Rh wire no power to rh wire e24

[Nest4201]

 

 

It’s been working fine for months since I bought the house with it installed. 
Now, it shows error code “rh24”

Only ac is on, no heat.

The screen said “not connect to HVAC” 

for a brief moment, it went back on normal. Then, a few minutes later, went to rh24 error again

[domenic0223]

I’m having the same problem. AC going in and out. When it goes out I’m getting this message. Breakers fine, wire connections appear fine. Will be off then turn back on for just a couple minutes and go out again. I suspect a problem with the best itself since the power is coming back on momentarily 

[zoeuvre]

Hi folks,

Uh-oh! I'm sorry to hear that your thermostats are giving you an E24 code, which means that no power to the RH wire is detected by your thermostat. Let's see what's going on—a few questions:

1. Are you located in North America or Europe?
2. What's the make and model of your HVAC equipment?
3. How many wires are there?
4. How are the wires labeled?
5. Are the power breakers on, and are you receiving power to your home?
6. Is the display seated? Does it properly lock itself into the base?
7. Are all the wires firmly seated into the terminals with no loose or exposed wires?
8. Does the thermostat charge with a USB cable?
9. What are the power readouts of the Battery, VOC, VIN, and lIN under Settings > Technical Info > Power of your thermostat?

I'll look forward to your responses. 

Best,

Zoe 

[MMass]

I can answer these questions. 

1. North America

2. Rheem heat and air - do not know model

3. 5 wires

4. Y1-G-W1-C-RH

5. Yes and yes

6. Yes and yes

7.Firmly seated and no loose wires

8. When seated, it says batter is low and it is turning off to recharge. When I remove it and try to recharge with USB cable (have tried 2 different cables and chargers), it comes back on almost immediately rather than charging (no blinking green light at top of face) and says for me to reattach it to its base. Again, when I do that, it says battery is low. 

9. Can't get that info because of apparently low battery when I attach to base. 

Only other really odd thing is 2 lights attached to one switch in our master bath behind wall where Nest is attached do not come on when switch is turned on. All other lights in bathroom, bedroom and small entry area when Nest is located work. No breakers are tripped. This is likely not a coincidence, but I cannot determine why this one light switch and the Nest have lost power. Help!

[zoeuvre]

Hi MMass, 

Thanks for posting, and I'm sorry to hear that you're experiencing the same with your Nest Learning Thermostat. Follow these steps to troubleshoot: 

1. Go to the breaker box and check if the breakers flipped.
   • If yes, reset the breakers.
   • If not, proceed to the next step.
2. Check your system’s drip pan or drain tubes.
3. Check the condition of the HVAC fuse.
4. Check if you have an energy savings box.
   • Search for an energy savings box near the electric meter (possibly near their air conditioner).
   • Search for a small box with 2 lights on it (one light is red, the other is usually green). This box allows the utility company to cycle the customer’s air conditioner off and on during certain peak times of the day.
5. Check your air filter.
6. Gather the power readouts from the thermostat.
   • Go to Settings > Technical Info > Power.
     • Battery
     • VOC
     • VIN
     • lIN
7. Make sure the thermostat wires are properly stripped and seated in the thermostat base.

Keep us posted. We're happy to help.

Regards,

Zoe 

[MMass]

Thank you for the fast reply. I followed your instructions. No breakers flipped. Drip pan and tubes dry and fine. But, I found the HVAC fuse in the part of my AC/Heating unit located in the attic. It is a purple 3 amp fuse and it appears to be blown. See photos attached. I don't know why this would have blown last night when i briefly ran the AC. It was 50 degrees outside. Could the low outside  temp have caused this? We do not have an energy savings box.

Battery power readings show 3.789V and Voc/Vin/lin: n/a. What now? Replace the fuse and see what if that cures the issue? As of now, the Nest thermostat will not operate either the A/C nor the heat. Thank you. 

Bar

[zoeuvre]

Hi MMass, 

Thanks for getting back to us, and I appreciate you checking for the steps I said. From the information you provided, it seems that you have identified a blown fuse in the HVAC unit located in your attic. Occasionally, fuses burn out due to one or more reasons. If your HVAC fuse burns out, the system might cut off the power to the thermostat and cause an E24 power error. If you have confirmed that the fuse is blown, it is likely causing the issue with your Nest Thermostat not operating the AC or heat, so consider a fuse replacement. You may follow the steps below on how to change your fuse, but if you're not comfortable, I recommend you contact a Nest Pro.

1. Get a new fuse with the same characteristics as the blown one, the purple amp fuse. You can easily buy replacement fuses from your nearest hardware store. 
2. Ensure the HVAC power is off before replacing the fuse. This is usually done by turning off the circuit breaker in the control panel.
3. However, exercise the utmost caution when attempting to remove the blown fuse and replace it. Make sure that the fuse is firmly seated in its carrier.
4. You then change the fuse and start to turn the power back to the AC switch on the circuit breaker.
5. Once power is on, check that the Nest Thermostat can function with AC and heat. Test the system for a while to see if it operates normally.

Let us know how it goes.

Best,

Zoe 

[MMass]

I bought a pack of 3 AMP replacement fuses this AM. Cut power to the heat and air blower in the attic, took off panels, located the circuit board and replaced the blown fuse. Turned power on, put gen 2 Learning Nest thermostat back on its base and it worked immediately. Do not know what caused the fuse to blow but it is fixed and both our central heating and the Nest thermostat have been working normally since I replaced the fuse about 5 hours ago. 

[zoeuvre]

Hi there MMass, 

Awesome! I'm glad that everything has been sorted out. If you have questions or concerns in the future, feel free to start a new thread, and we'll be happy to help.

All the best,

Zoe 

[MR77]

 Yes i am having the same issue, but with heat. I just bought this thermostat. Installed itmaybe a month ago and this is the 5th or 6 time it has happened.

Battery 3.764v

Voc 37.16v

Vin 33.76v

Lin 40 mA

[MMass]

You have a short somewhere in your wiring. Get an HVAC person to locate the short and repair it. Could be anything from a nicked wire to a bad part. Cause of my fuse blowing ended up being a part that quit working properly on the outdoor half of the system. It was causing a short in the low voltage wiring and would not let me run the AC. Hope this helps.

[MMass]

Same issue began during the night last night. Have had this Nest 2nd gen thermostat for 9 years and has worked perfectly. I turned on A/C briefly last evening and it ran for just a few minutes. It was a little warm in house even tho outside temp was around 50. Went to bed and during night tried to access Next from my iphone app and it said it was offline. I went to the Nest and it showed this e24 error. No breakers are tripped. It is 38 degrees this AM and heat would be nice downstairs. Only other odd thing is one set of lights on same light switch in our bathroom do not come on. The bathroom is behind the wall where the Nest is attached to the wall. Again, no breakers are tripped in breaker box in our attic. What the heck is going on here? 

[LordBennington]

We have a boiler and I installed a Nest 2 weeks ago, it was working great and today it told me there was no power detected. Looking into this issue more, I can see that this is a common problem, so I’m saving myself the headache and returning it for a basic thermostat. 

[MMass]

Understandable but I will say this was the first problem I have had with my 2nd gen Nest in 8 yrs. It has been nice to have it to control temp when out of town. 

[zoeuvre]

Hi LordBennington, 

We're sad to see you go. We're always here to help if you ever change your mind. If you come across other information you'd like to pass along or have more questions, feel free to create a new post along with your thermostat's wiring setup.

Cheers,

Zoe 

[Bunkerworld123]

My thermostat is giving me the same power problem. Wires are ok and other thermostats in the house are working properly.  Wires in all thermostats are connected to W1 and RH for heating. What can I do? I tried everything.  Checked breaks, connected wires again. This is so frustrating 

[zoeuvre]

Hi all, 

@MR77 and , yikes! I'm sorry to hear that you are experiencing the same with your Nest Learning Thermostats. Have you followed the steps I provided above? If not yet, kindly follow those and let me know how it goes. 

Kind regards,

Zoe