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MANUALS (3)
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Product Highlights
Description
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 |
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Product Reviews
Most Liked Positive Review
Zones!
Most Liked Negative Review
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Fairly good. Could be better.
Broke down in the first season
I would not buy again
This zone controller is what i needed
Good product
Solid product.
Works great
Best product
6 Zone Relay for Circulator Pumps
I would buy this again
Great price and fast shipping.
Product Q&A
53 QuestionsQ: How do I connect two Taco sr504 together (indirect system)to control an 8 zone radiant floor heating using 8 system circulating pump,1 heat exchanger circulating pump, 1 heat exchanger and 8 thermostat?
Asked by Tony 15 years ago
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Verified Reply- PexSupply StaffYou can connect two SR504-EXP switching relays together by setting one to "master" and one to "slave," while plugging the expansion wires on the master unit into the expansion ports on the slave unit.
Q: I am installing an 8 zone radiant floor heating, controlled by 8 thermostat.Please explain to me the differences between Taco controllers sr504-exp-1,sr504-2' and zvc404-exp-1. Which one of these shall I use?
Asked by Tony 15 years ago
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Verified Reply- PexSupply StaffSwitching relays control zones that are zoned by circulator pump and zone valve controls are used on systems that zone by zone valve. EXP models are expandable and you can add controls/relays to them. If you are zoning by zone valve, for example, you could use two ZVC404-EXP.
Q: I have a SR504 Sw Relay and am replacing my 2wire thermostats with the Vivint (APX) CT30 wireless unit. This needs a "C" lead in addition to the "W" and "R" to supply 24v to the CT30. Can I add a connection to provide a C-R (24v)source?
Asked by 15 years ago
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Verified Reply- PexSupply StaffWe would recommend pulling the power from a transformer for the thermostats.
Q: I want to install an additional Safety high limit, would I remove the jumper at ZR-ZC and connect a Open on rise Aquastat ? This is for cold start.
Asked by Joe B. 15 years ago
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Verified Reply- PexSupply StaffAccording to the manufacturer, the ZR terminal is 120-volt output. ZC is 120-volt input to power the circulator relays, which helps explain the need for the jumper. You can use the ZR terminal for 120-volt output, provided you leave the jumper in place.
Q: I recently added underfloor radiant to an existing baseboard heat zone and need a way to run both circulators when triggered by a single thermostat. I currently have 3 zones of baseboard each with its own circulator triggered by an sr503. I added radiant (with it's own circulator)to one of these zones. If I buy an SR 501 for the radiant circulator is there a way to wire it to the sr503 so that when the thermostat calls for heat both circulators run (and the boiler fires)? If I connect both circulators in parallel to the output of the sr503 will the load be too much?
Asked by 15 years ago
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Verified Reply- PexSupply StaffYes, you will need to wire the thermostat to the SR501-2 and wire the end switch of the SR503-2 thermostat connection. You want to cycle on when there is a call for heat.
Q: Is my Taco SR503 acting up? I have 2 zone valves on a simple loop and when the sun room stat asks for heat, the proper zone valve opens, but it only sometimes kicks-in the pump boiler. Is the issue the Fully Enclosed Snap-Out Relay in the Taco, or the white rogers programmable stat? i tried switching around the relays to no avail. System has been running fine for 6 years and even the priority jumper for domestic hot water works great. Bonus Question: Can i add T700 to this unit to track and adjust to outdoor ambient air?
Asked by Mark 15 years ago
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Verified Reply- PexSupply StaffWe would recommend that you check the wiring on the unit to make sure one of the leads is not damaged or defective. You cannot add a PC700 to the SR503-2; you would need the SR503-EXP unit for that.
Q: If i have a 2 zone system both zones have a taco valve and there is a single pump supplying the zones do i need a relay switch to power the pump or will the zone valve control also activate the pump when one or both zones call for heat
Asked by 15 years ago
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Verified Reply- PexSupply StaffThe zone valve controller can activate the pump. You will not need a switching relay to control the zone pump.
Q: I want to use this as a dump valve. when my wood burner over heats I want this to open all 4 valves at the same time to cool my system down. the power to this unit will be dead until the burner overheats to 200 degrees and then my control will turn power on to this. Is this the right unit for me to use for a 4 valve system?
Asked by John 15 years ago
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Verified Reply- PexSupply StaffThis relay is designed for use with pumps. You will need a Zone Valve Controller (ZVC).
Q: SR501 Red LED blinks dimmley all the time. Sometimes the zone controlled by this switch exceeds the thermostst setting by as much as 20 degrees.
Asked by Runnerxlch 15 years ago
Add your answer
Verified Reply- PexSupply StaffIt sounds to us like it could be a wiring issue. We recommend that you go back and check your low voltage and line voltage configurations.
Q: I have 5 zones, each with a normally closed 24 VAC zone valve, and a single circulator on my boiler. I want to use the Taco SR501-2 relay to turn on my circulator only when one or more zone valves are open. Can all 5 of my thermostats be simultaneously wired into the single R and W thermostat contacts of the SR501-2, so that if any single zone valve is called to open the circulator will come on.
Asked by 15 years ago
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Verified Reply- PexSupply StaffNo, they cannot. You will end up back feeding to other thermostats that are not calling for heat. We recommend that you look at the ZVC405-3 instead.
The SR501-2 is looking for closure of a dry contact which in your case is any of the five end switches. If the end switches are wired in parallel and tie to the "T T" terminals the control will start the boiler and pump when any of the five zone valves opens. Do not attempt to isolate the low voltage source inside the SR501-2 as the control transformer for your five thermostats and zone valves it does not have the necessary volt-amperage to manage the loads other than its own internal control. You may use an external transformer likely a 60VA with circuit breaker for control of the five thermostats and zone valves. The secret when working with this control is to use a "dry contact" relay or end switch to activate the control. Make certain that there is no external low voltage source connected with your end switches. The Taco control uses its own transformer to run power across the "T-T" terminals. Mixing an external voltage source by accident will likely burn out a transformer.