Thermostat Wiring

[HaroRider]

Hey all, I am trying to wire up a White Rodgers 1F97-1277 thermostat. My main issue is that I can not get the unit to turn on without the back up batteries. The box says that it can be hard wired to turn on.

My old thermostat worked on hard wire and was connected 24VAC (Hot) at the "RC" terminal and 24VAC (Neutral) at the "Y" terminal.

I connected the new thermostat the same way with no luck.

Does anyone have any ideas on what to try next?

 

[garfunkle24]

Did you check this out?
https://www.arpis.com/sites/default/files/equipment_warranty_manuals/1F97-1277%20Installation%20%26%20Troubleshooting%20Manual.pdf

 

[Caddybill]

If heat only try RH and W/E.

 

[HaroRider]

I have those instructions. Its only heat, single transformer.

I tried connecting the neutral to B and the hot to RH with no luck.

 

[Jim greengo]

If heat only try RH and W/E.

Yeah if it's just a simple heat only system you should only need the red to rh/rc and the white to w.

 

[HaroRider]

Yeah if it's just a simple heat only system you should only need the red to rh/rc and the white to w.

My "W" wires are going to the burner is that not correct?
(Switched)

Where does the neutral side of the transformer go?

 

[Jim greengo]

My "W" wires are going to the burner is that not correct?
(Switched)

Where does the neutral side of the transformer go?

Neutral side of transformer is for gas valve and any other low voltage parts inside of furnace in your situation.
Al the stat is doing is making breaking the connection from the red wire back to furnace when it calls for heat.
If theres a green wire going to stat,just hook it to g.
That's to manually turn blower in furnace on and off.

 

[HaroRider]

This is an oil burner, with radiators. No gas valve or fan.

Here is what the instructions are saying to do.

 

[HaroRider]

Here is how the old one was connected.

 

[fitter30]

If you touch red and white wires together the furnace should run. R goes to RH and white wire goes to W. Thermostat can only run on batteries with no common wire. Look at page 2 of the installation manual right column. Take note of the power assistant option and the programing of the stat.

 

[dogdog]

Don't remember the old wiring and thermostats, the new standard ones are:

Neutral side of the transformer is C
Hot side of the transformer is RC and RH.


the switch is the W...

When your system calls for heat it is just a relay that connects RH terminal to W...



here is what I would do... pull out that multi meter... set it to AC Volt and measure the voltage between RH and C... it should have a constant 24V or 24v-ish...

if it checks out good,.... your manual says to Jump RH and RC together for single stage systems... or single transformer systems... or if you are not comfortable then just connect to RC and C and see if your thermostat powers up... it should. and if it does, then you can just jump RC and RH... and keep the C... just make sure you have your R and C correct...



*** just make sure your reading is between RH and C or RC and C and not RH and W or RC W...

 

[HaroRider]

If you touch red and white wires together the furnace should run. R goes to RH and white wire goes to W. Thermostat can only run on batteries with no common wire. Look at page 2 of the installation manual right column. Take note of the power assistant option and the programing of the stat.

With batteries, everything functioned as it should. With no batteries the unit was dead.

Common wire would go to "C" is that correct?

 

[HaroRider]

Don't remember the old wiring and thermostats, the new standard ones are:

Neutral side of the transformer is C
Hot side of the transformer is RC and RH.


the switch is the W...

When your system calls for heat it is just a relay that connects RH terminal to W...



here is what I would do... pull out that multi meter... set it to AC Volt and measure the voltage between RH and C... it should have a constant 24V or 24v-ish...

next I would just get a jumper and jump RH (NOT C) and W... if your system turns on then it's a good sign.. if you are not comfortable with this step... then might have to go check your wiring at the boiler... I wired a thermostat by pass this way... just a toggle switch that connects RH and W when I want to test my boiler and I am too far to walk to the thermostat....anyways..

if those two checks are good,.... your manual says to Jump RH and RC together for single stage systems... or single transformer systems... or if you are not comfortable then just connect to RC and C and see if your thermostat powers up... it should. and if it does, then you can just jump RC and RH... and keep the C... just make sure you have your R and C correct...


the last resort thing is that the transformer you have does not have enough power to power up that thermostat... but normal boilers usually have the 40AH ones and should have enough power... but that will require you to use the multimeter...

if the thermostat draws more power than your transformer can handle... a normal open circuit measure of RH and C that measures 24V would have a voltage dip down if the thermostat is connected with RC/RH and C ...if the transformer does not have enough to handle the new thermostat that is...

*** just make sure your reading is between RH and C or RC and C and not RH and W or RC W...

My RH and RC are jumpered.
Power is going to the RH terminal.

I started to think that it may be an issue with the transformer, but at that point I really wouldn't know what transformer to run.

 

[dogdog]

My RH and RC are jumpered.
Power is going to the RH terminal.

I started to think that it may be an issue with the transformer, but at that point I really wouldn't know what transformer to run.

sorry I had to edit, sometimes I can't even understand what I wrote... but any ways..

for heating only systems and single stage it's usually just 3 wires needed R, C , W...

R and C measures 24V they are literally just the two output end of the low voltage of the transformer (24Vac)... what makes it R and what make it C is literally how it is connected and used (referenced) in the system..

but your thermostat should be able to just power up with just those two wires connected... in your case RC/RH jumper (connected) and C connected, you don't needed any other wires to see if the device powers up..... if you have them correctly...

next is to find which wire is the W...
the W... I am suspecting it is your old B.

and if you are sure that you have the 24Vac properly sourced to RH/RC and C ... you can always take that thermostat and use an external 24VAC to test your thermostat ... it should power up if RH/RC is connect to one end and C is connected to the other end of a 24Vac transformer...

if they don't power up then you should call that 800 number and see if there is a special setting you have to do... on the thermostat to make it use AC power... shouldn't needed to.. but do your due diligent first and measure for 24Vac on your suspected line first of cause.... your heating system have to be powered on though... to take voltage measurements...

All HVAC transformers are 24V , at least most , maybe some special ones in commercial sector that runs higher... and some really old systems runs on 120VAc...

 

[HaroRider]

I originally had the neutral 24VAC on the "Y" terminal like the old one was set up. I moved it to the "C" terminal and I am getting 24VAC between RH and C. This is still with RH and RC jumpered. Unit still doesn't power up. Im starting to think this is the wrong transformer.

My "W" wire is my green and white stranded wire. It goes to the burner and that section of the unit works. Boiler is able to be commanded on through the unit. (Only when its Battery powered)

 

[fitter30]

Common wire goes to C

 

[dogdog]

you can also see if the voltage dips when it is trying to power thermostat would give you a good indication if it is the problem with a weaker transformer, too thin of wires... usually if your unit is not wifi/smart, and worked on the old thermostat... it might not be that...do you still have the older unit and replace it to see if it works ?

your other option to test is to see if you can find another transformer and just to hook it up the low 24vac output to the thermostat for testing.. one leg goes to Rc/RH and the other goes to C... and see if it powers up at the bench... if it still doesn't then call that help line and see... not sure if there is any further testing... or if you are desperate enough bring the thermostat all the way to the transformer and jump the two output of the transformer directly to RC/RH and C... see if it powers up... if it actually does. at least it tells you it's wiring (safety and measure first of cause,...)

 

[HaroRider]

you can also see if the voltage dips when it is trying to power thermostat would give you a good indication if it is the problem with a weaker transformer, too thin of wires... usually if your unit is not wifi/smart, and worked on the old thermostat... it might not be that...do you still have the older unit and replace it to see if it works ?

your other option to test is to see if you can find another transformer and just to hook it up the low 24vac output to the thermostat for testing.. one leg goes to Rc/RH and the other goes to C... and see if it powers up at the bench... if it still doesn't then call that help line and see... not sure if there is any further testing... or if you are desperate enough bring the thermostat all the way to the transformer and jump the two output of the transformer directly to RC/RH and C... see if it powers up... if it actually does. at least it tells you it's wiring (safety and measure first of cause,...)

I would check the voltage dip at the transformer itself correct?

Old one is put back, fully functional. (I think its on itsxway out though) I had no choice its for a 6 family home and I needed to provide heat.

 

[fitter30]

Look at post 10 stat was working correctly with no C wire. With no C it will ownly work with batteries.

 

[HaroRider]

Look at post 10 stat was working correctly with no C wire. With no C it will ownly work with batteries.

I think I understand that part. However with C connected it will not power up without batteries.

 

[dogdog]

I would check the voltage dip at the transformer itself correct?

Old one is put back, fully functional. (I think its on itsxway out though) I had no choice its for a 6 family home and I needed to provide heat.

I know this is repeated...

1) usually if the transformer does not have enough VA to power everything else including the newer thermostat the voltage would dip when you connected the new thermostat to the system... but anyways you should have a constant 24V at RH/RC and C... it is only two terminal needed to power the thermostat afaik..

2) you mention that there is 24V at Rc/RH and C ... so you might have to check with the manufacture or the fine manual and see if there is a switch or setting.. needed Should be automatic.. I know my older honeywell have secret manuals to set up different type, not too sure about this white rogers...

3) if there is a discrepancy between if it was the wiring or the transformer or thermostat... you can always try to power up the thermostat if you have a 24V transformer to spare... it just needed power to the RC/RH and C... or if you don't have a spare transformer, then try to see if you can find the two output leads of the boiler's transformer and power it directly to the transformer ... to see if it powers up.. at least it eliminate if it is the problem with thermostat, transformer or wiring... that is if you are comfortable doing it of cause...

 

[fitter30]

Have you tried to change the power stealing assist switch to on. If that doesn't work call customer service or put the batteries in. With power assist they last along time
HOMEOWNER HELP LINE: 1-800-284-2925

 

[HaroRider]

Not sure what that switch is. Could you please tell me more?

 

[LS6 Tommy]

I think everyone is overlooking the obvious. The new T-stat is most likely defective.

Tommy

 

[dogdog]

not saying yea or nay ... not really there .

all he has to do is bench test it with a separate 24V transformer... mentioned few times...

 

[fitter30]

Power stealing switch is center of the subbase the part screwed to the wall.

 

[HaroRider]

Possible its defective.

Im going to try to use a different transformer to see if I can power her up.

 

[dogdog]

Possible its defective.

Im going to try to use a different transformer to see if I can power her up.

just do that at the bench ... I normally just use a cord to the transformer 120V side , and just take the output lead one to the C and the other to RC/RH will do... since it's AC... at least you eliminate your doubts thermostat or that transformer and or wiring... ... would have post a pic for you if I was able to find that old 5-1-1 thermostat I have... to show that it would work... but just can't find that old thing anywhere... plenty of 24V transformer in front of me... from 40Va to 300+ VA...

It doesn't hurt to call that 800 number either... they can tell you the power requirements if anything...

 

[Aileron]

if you had common to y and hot to rc and rh jumpered it would be a direct short if the cooling mode enabled. Possibly you fried something in the stat if the transformer still powers up.