10-28-2021 03:12 PM
I purchased a new Nest 3rd Gen learning thermostats and as soon as I connect the two wires (white and red wires) to the respective contacts, the heat for that zone turns on. This happens when connected to any of the 3 zones in my house. I chatted with Nest support the other day and they verified compatibility with my heating system which is a 7 year old Peerless Boiler model WBV-03-WPCL. I had my boiler service company come out and he felt the Nest backing plate was defective. However, he tried two different non-nest thermostats and had the same result, calling for heat when it should t be. He then tried a 3rd thermostat, a Honeywell programmable and it worked. However, I wanted Nest since I am using all Nest products in the rest of the house (cameras, doorbell) and want to control with one app. The tech could not explain why he also had problems with two of his thermostats, but maintained the Nest must be defective. I ordered another Nest and installed the two wires to the backing plate and once again, zone called for heat when it shouldn’t and will not turn off. I tried the same new backing plate in another zone and got the same result. So am pretty sure the Nest is not defective, but there has to be some compatibility issue. Have searched everywhere for clues, but not finding any. Hoping someone here has some experience with this and can help. Thanks in advance.
10-28-2021 04:05 PM
While I wish I could offer a fix , I gotta say if a tech tried two different thermostats (non nest) and had the same results then there is no way it's the nest, but it's an issue with the furnace or wiring itself. Did he check the furnaces board ?
10-28-2021 04:10 PM
I agree 100%, I don’t think this is a Nest problem, but hoping someone here has experienced something similar. The weird thing is in my living room zone, I am running a Honeywell thermostat which works fine. When I disconnect the two wires and connect them to the Nest backing plate, the zone calls for heat immediately and will not shut off. So same behavior as other zone. So I’m a bit lost on how to take this forward.
11-02-2021 05:18 AM
Looks like this is a known issue with certain boiler control panels. I am using the Taco SR506-EXP and it has an issue with "power stealing thermostats" aka smart thermostats. Found this video on YouTube on how to install a simple resistor in the panel to jump the W and C connectors to resolve the problem. Ordered some resistors (couldn't source locally) and hope this will resolve.
01-10-2022 12:23 PM
Hey 68Jcode,
Sorry for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.
Best regards,
Jake
01-10-2022 12:42 PM
I added a resistor to the panel for both of my Nest thermostats per the video link I shared and they are working perfectly fine. I would suggest Google/Nest write a KB article on this topic as I could not find any info for this symptom when I searched originally.