Instruction Sheet 102-385 SR501-EXP-4 Switching Relay SUPERSEDES: March 1, 2013 Plant ID# 9300-2872 EFFECTIVE: December 20, 2013 THERMOSTAT Operation: When the thermostat calls for heat, the circulating pump is energized and the isolated end switch (X and X) will start the boiler. Priority Operation: When the priority dip switch is set to ON and the zone is actuated, all other connected zoning panels will stop operation until the zone is satisfied. When the priority dip switch is set to OFF and the zone is actuated, all other connected zoning panels will operate independently. Mode Operation: When the mode dip switch is set to NORMAL, the end switch relay will be energized if any zone is in operation. When the mode dip switch is set to RESET, the end switch relay will only be energized through the operation of a plug-in reset control or closure of Priority Input. Primary Pump Operation: When the dip switch is set to OFF, the primary circulating pump output will not energize when zone calls for heat. When the dip switch is set to ON, the primary circulating pump output will energize when zone calls for heat. Post Purge Operation: When the dip switch is set to ON, the circulation pump output will stay energized for 2 minutes after its thermostat or aquastat is satisfied, but not operate the boiler. Priority Protection Operation: When the dip switch is set to ON and the zone (priority) on master zone panel calls for heat continuously for more than one hour, then power is returned to the space heating zones allowing all the zones to function independently. Once the zone (priority) on master zone panel is satisfied, the control’s auto-reset is activated and the zone is again allowed to have priority for up to one hour. Pump Exercise Operation: When the dip switch is set to ON, the solid state timer cycles all the circulating pumps that are attached to the Expandable Switching Relay at the selected time interval. The time interval can be set for the pumps to run for either 30 seconds every 2 weeks or for 4 minutes every 24 hours. End Switch: The switch closes when the thermostat calls for heat and the mode switch is set to NORMAL. The end switch also closes when the mode switch is set to RESET and a PC Series boiler reset power control is calling for heat. Expansion Connections: Set the expansion switch to MASTER on the switching relay that has the designated priority zone or is utilizing the PC Series plug-in option. Set all other daisy chained controls to SLAVE. Using thermostat wire (18-22 gauge) connect between terminals A, B, C on the master control to the corresponding A, B, C on the SLAVE control(s). Controls may be daisy chained up to 20 zoning panels using any combination of -EXP controls (120 zones if all are 6 zone panels). Thermostat Input (24 vac): R W C Hot side of transformer. Connect to R on thermostat. Switched R signal from thermostat. Connect to W on thermostat. Common side of transformer. Connect to COM on thermostat (optional). 120 VAC Connections (N is Neutral, H is Hot): Power Input Connect 120 Volt AC power. Primary Primary Pump (optional) N/O Zone Circulator Zone N/C Zone Normally closed terminal for the Circulator Zone. Will deactivate on a thermostat call. Connect to pump neutral leads. N Specifications: PRODUCT NUMBER NUMBER OF ZONES INPUT VOLTAGE MAXIMUM COMBINED LOAD SR501-EXP-4 1 120/60/1 VAC 12 amps TYPE 1 ENCLOSURE WIDTH HEIGHT DEPTH 47/8" 65/8" 23/8" All circulator relay connections, including ZC/ZR, are rated 1/3 hp (6 FLA, 36 LRA) at 120 VAC. The end switch connection is rated 24 VAC, 1 amp. The thermostat connection supplies a 24 VAC class 2 output. WARNING: Wiring connections must be made in accordance with all applicable electrical codes. Use copper wire only. 120 VAC wiring must have a minimum temperature rating of 75°C. Failure to follow this instruction can result in personal injury or death and/or property damage. 12-18 gauge wire recommended for 120 VAC connections, 14-22 gauge wire for thermostat connections, and 14-22 gauge wire for 24 VAC source connections. For information on Taco’s Switching Relays (SR) including catalog sheet, instruction sheets, Visio stencils and our highly praised Zone Controls Wiring Guide, scan the QR code to the left or go to our website: http://www.taco-hvac.com. Wiring Diagram: T See NOTE TO: DHW Aquastat if PC700 Boiler Reset is installed. (See Page 2.) TO: "TT" on Boiler Aquastat POWER CONTROLS END SWITCH EXPANSION THERMOSTAT RESET OVERRIDE X X A B C R W C 1 2 MASTER SLAVE 24 VOLTS AC ONLY OFF PRIORITY ON NORMAL RESET PRIMARY PUMP ON OFF POST PURGE ON PRIORITY PROTECT ON PUMP EXERCISE ON OFF OFF OFF 30 SEC/2 WK ACCESSORY PORT LED INDICATORS 4 MIN/24 HOUR POWER FUSE 6 AMP NOTE: Resistor (1KΩ, 1⁄2 W) may be needed between W and C terminals. ZONE 1 FUSE 6 AMP SINGLE ZONE EXPANDABLE SWITCHING RELAY SR 501-EXP-4 N/O N/C H N H PRIMARY INPUT 120 VAC CIRCULATOR OUTPUT 120 VAC CIRCULATOR PRIMARY CIRCULATOR (OPTIONAL) 120 VAC INPUT Dip Switch Settings: SLAVE ZONE PRIORITY ON RESET PRIMARY PUMP FUNCTION ON POST PURGE ON PRIORITY PROTECTION ON PUMP EXERCISE ON 30 SEC/2 WK MASTER OFF NORMAL OFF OFF OFF OFF 4 MIN/24 HOUR Troubleshooting: • Problem: Digital thermostats do not work correctly when connected to a switching relay. • Solution: Some thermostats are a “Power Stealing” type which means they are powered by the switching relay with just 2 wires (R & W). A resistor may be needed in order to have the thermostat work properly. This resistor should be placed between the W & C (common) terminals of the switching relay. If the thermostat manufacturer does not supply a resistor, a 1000 ohm ½ watt resistor has proven to work with most models and is readily available at electronic supply outlets (e.g. 8the batteries are fresh and installed correctly. • Problem: No heat in a zone or room of building. • Solution: LED diagnostic lights will help find a component that is not working properly. The green LED should always be on, indicating that power is connected and the solid-state fuse is good. When there is a call for heat, the red LED will come on indicating power to the zone circulator. This indicates the thermostat is working correctly. If the red LED does not come on, then check the thermostat and thermostat wiring for errors. This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. SR501-EXP and PC700 Boiler Reset Control Connected to an Existing Switching Relay OUTDOOR SENSOR A Note: If Zone Control comes on without a call for heat, reverse Reset Override input (1 & 2) wires on SR501-EXP. AQUASTAT ON DHW HEATER TO: "TT" ON BOILER AQUASTAT PC700 BOIL OUT SEN SEN ZONE CONTROL THERMOSTATS EXISTING ZONE CONTROL MASTER POWER CONTROLS END SWITCH EXPANSION THERMOSTAT RESET OVERRIDE X X A B C R W C 1 2 BOILER SENSOR SLAVE MASTER X X 24 VOLTS AC ONLY R W R W R R W W ISOLATED ZONE 1 ZONE 2 ZONE 3 ZONE 4 END SWITCH THERMOSTATS (24 VAC) PRIORITY OFF PRIORITY ON T ZONE 4 PRIORITY ON OFF LED INDICATORS NORMAL RESET PRIMARY PUMP ON OFF POST PURGE ON PRIORITY PROTECT ON PUMP EXERCISE ON OFF OFF OFF ACCESSORY PORT ZONE 1 FUSE 6 AMP POWER FUSE 6 AMP POWER LED INDICATORS 4 MIN/24 HOUR 30 SEC/2 WK FOUR ZONE SWITCHING RELAY FUSE 6 AMP FUSE 6 AMP FUSE 6 AMP ZONE 2 ZONE 3 ZONE 1 FUSE 6 AMP FUSE 6 AMP ZONE 4 120 VAC 120 VAC CIRCULATORS PRIORITY INPUT ZC H SINGLE ZONE EXPANDABLE SWITCHING RELAY ZR H ZONE1 ZONE2 ZONE3 ZONE4 N H N H N H N H 120 VAC N H SR 504-4 SR 501-EXP-4 N/O N/C H N H PRIMARY INPUT 120 VAC CIRCULATOR OUTPUT 120 VAC JUMPER DHW HEATER CIRCULATOR CIRCULATOR 120 VAC INPUT H BOILER N PRIMARY CIRCULATOR (OPTIONAL) For additional wiring diagrams, see www.taco-hvac.com. Replacement Switching Relay fuses part number: SR6A-001RP Optional power stealing thermostat resistor part number: SRTR-001RP (Manufacture: Littlefuse, Part Number: 229006) (Value: 1000 Ohms, 1/2 watt or higher) LIMITED WARRANTY STATEMENT Taco, Inc. will repair or replace without charge (at the company’s option) any product or part which is proven defective under normal use within three (3) years from the date of start-up or three (3) years and six (6) months from date of shipment (whichever occurs first). In order to obtain service under this warranty, it is the responsibility of the purchaser to promptly notify the local Taco stocking distributor or Taco in writing and promptly deliver the subject product or part, delivery prepaid, to the stocking distributor. For assistance on warranty returns, the purchaser may either contact the local Taco stocking distributor or Taco. If the subject product or part contains no defect as covered in this warranty, the purchaser will be billed for parts and labor charges in effect at time of factory examination and repair. Any Taco product or part not installed or operated in conformity with Taco instructions or which has been subject to misuse, misapplication, the addition of petroleum-based fluids or certain chemical additives to the systems, or other abuse, will not be covered by this warranty. If in doubt as to whether a particular substance is suitable for use with a Taco product or part, or for any application restrictions, consult the applicable Taco instruction sheets or contact Taco at [401-942-8000]. Taco reserves the right to provide replacement products and parts which are substantially similar in design and functionally equivalent to the defective product or part. Taco reserves the right to make changes in details of design, construction, or arrangement of materials of its products without notification. TACO OFFERS THIS WARRANTY IN LIEU OF ALL OTHER EXPRESS WARRANTIES. ANY WARRANTY IMPLIED BY LAW INCLUDING WARRANTIES OF MERCHANTABILITY OR FIT- NESS IS IN EFFECT ONLY FOR THE DURATION OF THE EXPRESS WARRANTY SET FORTH IN THE FIRST PARAGRAPH ABOVE. THE ABOVE WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR STATUTORY, OR ANY OTHER WARRANTY OBLIGATION ON THE PART OF TACO. TACO WILL NOT BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OF ITS PRODUCTS OR ANY INCIDENTAL COSTS OF REMOVING OR REPLACING DEFECTIVE PRODUCTS. This warranty gives the purchaser specific rights, and the purchaser may have other rights which vary from state to state. Some states do not allow limitations on how long an implied warranty lasts or on the exclusion of incidental or consequential damages, so these limitations or exclusions may not apply to you. CONTROLS MADE EASY.® TACO, INC., 1160 Cranston Street, Cranston, RI 02920 Telephone: (401) 942-8000 FAX: (401) 942-2360. TACO (Canada), Ltd., 8450 Lawson Road, Unit #3, Milton, Ontario L9T 0J8. Telephone: 905/564-9422. FAX: 905/564-9436. Visit our web site at: http://www.taco-hvac.com Printed in USA Copyright 2013 TACO, Inc.