Replace Lux ELV4 Thermostat with Ecobee

sandman

Is it possible to replace my Lux thermostat with an Ecobee. The Lux is line voltage on an oil heat system and i have a Taco SR-503. I just need to install the Ecobee on Zone 2.

pecmsg

From your pictures ALL the t-stat wiring is Low Voltage. 

Do you have a picture of the t-stat?

sandman

pecmsg said:

From your pictures ALL the t-stat wiring is Low Voltage. 

Do you have a picture of the t-stat?

This is thermostat I currently have controlling both Zone 1 and Zone 2. I'm looking to just replace it on zone 2.

pecmsg

sandman said:

From your pictures ALL the t-stat wiring is Low Voltage. 

Do you have a picture of the t-stat?

This is thermostat I currently have controlling both Zone 1 and Zone 2. I'm looking to just replace it on zone 2.

That is a high voltage t-stat. Is it connected to high or low voltage?

EdTheHeaterMan

A line voltage thermostat can operate a low voltage circuit, the reverse is not true.
I have a feeling that someone purchased a line voltage thermostat to do the job of a low voltage thermostat.

EdTheHeaterMan

In looking over the thermostat instructions, It appears that the clock and other software and hardware in the thermostat are powered by 2 AA batteries. That would make the switching contacts able to turn a 24 volt system on and off. Although it says not to use this on a 24 volt control system in round about language, it does not specifically have a WARNING not to connect to a 24 volt system. That implies that it might work in my opinion. So you will want to be very careful to measure the voltage on the wires that the thermostat is connected to. If it is around 24 volts +,- then the Ecobee should work just fine. If it is 110V AC or 220 VAC then you can not.

HVACNUT

Ok, yes you can use line voltage thermostats to do 24 volt switching, especially when switching is done with an isolated 3 volts DC.
The issue is, it likely is wired using 14/2 romex or B/X. That's only 2 wires, and leaves you without a wire for a Common to 24 volt power the new thermostats. 

I believe, but not positive, its against NEC to have line and low voltage wiring in the same conduit unless the wire is the same gauge, which it is not. The low volt wires are also running through the line volt section of the SR503. The relays ships with a cardboard divider to keep it separate. 

And where are you getting the 24 volts to power these thermostats? Not the zone panel, right?

Since there's no option for a Common at the thermostats without running new wires, are you planning on using one of those plug in things?

sandman

HVACNUT said:

Ok, yes you can use line voltage thermostats to do 24 volt switching, especially when switching is done with an isolated 3 volts DC.
The issue is, it likely is wired using 14/2 romex or B/X. That's only 2 wires, and leaves you without a wire for a Common to 24 volt power the new thermostats. 

I believe, but not positive, its against NEC to have line and low voltage wiring in the same conduit unless the wire is the same gauge, which it is not. The low volt wires are also running through the line volt section of the SR503. The relays ships with a cardboard divider to keep it separate. 

And where are you getting the 24 volts to power these thermostats? Not the zone panel, right?

Since there's no option for a Common at the thermostats without running new wires, are you planning on using one of those plug in things?

As a last resort if cant run new wire to that location i am going to replace the zone 2 with ecobee hooked directky to the SR503 and just use only the remote sensors for ecobee to control temp for zone 2.  I believe i can use the com connection on the SR503 to power the ecobee. 

HVACNUT

sandman said:

HVACNUT said:

Ok, yes you can use line voltage thermostats to do 24 volt switching, especially when switching is done with an isolated 3 volts DC.
The issue is, it likely is wired using 14/2 romex or B/X. That's only 2 wires, and leaves you without a wire for a Common to 24 volt power the new thermostats. 

I believe, but not positive, its against NEC to have line and low voltage wiring in the same conduit unless the wire is the same gauge, which it is not. The low volt wires are also running through the line volt section of the SR503. The relays ships with a cardboard divider to keep it separate. 

And where are you getting the 24 volts to power these thermostats? Not the zone panel, right?

Since there's no option for a Common at the thermostats without running new wires, are you planning on using one of those plug in things?

As a last resort if cant run new wire to that location i am going to replace the zone 2 with ecobee hooked directky to the SR503 and just use only the remote sensors for ecobee to control temp for zone 2.  I believe i can use the com connection on the SR503 to power the ecobee. 

If you're only connecting one Ecobee to the SR503, fine. Any more might overload the transformer. sandman said:

HVACNUT said:

Ok, yes you can use line voltage thermostats to do 24 volt switching, especially when switching is done with an isolated 3 volts DC.
The issue is, it likely is wired using 14/2 romex or B/X. That's only 2 wires, and leaves you without a wire for a Common to 24 volt power the new thermostats. 

I believe, but not positive, its against NEC to have line and low voltage wiring in the same conduit unless the wire is the same gauge, which it is not. The low volt wires are also running through the line volt section of the SR503. The relays ships with a cardboard divider to keep it separate. 

And where are you getting the 24 volts to power these thermostats? Not the zone panel, right?

Since there's no option for a Common at the thermostats without running new wires, are you planning on using one of those plug in things?

As a last resort if cant run new wire to that location i am going to replace the zone 2 with ecobee hooked directky to the SR503 and just use only the remote sensors for ecobee to control temp for zone 2.  I believe i can use the com connection on the SR503 to power the ecobee. 

If using the existing wiring, and if it's only a 2 wire Romex, then no good. You need 3 wires. Power (R), switching for heat (W), and Common. 

Ecobee might offer something you can use if there's no Common. You can also ask Taco and Ecobee about using a resistor.

SteveSan

If our 1000ohm 1/2watt resistor doesn't work, try a P/N: 684MMR100K MFG: Cornell Dubilier / Illinois Capacitor Disc: 0.68 µF Film Capacitor 63V 100V Polyester, Metallized Radial.

There was a customer here with an issue using our Zone Sentry and Ecobee t-stat. We did some testing and the above resistor fixed his issue. Hope this helps.