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120v Relay w/ Built In 24V Transformer
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$78.21 each
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Product Highlights
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120v
Description
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Features:
- Direct replacement for any brand name relay
- Built-in 24 V transformer for easy installation
- Compatible with 24 V thermostats with 2-wire connections (R, W) or 3-wire connections (R, W, C)
- Immediate relay activation provides improved temperature control and comfort
- Epoxy-soundproofed relay ensures quiet operation
- Low current consumption means multiple relays can be controlled by a single thermostat
Specs
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| Voltage: | 120v |
|---|
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Product Reviews
4.8 out of 35 reviews
89% would recommend this product
5 star
86%
4 star
9%
3 star
6%
2 star
0%
1 star
0%
Most Liked Positive Review
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Very low current output
A typical furnace power supply is 40 VA. This unit (RC840T-120) is 1.2 VA. The current draw of an RC840 (no-transformer model) is 1 VA. That leaves .2 VA / 24 V= 0.008 A. That's 8 mA left to run the thermostat. This is fine for simple 2-wire thermostats. However, using the C wire on my Honeywell Pro 2000 series programmable thermostat caused dropping out and rebooting during certain sequences of button presses. I thought this might be due to voltage sag due to impedance on the 120 volt supply line. However, replacing the RC840T to a standard 40 VA transformer and RC840 completely resolved the issue.
Obviously, the RC840T will work fine on simple 2-wire thermostats. It may work fine on a Nest since those gradually charge a permanent battery. It certainly should not be used for something like zone valves.
VS
Most Liked Negative Review
1.2 VA output vs. typical 40 VA
Nice build quality. However, the extremely low power output is edged out by a relatively simple Honeywell Pro 2000 series programmable thermostat. Using batteries and un-landing the C wire works, but I am not happy. Leaves no room for expansion to extra relays, obviously. Now I need to buy a separate transformer. I would recommend the version without power (no "T" suffix).
Showing 1-10 of 35 reviews
Worked perfect for my needs.
Just what i needed to install a 24 volt thermostat, instead of a line voltage stat, on hanging tube heater.
AirPlus°
Jonesboro AR
3 months ago
Verified Buyer
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Yes works like it's supposed to
Would like it supposed to didn't know this existed it's great
Phil
Fairhaven ma
2 years ago
Verified Buyer
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Very low current output
A typical furnace power supply is 40 VA. This unit (RC840T-120) is 1.2 VA. The current draw of an RC840 (no-transformer model) is 1 VA. That leaves .2 VA / 24 V= 0.008 A. That's 8 mA left to run the thermostat. This is fine for simple 2-wire thermostats. However, using the C wire on my Honeywell Pro 2000 series programmable thermostat caused dropping out and rebooting during certain sequences of button presses. I thought this might be due to voltage sag due to impedance on the 120 volt supply line. However, replacing the RC840T to a standard 40 VA transformer and RC840 completely resolved the issue.
Obviously, the RC840T will work fine on simple 2-wire thermostats. It may work fine on a Nest since those gradually charge a permanent battery. It certainly should not be used for something like zone valves.
J
Baltimore, MD
4 years ago
Was this review helpful to you?
1.2 VA output vs. typical 40 VA
Nice build quality. However, the extremely low power output is edged out by a relatively simple Honeywell Pro 2000 series programmable thermostat. Using batteries and un-landing the C wire works, but I am not happy. Leaves no room for expansion to extra relays, obviously. Now I need to buy a separate transformer. I would recommend the version without power (no "T" suffix).
J
Baltimore, MD
4 years ago
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Worked as expected!
Used this for circulating pumps in a radiant heat system! Works great, very quiet!
Shep
Pa
5 years ago
Verified Buyer
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They always have the specific product I need.
I use these to control wine cellar cooling equipment.
Mike
Tempe AZ
6 years ago
Verified Buyer
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I would buy this product again.
Item worked great, very simple way to go versus a conventional 120V transformer and 24 volt relay.
JC
Cincinnati, OH
6 years ago
Verified Buyer
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I love this relay.
I use this to control cooling equipment.
Mike
Phoenix AZ
6 years ago
Verified Buyer
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Problem solver
I was able to replace 2 line (120v) thermostats with smart ones using this great product. Thank you.
Mechanic
NY
7 years ago
Verified Buyer
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Fantastic for adapting high voltage heating systems to Nest
I've used a number of these Aube relays to adapt Nest thermostats to high voltage heating systems. The integration is simple - a three wire connection to the Nest - which provides control to the relay and power to the Nest.
Tim
Seattle, WA
7 years ago
Verified Buyer
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Product Q&A
2 Questions2 Questions
Q: If I am buying 2 1500 watt 120V heaters. Can 1 relay work for 1 nest? Or do I need 2 relays and 2 nests?
Asked by Anthony 7 years ago
Add your answer
Verified Reply- Supplyhouse.com TeamYou would need 2 of each for 2 heaters.
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Q: Just curious to make sure this is indeed the 120v version. The model number is correct, but the literature refers to different voltages and the picture says 240. Even the Honeywell site has the wrong picture up, but I just wanted to double check before ordering that this is in-fact designed for 120 volt systems. Thanks!
Asked by Reed 12 years ago
Add your answer
Verified Reply- Supplyhouse Staffyes its 120 the 240VAC is part# RC840T-240.
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