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gotoman for ac, HVAC Technician
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Experience:  51 years of experience install design and repair of all makes and models of AC
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Hi Nate,Trane xl90 two-stage. I attempted to install a

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Hi Nate, Trane xl90 two-stage. I attempted to install a new thermostat yesterday. a filtrete model which I had successfully installed another property. I'm a girl and and a know nothing about HVAC who maybe should not be touching this stuff, but I'm also stubborn and it's the weekend, so I fear weekend rates for HVAC. I don't know what I did or did not do correctly but I've already blown a fuse twice (and replaced with what appears to be the same color/ number voltage etc from radio shack) I got the thermostat working but doesn't seem to respond correctly. I had to make some guesses on the wiring as of course none of the examples given (filtrete install guide) matched mine exactly. I saw some error codes flashing and so decided to put in the old thermostat and call the filtrete support line Monday. I got the old thermostat back on, hooked up exactly as it was originally (had marked all the wires) and it seems to be working fine. But.. the furnace is still flashing a consistent red light along with a green light from time to time. Did I do some damage? or does it all need to be reset or something. 


I should clarify, the error codes I saw when the new  filtrete thermostat was hooked up, were on the furnace, not on the thermostat

gotoman for ac : Russ here.. If you had a blue wire to B connection on old Trane Tstat it should be connected to C terminal on new thermostat. Russ

Hi Russ, I did connect the blue B wire from the old thermostat to the C on the new thermostat. I was confused by the W1 wire on the old thermostat, there was only a W or W2 slot on the new one, and the Yellow wire from the old thermostat I put on Y, although there is also a Y2 on the new thermostat. About the error codes on my trane now, any idea on that?

gotoman for ac : Tell me where wires were connected on old tstat. Russ
gotoman for ac : How many wires connected on thermostat old thermostat. Russ

5 wires


old thermostat was G, B, R, W & Y


new thermostat has these available :: C,B,O,W,W2,Y, Y2,RH,RC,G,A

gotoman for ac : Jumper R to RC Connect W Y G C It should be fine. Russ



jumper R to RC connect?

gotoman for ac : R is for heating RC controls the cooling. Need a jumper between them. Russ

I see they are already pre- 'jumpered' on the thermostat and I believe they are also 'jumpered' on the control board, I'm going down to verify that now

gotoman for ac : Have you checked for blown fuse on the board. Russ

yes and replaced the 5amp fuse - appears w and w2 was jumpered on the control board. the old thermostat is working, I was just asking about the error codes.. is the red light and green light supposed to be flashing on the control board.


On the new thermostat, it kept saying stage 2 and seemed it took a really long time to come on and then the fan blew hard and then not hard and it just seemed as if something was not right, this why I put the old one in.


and it seems to working fine, I was just asking whether I was seeing error codes.

gotoman for ac : Did you setup the filtrete thermostat. What model werre you using. Russ

I tried.. but it seemed like it was acting funny, so I put the old one back in, it's the 3m-50


I put the old trane therm back in

gotoman for ac : Let me lok up that ttstat be right b ack. Russ

but I see a green flashing light on the furnace control board and cannot find info on it normal?

gotoman for ac : OK. On thermostat touch menue then touch HVAC setup sect option 2. Retry system. Russ
gotoman for ac : select option 2

what is option 2? I'm asking because I do have a 2 stage furnace..and want to make sure I'm setting it all up correctly, also, I have to reinstall it now and I'll be back in touch'


in about 10-15 minutes

gotoman for ac : one stage cool two stage heat. you really do not need two stage heat because the furnace board is only wires to W and is program for two stage heat if needed. Russ

before I hook that thermostat up again, are you having me program it for 1 stage cool? can we speak on the phone again, maybe will go faster

gotoman for ac : Number 2 option is 1 stage cool 2 stage heat. Russ

is there 2 stage cool?

gotoman for ac : Yes but the way you have it wired is one stage cool. Russ

seems the other thermostat had it come on a little and then blow harder after a bit

gotoman for ac : The fan does ramp in cool. Thermostat does not have anything to do with fan ramping.

ok, I put the new therm back together..and I'm going to basement to power it up and then come back up and program it.


Meantime, why would it be wired 1 stage cool, if I have two stages available? also, I cannot find out if the green light flashing on my furnace means there is a


problem, is there a problem ..or is the green light flashing nowmal, I cannot seem to find that on the door where all the codes are

gotoman for ac : According to wiring you hve 2 stage heat one stage cool. Russ

ok, all set up! can you tell me about the green flashing light and I'm sure we're done

gotoman for ac : Green light flashing is CFM of fan. Russ
gotoman for ac : Thanks great job on your part. Sorry it was slow process but I had severe thunderstorms and kept getting knocked offline. Kept loosing Hotspot on phone for my computor. Hope everything is up and running. You did great I am impressed. Russ
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Customer: replied 3 years ago.

Russ, I wish I had known that you were having connection issues, as it felt on this end that you were too busy to read my initial question. which basically was 'I hooked up the filtrete thermostat' but then reinstalled the old one due to some flashing lights on the control board of the furnace. I was afraid I had done something wrong and appears I had not.. that is if the red light contantly flashing and the green light also flashing is normal. I'm still not sure what CFM means, but concluded it didn't mean there was an error. There are error codes and some kind of explanations printed on the inside of one of the doors, but they were not so clear on the green light, and I still wasn't sure on the red light either, I had needed someone to explain that. Meantime, I also wasn't sure if I had hooked up the wires correctly either with the variation on the W, W1, and W2, Y and Y2 options and wanted to make sure I was enabling my particular 2 stage scenario. But it's all hooked up and working it seems, so maybe it's all okay. Hey can you tell me why it is so incredibly cool in the basement where the furnace is and not so much upstairs where the people live? thanks, Elynne

Yes I kept loosing your info. Is the return air open to basement ara. Can you send a picture of furnace location in basement. Russ
Customer: replied 3 years ago.

it's wild down there in the basement .. it's a large old house, w. two separate units, one up and one down, two furnaces in the basement, both w/ air conditioning compressors outside


unit upstairs only has one return in 1500 sq feet, almost impossible to cool up there


Downstairs, 2 returns in 2400 square feet, cools pretty well but both a/c's run 24/7

Is your returns open to basement. area. Russ
Customer: replied 3 years ago.

the return pipes do all run to the basement and the furnaces,

You will find any multi level houses are hard to heat or cool evenly. JUst from natural draft of cool air the basement will naturally be colder. Russ
Customer: replied 3 years ago.

ain't that the truth, as the cold air has to travel far then falls and the vents are all in the floor too. Make any sense to insulate the pipes? or replace the furnace fan for the 2nd level furnace to boost the flow? I re-insulated the attic but didn't make much difference at all.

Main problem is air circulation. What is called air stratofications. Different levels of air in house. Not much to do unless you a variable speed fan on furnace that will keep air circulating. Russ
Customer: replied 3 years ago.

maybe I'll put in a good ceiling fan upstairs - where the ceiling is lofted.

That would help a great deal. Anything to circulate air. Russ
Customer: replied 3 years ago.

ok, well that confirms it.. it's just a tall house, and an old house (115 yrs old) ..needs a respirator, thanks for the chat russ.

No problem. Hope I have helped .. Russ
Customer: replied 3 years ago.

you have..thanks.

thank you.

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