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  • 1 Zone Switching Relay Product Image
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    1 Zone Switching Relay SR501-4 1 Zone Switching Relay
    SKU: SR501-4
    Brand: Taco
    (129)
    $60.00 each
    269
    Mon, May 3
    1,906
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    269 Mon, May 3
    1,637 Wed, May 5 – Thu, May 6
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  • 3 Zone Switching Relay Product Image
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    3 Zone Switching Relay SR503-4 3 Zone Switching Relay
    SKU: SR503-4
    Brand: Taco
    (39)
    $150.00 each
    177
    Mon, May 3
    1,545
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    177 Mon, May 3
    1,368 Wed, May 5 – Thu, May 6
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  • 2 Zone Switching Relay Product Image
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    2 Zone Switching Relay SR502-4 2 Zone Switching Relay
    SKU: SR502-4
    Brand: Taco
    (25)
    $142.00 each
    223
    Mon, May 3
    2,118
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    223 Mon, May 3
    1,895 Wed, May 5 – Thu, May 6
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  • 4 Zone Switching Relay Product Image
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    4 Zone Switching Relay SR504-4 4 Zone Switching Relay
    SKU: SR504-4
    Brand: Taco
    (129)
    $182.00 each
    172
    Mon, May 3
    623
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    172 Mon, May 3
    451 Wed, May 5 – Thu, May 6
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  • 2 Zone 120V Switching Relay w/ DPST Switching Product Image
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    2 Zone 120V Switching Relay w/ DPST Switching RA832A1066 2 Zone 120V Switching Relay w/ DPST Switching
    SKU: RA832A1066
    Brand: Resideo
    (31)
    $81.69 each
    299
    Mon, May 3
    299
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    299 Mon, May 3
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  • 6 Zone Switching Relay Product Image
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    6 Zone Switching Relay SR506-4 6 Zone Switching Relay
    SKU: SR506-4
    Brand: Taco
    (129)
    $240.00 each
    73
    Mon, May 3
    605
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    73 Mon, May 3
    532 Wed, May 5 – Thu, May 6
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  • 4 Zone Switching Relay<br>w/ Priority Product Image
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    4 Zone Switching Relay w/ Priority SR504-EXP-4 4 Zone Switching Relay w/ Priority
    SKU: SR504-EXP-4
    Brand: Taco
    (31)
    $190.00 each
    59
    Mon, May 3
    203
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    59 Mon, May 3
    144 Wed, May 5 – Thu, May 6
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  • 1 Zone 120V Switching Relay w/ Internal Transformer, 1 SPST Product Image
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    1 Zone 120V Switching Relay w/ Internal Transformer, 1 SPST RA89A1074 1 Zone 120V Switching Relay w/ Internal Transformer, 1 SPST
    SKU: RA89A1074
    Brand: Resideo
    (18)
    $62.47 each
    202
    Mon, May 3
    202
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    202 Mon, May 3
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  • 3 Zone Switching Relay<br>w/ Priority Product Image
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    3 Zone Switching Relay w/ Priority SR503-EXP-4 3 Zone Switching Relay w/ Priority
    SKU: SR503-EXP-4
    Brand: Taco
    (31)
    $158.00 each
    65
    Mon, May 3
    453
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    65 Mon, May 3
    388 Wed, May 5 – Thu, May 6
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  • 6 Zone Switching Relay<br>w/ Priority Product Image
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    6 Zone Switching Relay w/ Priority SR506-EXP-4 6 Zone Switching Relay w/ Priority
    SKU: SR506-EXP-4
    Brand: Taco
    (13)
    $248.00 each
    55
    Mon, May 3
    262
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    55 Mon, May 3
    207 Wed, May 5 – Thu, May 6
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  • Switching Relay w/ Internal Transformer DPST Line Voltage Relays Product Image
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    Switching Relay w/ Internal Transformer DPST Line Voltage Relays R845A1030 Switching Relay w/ Internal Transformer DPST Line Voltage Relays
    SKU: R845A1030
    Brand: Resideo
    (9)
    $79.94 each
    142
    Mon, May 3
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  • Replacement Fuse - <br>6 Amp (10 Pack) Product Image
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    Replacement Fuse - 6 Amp (10 Pack) SR6A-001RP Replacement Fuse - 6 Amp (10 Pack)
    SKU: SR6A-001RP
    Brand: Taco
    (5)
    $18.38 each
    29
    Mon, May 3
    58
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    29 Mon, May 3
    29 Wed, May 5 – Thu, May 6
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  • Replacement Fuse - <br>5 Amp (10 Pack) Product Image
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    Replacement Fuse - 5 Amp (10 Pack) SR5A-005RP Replacement Fuse - 5 Amp (10 Pack)
    SKU: SR5A-005RP
    Brand: Taco
    (3)
    $14.72 each
    20
    Mon, May 3
    46
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    26 Wed, May 5 – Thu, May 6
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  • 2 Zone Pump Controller Switching Relay with Priority Protection Product Image
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    2 Zone Pump Controller Switching Relay with Priority Protection SP-82 2 Zone Pump Controller Switching Relay with Priority Protection
    SKU: SP-82
    Brand: Azel Technologies
    (9)
    $103.95 each
    33
    Mon, May 3
    33
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    33 Mon, May 3
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  • Universal Switching Relay w/ Internal Transformer Product Image
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    Universal Switching Relay w/ Internal Transformer R8845U1003 Universal Switching Relay w/ Internal Transformer
    SKU: R8845U1003
    Brand: Resideo
    (19)
    $60.45 each
    185
    Mon, May 3
    185
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    185 Mon, May 3
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  • 6 Zone Expandable Switching Relay Product Image
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    6 Zone Expandable Switching Relay ARM6P 6 Zone Expandable Switching Relay
    SKU: ARM6P
    Brand: Argo
    (34)
    $234.99 each
    110
    Mon, May 3
    110
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    110 Mon, May 3
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  • 3 Zone Pump Controller Switching Relay with Priority Protection Product Image
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    3 Zone Pump Controller Switching Relay with Priority Protection SP-83 3 Zone Pump Controller Switching Relay with Priority Protection
    SKU: SP-83
    Brand: Azel Technologies
    (8)
    $125.95 each
    21
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  • 4 Zone Expandable Switching Relay Product Image
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    4 Zone Expandable Switching Relay ARM4P 4 Zone Expandable Switching Relay
    SKU: ARM4P
    Brand: Argo
    (34)
    $205.99 each
    124
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    124 Mon, May 3
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  • 1 Zone Switching Relay Product Image
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    1 Zone Switching Relay AR822II 1 Zone Switching Relay
    SKU: AR822II
    Brand: Argo
    (6)
    $59.82 each
    200
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  • 1 Zone Pump Controller Switching Relay w/ Surge & Fuse Protection (DPDT) Product Image
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    1 Zone Pump Controller Switching Relay w/ Surge & Fuse Protection (DPDT) SP-81 1 Zone Pump Controller Switching Relay w/ Surge & Fuse Protection (DPDT)
    SKU: SP-81
    Brand: Azel Technologies
    (5)
    $53.75 each
    32
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    32
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    32 Mon, May 3
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  • Isolation Relay<br>(Up to 3 Zones) Product Image
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    Isolation Relay (Up to 3 Zones) IR882 Isolation Relay (Up to 3 Zones)
    SKU: IR882
    Brand: Argo
    (16)
    $69.24 each
    23
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    23
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    23 Mon, May 3
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  • UPZCP-1 Single Zone Pump Control  Product Image
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    UPZCP-1 Single Zone Pump Control 98996400 UPZCP-1 Single Zone Pump Control
    SKU: 98996400
    Brand: Grundfos
    (2)
    $61.99 each
    73
    Mon, May 3
    73
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    73 Mon, May 3
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  • 24v Replacement Relay Product Image
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    24v Replacement Relay SR024-001RP 24v Replacement Relay
    SKU: SR024-001RP
    Brand: Taco
    (7)
    $23.99 each
    4
    Mon, May 3
    43
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    4 Mon, May 3
    39 Wed, May 5 – Thu, May 6
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  • 3 Zone Expandable Switching Relay Product Image
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    3 Zone Expandable Switching Relay ARM3P 3 Zone Expandable Switching Relay
    SKU: ARM3P
    Brand: Argo
    (34)
    $167.99 each
    169
    Mon, May 3
    169
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FAQs, Manuals & Videos

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  • Switching relays are used to control the flow of water in a heating system by monitoring temperatures and adjusting boiler water temperature to match the demand. They are used in coordination with circulator pumps and programmable thermostats to control zoning in a hydronic heating system. This makes them ideal for indirect water heaters and priority zoning applications. They maximize efficiency and reduce fuel usage, which saves money. In addition, they provide intermediate switching of a line voltage device from a low voltage controller. Switching relays are available in one to six zone models, and if additional zones are required expandable models provide the ability to expand up to 20 zones.

    We offer a wide selection of Taco, Honeywell , Argo, and Bell & Gossett switching relays for residential and light commercial applications.

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