though. My thermostat says that it is working on cool, but the fan does not turn on in the furnace. I tried on and auto option.
Any insight?

DonL
06-21-2012, 05:11 AM
What is the make and model of your thermostat ?

jimbo
06-21-2012, 06:33 AM
Does your T-stat have a fan switch...labeled ON-OFF-AUTO ??

DonL
06-21-2012, 09:17 AM
I think that the red wire should be connected to R. Why the black was used instead of red seems incorrect.

The black may be in the wrong place on the thermostat. That would depend where it connects to the thermostat, and the type of thermostat.

The thermostat may need a Return connected to C. (another wire if it requires power)

May be time to get the voltmeter out, and look at the thermostat manual.

Sounds like it may have On/Auto Fan switch. If not No Go.

With nothing connected to Y, Then the thermostat should not have a Cool mode.

Is this unit connected to a Air Conditioner also ?

PistolPete76
06-21-2012, 10:42 AM
Thanks for all replies.

The model of thermostat is noma 303M
here is the pic for the wiring:
I had only 2 wires attached (as in 2 wire diagram) black into RH and white into W
I added green wire to G both in the furnace and in the thermostat.

I have no AC
I tried to run the fan on heat (it works with the heat but not without)
I tried to run on cool (auto and on option) Thermostat kicks in and it shows that it is cooling, but fan in the furnace does not kick in
Would I need another wire for Y to make it work?

Thanks

DonL
06-21-2012, 11:05 AM
Seems that you could run it on heat and put the temp very low. (So heat is not called for)

Would that make the fan run ?

I don't think a connection to Y will help.

Just connect it for the number of wires you are using.

3 should work.

PistolPete76
06-21-2012, 11:21 AM
I tried that with auto setting, and that didn't work. It only moved the fan when i cranked the heat up (higher than room temp) I never tried with ON all the time (at least that i can remember as i was switching it back and forth). I'll give that a try, though it would be nice to have it to kick in in auto mode, but i'll take what i can get.
Will let you know tonight

thanks

DonL
06-21-2012, 11:35 AM
I tried that with auto setting, and that didn't work. It only moved the fan when i cranked the heat up (higher than room temp) I never tried with ON all the time (at least that i can remember as i was switching it back and forth). I'll give that a try, though it would be nice to have it to kick in in auto mode, but i'll take what i can get.
Will let you know tonight

thanks

It needs to be ON, Auto will not let the fan only run, the way it is wired.

If you want the T-Stat to control the blower only when calling for cooling then it will need to be rewired, from the norm.

PistolPete76
06-21-2012, 12:23 PM
What would have to be changed for that to work?

jadnashua
06-21-2012, 01:49 PM
Do you have the jumpers between the RC and RH as shown in the 3-wire heating diagram?

When the fan switch is in auto, the furnace or a/c generally control the fan, an only indirectly from the thermostat. On heating, it turns on when the air by the heat exchanger gets warm (on many, but not all). On a/c, it often turns the fan on immediately when it calls for cooling. So, if you tried to fool the furnace into thinking it has an a/c unit attached, and you wanted the thermostat to control the fan being on/off, instead of the G terminal, move it to the Y terminal on both ends, and make sure that the thermostat is in the cooling mode. But, if it is wired per the 3-wire heating diagram (with the jumper), putting the fan switch to ON should turn the fan on ANY time the furnace is powered up. The G wire is an override from the furnace's normal control of the blower. When in AUTO mode, the lead is not used, the blower control is all within the furnace based on the thermostat calling for heat/cold, and other internal conditions.

PistolPete76
06-21-2012, 04:17 PM
Just tried to run the fan only on heat but no go. The fan will not turn. So far only way i got it to work is on auto with heat (like it's always been, but that's only good for winter) I'll try to move the wire to y terminal later on when i have a minute and see what happens.
BTW yes i do have the jumper

Thanks a bunch for all your help. will let you know how the Y terminal made out

After switching the wire to Y terminal..... i got nothing :-( hmmmmm

jadnashua
06-21-2012, 07:43 PM
Your furnace may not support a manual fan on function...not all do. What does the manual say about it? Most modern one do, though.

PistolPete76
06-21-2012, 07:55 PM
don't have a manual. it's a 10 year old furnace. It was at my place when i bought it 4 years agon.hmmmm.

Thanks for all your help.

jadnashua
06-21-2012, 09:14 PM
Remember, if it is in cool mode, the house has to be hotter than the setting to turn on. It is the opposite for heat.

DonL
06-22-2012, 08:27 AM
What would have to be changed for that to work?

It looks to me that it is going to require the 4 wire hookup.

It will not know that the air is not installed and will run the fan trying to coll, then shut off after it reaches the therm cool setting.

Do you have 4 wires available from the Thermostat to the furnace ? What is red doing ?

You will need 4 wires if you want it to work the way I understand that you want it.

I do believe that unit is able.


Did you switch to the Y terminal on both ends and put it on cool as Jim recommended ?

PistolPete76
07-09-2012, 07:50 AM
It looks to me that it is going to require the 4 wire hookup.

It will not know that the air is not installed and will run the fan trying to coll, then shut off after it reaches the therm cool setting.

Do you have 4 wires available from the Thermostat to the furnace ? What is red doing ?

You will need 4 wires if you want it to work the way I understand that you want it.

I do believe that unit is able.


Did you switch to the Y terminal on both ends and put it on cool as Jim recommended ?

I only have 3 wires right now. if i manually switch the gass off, the fan will turn on when thermostat is adjusted to heat higher than rm temp. Once on though fan will continue to work even after the temp is adjusted manually to lower heat than rm temp. (strange) Have to shut the breaker off to stop it) This work for aout option. If i set it to "on" possition to run constantly the fan will not turn on when the heat is set to lesser temp thatn air temp in the house.
There is no red wire. black is hooked up to RH white to W and green to G

I'm gonna see if i can add another wire to trick it into ac mode without ac. thanks for all your help. Might take me a while to run that wire. It's been busy summer.

Dana
07-09-2012, 11:32 AM
Thanks for the response. Yes, I meant I want to force the fan on, since my basement is much cooler than my upstairs. This would equalize temp through the house and in turn cool the top floor a bit since i don't have ac.
I did find another (red) wire that was hiding in my wall behind the thermostat. I can easily attach it to my thermostat. Unfortunately the other end is not attached to the furnace. I'm not sure where should I attach it to, to make the fan go. Any help would be appreciated.

Running the fan will somewhat equalize the temps if the basement is fully conditioned with ducts, but it's a pretty inefficient way to achieve any cooling, and in the end could prove counterproductive:

A 600-1000W air handler is adding 2000-3400BTU/hr to the sensible cooling load- think of it as running a 600-1000W space heater in the house. It's unlikely that even through an uninsulated basement slab that the heat transfer through the slab would keep up with even the air-handler portion of the cooling load. A cheap 500W window-shaker air conditioner would be able to move ~2x that amount of heat OUT of the house rather than injecting heat into the house, and it would use less power.

If you're looking for the cooling wind chill of breeze on sweaty skin, use a 100W portable fan/ceiling fan, and turn it off when unoccupied. You'll be adding a lot less heat to the house that way.

DonL
07-09-2012, 12:38 PM
If it is a squirrel cage blower then how would it be adding 600-1000W to the cooling load ?

A 1 horse motor in the air flow may.

Seems like the most you would have to loose is the Electrical power used by the blower.

The duct work may add more heat than the gain of moving the cooler air tho.

Dana
07-09-2012, 02:04 PM
I didn't look up the power rating of the air handler on the furnace in question, but typical old school single-speed furnace blowers are in the 600-1000W range. If it's ECM drive it might only be 350W, but the principle is the same:

All power going into the blower motor eventually shows up as heat inside the building, if the air handler and ducts are all inside of conditioned space. Only a small fraction of that is the direct heating of the motor windings- the bulk of it is in the air resistance at the impellers and ducts, register etc. It's a widely disbursed space heater, but a space heater nonetheless. Energy is neither created or destroyed- 100% of the energy going into the motor ends up somewhere eventually as heat, and all of those "somewheres" are inside the thermal boundary of the house.

DonL
07-10-2012, 07:55 AM
I only have 3 wires right now. if i manually switch the gass off, the fan will turn on when thermostat is adjusted to heat higher than rm temp. Once on though fan will continue to work even after the temp is adjusted manually to lower heat than rm temp. (strange) Have to shut the breaker off to stop it) This work for aout option. If i set it to "on" possition to run constantly the fan will not turn on when the heat is set to lesser temp thatn air temp in the house.
There is no red wire. black is hooked up to RH white to W and green to G

I'm gonna see if i can add another wire to trick it into ac mode without ac. thanks for all your help. Might take me a while to run that wire. It's been busy summer.


I thought you said you had a red wire that you found behind the thermostat in your earlier post.

If you only have 3 wires , and it is working the way you say now, Then you should be able to move 1 wire at the thermostat.

The wire now connected to "W" should be moved to "Y" on the thermostat, and then it should work to cut the fan on and off in cool mode. (Need to leave the gas turned off).

Then when it gets cold and you need heat you can move the wire back, and turn the gas back on.

The long way around but should work. Running 4 wires may cure the swapping of wires, and the need to turn off the Gas.


Dana is correct that it will add some heat also, But you have to decide if it is worth it. If you have better comfort level, It must be doing some good.

PistolPete76
07-10-2012, 08:08 AM
Yes i have a red wire behind, but it was not used. I had to extend too for it to reach the furnace. Now it's (green) just to make it more color complicated lol.

I will try the wire switch. It's not that much work.

with the heat i see what you guys are saying. When I had it running the other day it actually got warmer than cooler. So at the end i may not even use it, but it was cool to learn something new.

Once again thanks a bunch for all your help

DonL
07-10-2012, 09:25 AM
Yes i have a red wire behind, but it was not used. I had to extend too for it to reach the furnace. Now it's (green) just to make it more color complicated lol.

I will try the wire switch. It's not that much work.

with the heat i see what you guys are saying. When I had it running the other day it actually got warmer than cooler. So at the end i may not even use it, but it was cool to learn something new.

Once again thanks a bunch for all your help

I know here where I live it will heat the house because all of our venting is in the attic.

I will use it to heat in the winter and when the sun has the attic temp cooking.

Not much use for cooling tho, if the sun is getting the attic hot.

If you swap the wires, then when it starts running all the time, that means you are starting to heat instead of cool, and you should turn it off.

The wire swap should help some.

Let us know if you have any luck.