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Taco 555-050RP / 571-2 24V Hydronic Boiler Zone Valve Replacement Power Head Actuator (3-Terminal Heat Motor) Engineering Diagram
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SPECFOUNDRY SKU: SF-HVC-101 · BRAND REF: Taco Comfort Solutions

Taco 555-050RP / 571-2 24V Hydronic Boiler Zone Valve Replacement Power Head Actuator (3-Terminal Heat Motor)

Stamped Casting / OEM Numbers: 555-050RP 571-2 570-2 572-2 573-2 555-050

Compatible Units: Taco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone Valves

Critical Dimensions & Spec: 24VAC, 0.9 Amp wax-element thermal actuator; Terminals 1 (Thermostat), 2 (End Switch/Transformer), 3 (Boiler TT); twist-lock mount

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Pre-Order Dimensional Verification Checklist

OEM Cross-Reference & Stamped Casting Number Table

Use this cross-reference table to confirm that the number stamped or printed on your original hardware or circuit board corresponds to SpecFoundry SKU SF-HVC-101:

Stamped / OEM Part Number Manufacturer / System Brand Compatible Models & Years SpecFoundry Replacement SKU
555-050RPTaco Comfort SolutionsTaco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone ValvesDirect Match (SF-HVC-101)
571-2Taco Comfort SolutionsTaco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone ValvesDirect Match (SF-HVC-101)
570-2Taco Comfort SolutionsTaco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone ValvesDirect Match (SF-HVC-101)
572-2Taco Comfort SolutionsTaco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone ValvesDirect Match (SF-HVC-101)
573-2Taco Comfort SolutionsTaco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone ValvesDirect Match (SF-HVC-101)
555-050Taco Comfort SolutionsTaco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone ValvesDirect Match (SF-HVC-101)

Common Failure Symptoms Solved by SF-HVC-101

Technicians and property owners typically replace 555-050RP when experiencing one or more of the following failure modes:

  • One baseboard heating zone stays ice cold while thermostat calls for heat
  • Taco zone valve manual lever pushes down with zero resistance or fails to fire boiler circulator
  • Wax motor failed open causing overheating in one bedroom zone

Step-by-Step Dimensional Verification & Installation Notes

No draining required! Shut off 24V transformer power, label wires on screws 1, 2, and 3, twist existing Taco power head 1/8 turn counterclockwise to lift off brass valve body, and twist-lock new 555-050RP head on.

Related Technical Guide: Taco 571-2 vs. Honeywell V8043E Zone Valve Powerheads, B&G Couplers & Boiler Cross-Reference →

Frequently Asked Technical Questions (555-050RP)

Where is the casting or OEM part number (555-050RP / 571-2 / 570-2) stamped on this part?

On Taco Comfort Solutions assemblies, look for the stamped or die-cast numbers (555-050RP, 571-2, 570-2, 572-2, 573-2, 555-050) on the underside of the metal housing, along the link arm, on the stainless hinge track, or printed on the circuit board/valve label. Note that casting numbers identify the housing casting, so always confirm critical dimensions (24VAC, 0.9 Amp wax-element thermal actuator; Terminals 1 (Thermostat), 2 (End Switch/Transformer), 3 (Boiler TT); twist-lock mount) as well.

Does SpecFoundry SKU SF-HVC-101 directly replace OEM part 555-050RP (555-050RP, 571-2, 570-2, 572-2, 573-2, 555-050)?

Yes. SF-HVC-101 is verified to match the mounting footprint, electrical/mechanical ratings, and dimensional envelope of Taco Comfort Solutions 555-050RP, 571-2, 570-2, 572-2, 573-2, 555-050 used on Taco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone Valves.

What measurements should I verify before ordering SF-HVC-101?

Before ordering, verify: (1) Stamped or OEM code matches one of 555-050RP, 571-2, 570-2, 572-2, 573-2, 555-050; (2) Dimensional spec matches: 24VAC, 0.9 Amp wax-element thermal actuator; Terminals 1 (Thermostat), 2 (End Switch/Transformer), 3 (Boiler TT); twist-lock mount; and (3) Application matches: Taco 555, 556, 557, 570, 571, 572, and 573 Series Hydronic Baseboard Zone Valves.

How fast does SF-HVC-101 ship and what payment methods are accepted?

SF-HVC-101 ships within 1–2 business days from our US warehouse network. Flat-rate US Ground shipping is $8.95, or FREE on orders of $150+. You can check out online immediately via PayPal, Venmo, Credit/Debit Card, or request an Instant Card Payment Link / Net-30 Commercial PO Invoice.

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