Choosing the right furnace replacement relay matters: a wrong relay can mean unreliable heating, nuisance trips, or premature failure. This guide examines dependable relay and contactor options for furnaces, blowers, and hydronic zone control — based on hands-on testing, vendor specs, expert opinion, and consumer feedback.
Considerations
How we tested and selected products
- Real-world usage: We focused on parts commonly used in furnaces, blowers, and hydronic zone controllers (24VAC control relays, fan relays, switching relays). We prioritized compatibility, electrical ratings, and physical fit for common OEM replacements.
- Expert input: HVAC technicians and installers guided which features matter most (diagnostic lights, sealed relays, fuse protection, and wiring simplicity).
- Consumer feedback & durability: We reviewed user reports for longevity, failure modes, and installation issues. Units with visible diagnostics and built-in protections scored higher.
- Bench checks: Where possible, we verified coil voltage, contact ratings, and terminal layout against manufacturer specs to ensure proper replacement behavior.
Key factors that influenced rankings
- Compatibility & fit: Direct drop-in replacements or clearly documented wiring are easier and safer to install.
- Protection & diagnostics: Fuse-protected outputs, sealed relays, and LED indicators reduce service calls.
- Build quality vs. price: We balanced OEM reliability against competent aftermarket options that offer better value.
- Application suitability: Some relays are aimed at blowers/furnaces (fan relays), others at multi-zone hydronic controls — pick based on your system.
Dreyoo 24V Fan Relay
Compact 24VAC SPST fan relay designed for furnace blowers and humidifier/blower sequencers. UL certified, easy to wire with printed diagram, and compatible with many Goodman and HVAC blower applications — a strong, inexpensive choice for straightforward fan or blower replacements.
Why we like it
The Dreyoo 24V fan relay is a practical, no-frills replacement for blower/fan circuits. It uses a 24VAC coil (type 90-980) and supports typical blower FLA ratings (12FLA listed), making it suitable for many furnace blower and humidifier controls. The unit is UL certified, compact, and includes a printed wiring diagram and six hookup terminals for an easy install.
Standout features & analysis
- Compatibility: Designed to work with Goodman and similar blower controls; a good drop-in for many HVAC systems.
- Build & safety: UL certification and straightforward wiring lower installation risk.
- Limitations: Not a multi-zone switching relay — intended for single contact fan/blower applications only. If you need zone switching or multiple outputs, look elsewhere.
Bottom line: For a low-cost, reliable replacement for a furnace blower relay or humidifier control, this is our budget pick.
Taco SR-504-4 Relay
OEM Taco SR-504-4 4-zone switching relay with priority output, external indicator lights, sealed snap-out relays, and simplified wiring. A proven premium solution for multi-zone hydronic heating systems where reliability and serviceability matter.
Why we like it
The Taco SR-504-4 is an OEM multi-zone switching relay built for hydronic systems and multi-zone control panels. It supports four zones with priority switching, external indicator lights for quick diagnostics, sealed snap-out relays, and simplified wiring to speed up installation and service.
Standout features & analysis
- OEM reliability: Taco is a recognized HVAC parts brand; the SR-504-4 is designed for long service life in demanding environments.
- Diagnostics & serviceability: External indicator lights and enclosed snap-out relays make troubleshooting and replacement straightforward for technicians.
- Electrical: Listed amperage and robust construction suit common zone valve/actuator loads.
- Cost: This is the most expensive option here, but the premium price buys OEM fit, brand trust, and proven field reliability.
Bottom line: If you run a multi-zone hydronic system and want the original, proven OEM part, the Taco SR-504-4 is our premium choice.
YILISAWIN SR501-4 Relay
Direct-compatible single-zone replacement for Taco SR501 models. Bright LED indicators, sealed relay construction, universal 24V thermostat compatibility, and full-load testing make this a reliable, affordable alternative to OEM single-zone relays.
Why we like it
The YILISAWIN SR501-4 is engineered as a direct, drop-in replacement for Taco SR501 family relays and targets single-zone control needs. It emphasizes easy installation, bright status LEDs for diagnostics, and durable construction with heat-resistant materials and enclosed relays.
Standout features & analysis
- Direct fit: No wiring change needed when replacing Taco SR501/501-4 units — a real time-saver.
- Diagnostics: LED indicators for power and zone activation reduce troubleshooting time and service calls.
- Durability & testing: Manufacturer reports full-load testing and one-year support; materials are heat-resistant for furnace environs.
- Value: Priced far below OEM parts while delivering near-OEM functionality.
Bottom line: For homeowners or techs who need a reliable single-zone replacement without the OEM price tag, this offers the best value.
DDORUU SR504-4 Relay
4-zone switching relay compatible with SR-504-4 systems. Front diagnostic lights, fuse-protected outputs, sealed relays, and simplified wiring make it a compelling alternative to OEM units for professional installers and savvy DIYers.
Why we like it
The DDORUU SR504-4 is a well-rounded 4-zone switching relay that mirrors the functionality of higher-priced OEM units but at a lower cost. It features front diagnostic lights, external indicators, switchable priority, fuse-protected outputs, simplified wiring, and sealed relays — a feature set installers appreciate.
Standout features & analysis
- Diagnostics & protection: Front diagnostic LEDs plus fuse-protected outputs reduce troubleshooting time and help prevent downstream failures.
- Design: Sealed relays and simplified wiring improve longevity and reduce installation errors.
- Warranty & testing: 100% factory tested and backed by a one-year warranty adds confidence for buyers.
- Considerations: While not the OEM brand, its mix of safety features and diagnostics led us to pick it as our editors' favorite alternative to costly OEMs.
Bottom line: For multi-zone applications where you want strong features and field-focused protections without paying OEM premiums, this relay is our Editors' Choice.
Comparison and Summary
Quick comparison (at a glance):
- Taco SR-504-4 (Premium Choice): 4-zone switching relay, OEM build quality, external indicator lights, sealed snap-out relays — $266.93.
- DDORUU SR504-4 (Editors' Choice): 4-zone switching relay with diagnostic LEDs, fuse-protected outputs, simplified wiring, 1-year warranty — $188.88.
- YILISAWIN SR501-4 (Best Value): Single-zone drop-in replacement for Taco SR501 series, LED diagnostics, tested — $66.99.
- Dreyoo 24V Fan Relay (Best Budget): 24VAC fan/blower relay, UL certified, compact and inexpensive for blower or humidifier control — $13.99.
Which is best overall?
- For multi-zone hydronic systems where OEM reliability and long-term serviceability matter: Taco SR-504-4 is the top pick.
- For most buyers seeking the best balance of features and price (diagnostics, protection, and solid build without OEM pricing): DDORUU SR504-4 is the strongest choice.
- For single-zone or point replacements on a budget with reliable diagnostics: YILISAWIN SR501-4.
- For simple blower/fan relay replacements where cost is the highest priority: Dreyoo 24V Fan Relay.
Notes on selection
- Confirm coil voltage (most furnace control relays use 24VAC) and contact ratings before replacement.
- For multi-zone systems, prefer relays with diagnostic lights and sealed relays to reduce service time and increase reliability.
- Contactors labeled for condenser/compressor applications are different from fan relays and zone switching relays — match function, not just form.
Final Recommendation & Guidance
Bottom line: If you want the absolute OEM solution and are replacing a multi-zone Taco unit, the Taco SR-504-4 is the safest premium option. For most homeowners and installers who want a modern feature set (LED diagnostics, fused outputs, sealed relays) without paying OEM prices, the DDORUU SR504-4 offers the best combination of reliability and value and is our Editors' Choice.
Which product for your situation:
- You have a multi-zone hydronic heating system and prefer OEM parts: choose Taco SR-504-4.
- You want strong features and durability at a lower cost: choose DDORUU SR504-4.
- You need a single-zone, drop-in replacement for an SR501-series relay: choose YILISAWIN SR501-4.
- You need a cheap, reliable fan/blower relay for a furnace blower or humidifier sequencer: choose Dreyoo 24V Fan Relay.
All recommendations are based on a combination of hands-on checks, spec verification, expert input, and end-user reports. Before replacing any relay, always verify compatibility with your furnace model and, when in doubt, consult a licensed HVAC technician to ensure safe and correct installation.