Amazon Smart Thermostat Help

OGC81116

Hello! First time homebuyer here. Attempting to connect a Amazon Smart Thermostat. I connected the c-wire (blue) to my Taco SR502 (2 zones) and am getting power to the thermostat but radiators are not turning on. The red light is off for Zone 1 (where I dont have heat) and on for Zone 2 (which is operating normally). Do I also need to connect the blue wire in the boiler (if so, where?) or just on the Taco? Thanks very much in advance.

EdTheHeaterMan

You know the Super Bowl is on now!

EdTheHeaterMan

Are you sure the R from the thermostat is connected to R on zone control thermostat terminal? W on thermostat is connected to the W on the zone control thermostat terminal? then B from the thermostat must be connected to Common on the 24 V transformer terminal. The lower COM terminal where it says 24 VAC

It looks correct but... are the wires spliced inside the walls somewhere? Stranger things have happened!

Zman

It looks like it is wired correctly. The next move would be to check that the wires are all engaged in the terminals.

EdTheHeaterMan

Agree with ZMAN check your wire connections.

OGC81116

@Zman @EdTheHeaterMan Thank you, both. I double checked the wire connections and still no dice. This was my old thermostat setup that was working properly in case this provides more context. Haven't changed anything on the Taco except connect the C wire.

Zman

If you jumper R to W at the t-stat does the boiler fire? If you put your voltmeter on R and C, does it read 24-28 VAC?
If both of these are true, you have a T-stat issue.

HomerJSmith

You have 2 zones and 2 thermostats?

If you have a volt meter(they are cheap) measure the voltage between R and W on the thermostat base, it should be 27V ac. Measure the voltage between R and C, it should be 27V ac. If so look for a problem in the Taco or the wiring to the circulator. A blown fuse, etc.

Are the programing settings correct in the thermostat?

No, just the blue wire to the Taco not the boiler.

HVACNUT

Double check the Common connection on the thermostat. 
You can clearly see the tabs recessed on R and W. It doesn't look like it with the Common. Those push connections are a PIA sometimes. 

EdTheHeaterMan

Is it possible that you need to add a resistor to the thermostat circuit? On the SR502 there is a post from @SteveSan about this problem with the nest thermostat. Perhaps this thermostat has a similar issue

Above screen shot came from this post
https://forum.heatinghelp.com/discussion/180066/taco-sr502-zone-controller-with-nest-stat



You may place the transistor here (see above) if the wire will fit in the terminals on the thermostat, but this may be difficult

If the wires don't fit in the thermostat, then you can place the resistor on the Taco Control as shown below.



However, the resistor wire may not be long enough so you will need to solder an extension wire on the resistor. In this picture make a note that each thermostat may need a separate resistor. If there are too many wires on the common terminal at the green connector, place one wire in the connector under the screw, then wire nut all the other common wires together

SteveSan

You are correct Ed. I would jump the R-W on the Taco to confirm our board is working. Then connect the Nest suggested resistor 220ohm up to 5watt between the R-C terminals on the SR control.

HomerJSmith

So, I assume you have 2 thermostats, one for each zone. Are they both WIFI thermostats?
If so just switch the thermostat wires at the Taco box and see what happens.

It's either one of 3 things. The WIFI thermostat is bad or not programed, the wiring between the WIFI to the Taco is bad or the Taco board is bad.

Forget the resistors, they are a work around for a missing C wire and you have one.

Do this with the WIFI thermo connected with the thermo programed properly. Jump the R & W thermostat connections on the Taco board for zone one. Does the red led come on for zone one and the pump turn on? Yes, then look at the wiring or the thermo. No, look for a problem with the Taco, but you say the old thermo works fine, so, I assume the Taco is ok.

Switch the blue wire between the thermo and the com on the Taco with the green wire. Does the thermo work? Yes, then it was the wiring. No, look at the thermo. You have a display on the thermo so I suspect that the R & W wires are good and the old thermo works.

That leaves the thermostat that is at fault. Make sure the wire connections to the thermo base are properly connected. The pins on the back of the thermo aren't bent. That the programing is correct. This is basically a Honeywell thermostat that works with Alexa.

A simple volt meter and 90 sec would have provided all the answers. Call the themostat helpline for the proper setup and questions.


Question:
Can you use this without the internet?
Answer:
You can not set up the thermostat without going through the Alexa app which requires a connection to the internet. No connection to the internet means no setup and an unuseable thermostat.
By Dano on December 31, 2021

Without programing this ain'ta gona work.

https://www.harborfreight.com/automotive/diagnostic-testing-scanning/multimeters-probes-testers/multimeters/7-function-digital-multimeter-63759.html