'/%3E%3C/svg%3E)
Hover image to zoom
 --%3E %3Csvg version='1.1' id='Fill' xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' x='0px' y='0px' viewBox='0 0 100 100' enable-background='new 0 0 100 100' xml:space='preserve'%3E %3Cpath fill='%23F15C02' d='M79.44,0.95H20.56C9.78,0.95,0.95,9.78,0.95,20.56v58.87c0,10.79,8.82,19.61,19.61,19.61h58.87 c10.79,0,19.61-8.83,19.61-19.61V20.56C99.05,9.78,90.22,0.95,79.44,0.95z M65.38,58.24l9.38,29.58L49.69,69.78L24.5,87.82 l9.34-29.6L8.8,39.6l30.73-0.17c0,0,6.98-19.61,10-28.93c0.54,1.36,9.88,29.1,9.88,29.1H91.2L65.38,58.24z'/%3E %3C/svg%3E){kind=small}
Hover image to zoom
' fill='%23F15C02' d='M49 0C21.938 0 0 21.938 0 49s21.938 49 49 49 49-21.938 49-49S76.062 0 49 0m0 82.709a7.54 7.54 0 1 1 0-15.08 7.54 7.54 0 0 1 0 15.08m7.54-28.412a7.541 7.541 0 0 1-15.08 0V22.831a7.54 7.54 0 0 1 15.08 0v31.466z'/%3E%3C/svg%3E)
SR501-4 has been discontinued
Discontinued May 4, 2026
This product was discontinued by the manufacturer.
MANUALS (3)
This item replaces: SR501, SR501-2, SR501-5, SR100
'/%3E%3C/svg%3E){kind=small}
Direct Replacement:
1 Zone Next Generation Switching Relay, Expandable
Product Highlights
–
120 VAC Input
1
5-1/4"
2-3/4" Depth
7.2 Amps
120v
Description
–
Taco SR501 Single zone switching relay is a standard equipment for every installer. It can easily replace any brand made by any manufacturer, and will even fit into the existing metal enclosure without rewiring incoming connections. The SR501 single zone switching relay is UL and CSA listed, uses a standard "ice cube" replaceable relay and is compatible with conventional and programmable thermostats. External indicator lights provide instant diagnostic feedback, making a snap of service calls or new installation start-ups.
Features:
Features:
- External Indicator Lights
- Switchable Priority
- Simplified Wiring
- Fully Enclosed Snap-Out Relays
- Compact Design
- Fuse Protected
- 100% Factory Tested
- Isolated End Switch
- Contractor Friendly PC Board Layout
- Universal Thermostat Compatibility
- UL and CSA Approved
- 24 Volt Power Input or Output Terminal
- Extended 3 Year Warranty
- Made in the USA
Specs
–
| Application: | Zoning |
|---|---|
| Number of Zones: | 1 |
| Width: | 4-1/4" |
| Height: | 5-1/4" |
| Depth (Inches): | 2-3/4" |
| Amperage: | 7.2 |
| Power Method: | 120 VAC Input |
| Voltage: | 120v |
Questions?
Speak with a real person who will go out of the way to help!
Call or text 888-757-4774
Monday – Thursday
8am–7:45pm
Friday
9am–7:45pm
Saturday – Sunday
9am–5:45pm
Compare Similar Products
Brand
Number of Zones
You May Also Need
3 Replacement Parts
Replacement Fuse - 5 Amp (10 Pack)
SKU: SR5A-005RP
TacoReplacement Fuse - 1 Amp (10 Pack)
SKU: SR1A-001RP
TacoReplacement Fuse - 6 Amp (10 Pack)
SKU: SR6A-001RP
Taco
Need help finding a replacement part?
Fill out the part request form and someone will get back to you shortly.
PART REQUEST FORM
Product Reviews
4.78 out of 166 reviews
98% would recommend this product
5 star
85%
4 star
11%
3 star
2%
2 star
1%
1 star
1%
Customer Images
Most Liked Positive Review
Zones!
Bumping my system from three zones to ten, this controller was the perfect choice for the master position. Wiring is basic & easy, Controls the furnace & four Taco 007-f5 circulator pumps, and (in my system anyway) two Taco 503 relays.
VS
Most Liked Negative Review
 --%3E %3Csvg version='1.1' id='With-RB' xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' x='0px' y='0px' viewBox='0 0 100 100' enable-background='new 0 0 100 100' xml:space='preserve'%3E %3Cpath fill='%23FBC8B4' d='M79.44,0.95H20.56C9.78,0.95,0.95,9.78,0.95,20.56v58.87c0,10.79,8.82,19.61,19.61,19.61h58.87 c10.79,0,19.61-8.83,19.61-19.61V20.56C99.05,9.78,90.22,0.95,79.44,0.95z M65.38,58.24l9.38,29.58L49.69,69.78L24.5,87.82 l9.34-29.6L8.8,39.6l30.73-0.17c0,0,6.98-19.61,10-28.93c0.54,1.36,9.88,29.1,9.88,29.1H91.2L65.38,58.24z'/%3E %3C/svg%3E){kind=small}
Fairly good. Could be better.
Needs better construction. The legs that hold the circuit board to chassis are plastic and weak. These were damaged during shipping, causing indicator led lights to be misaligned. Functional but a fail on robust build! Please improve Taco.
Showing 1-10 of 166 reviews
Broke down in the first season
Installed in August, indicator lights failed by December, then began sending heat to zones with no signal, called taco they sent me here for a warranty replacement, and Supply House sent me back to Taco on a run around, purchased name brand to avoid this type of trouble, last time I purchase from either company
Angry in VT
Vermont
1 months ago
Was this review helpful to you?
I would not buy again
installed unit , lest than a week later all lights for power and zones do not work, relays still work. moved control board alittle bit and lights started working again. most likely there is a break in the Netural ( return) in the board.
bri
NY
6 months ago
Verified Buyer
Was this review helpful to you?
This zone controller is what i needed
It was delivered quickly and was packed well
D Emme
New Jersey
6 months ago
Verified Buyer
Was this review helpful to you?
Good product
Bought this to replace 20 yr old unit since mechanical relays are present.
Cip
WI
6 months ago
Verified Buyer
Was this review helpful to you?
Solid product.
Bought this to replace old 20+ year pumps that are still running strong but some make weird noises. I do not want them to break in the middle of the winter
Cip
WI
6 months ago
Verified Buyer
Was this review helpful to you?
Works great
Did exactly what I wanted to run multiple pumps with multiple thermostats
Slim
Wisconsin
9 months ago
Verified Buyer
Was this review helpful to you?
Best product
Reliable. Easy to install. Customer service very helpful.
Joe
New York
9 months ago
Verified Buyer
Was this review helpful to you?
6 Zone Relay for Circulator Pumps
This is the newest generation 6 zone relay for circulator pumps. It offers R/W/C connections so it will work for Smart thermostats. It also offers Bluetooth connectivity from within the home to check which zone is active or allowing you to force a zone on. It was an easy DIY replacement of an older Taco switching relay.
RFW5
Boston, MA
1 years ago
Verified Buyer
Was this review helpful to you?
I would buy this again
Great service and the part came ahead of estimated delivery.
Peter
Bayside, NY
1 years ago
Verified Buyer
Was this review helpful to you?
Great price and fast shipping.
Just what I needed and at a great price. I am definitely going to use this site from now on.
Dan
Pa
1 years ago
Verified Buyer
Was this review helpful to you?
Product Q&A
53 Questions53 Questions
Q: the port for the thermostat are they 24v? or line voltage?
Asked by Newbie 16 years ago
Add your answer
Verified Reply- PexSupply StaffThe port for the thermostat is 24V.
Was this review helpful to you?
Q: i would like to replace my burned out honeywell RA832A relay,can i use your taco SR501 one zone switching relay
Asked by sam 16 years ago
Add your answer
Verified Reply- PexSupply StaffYes, you can use the SR501 to replace a Honeywell RA823A.
Was this review helpful to you?
- mike
yes, that will replace the honeywell ra832a. i also think you will like the indicator lights on the sr501.
Was this review helpful to you?
Q: I purchased a knight (lochinvar)KBN150 - I have three zones that I want to control with pumps. There are locations to hook up the boiler circ. pump, the system circ pump and the dhw circ. pump. Where would I this 3 zone switching relay into the system to control the three zone pumps? Or is this the wrong piece of equipment to do the job?
Asked by mdscorey in need 16 years ago
Add your answer
Verified Reply- PexSupply StaffThe SR503-2 switching relay will connect to the following: (1) The Lochinvar Knight boiler control via the end switch (X1, X2) switching relay (2) The 3 circulator pumps (3) The thermostats.
Was this review helpful to you?