Technical Library STAGING
Installation Guides
All products & configurations
Colour Wiring Diagrams
Inspector-ready, every ADP model
Competitor Cross-Reference
Honeywell, EWC, AprilAire & more
CSI Guide Specifications
Three-part, editable Word
Troubleshooting & Service
Relay replacement & conversion
Testing & Certification
CSA & NRC documentation
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Try a shorter term, a diagram number such as 8B7, or a part number such as ADP-1101-05A. If the document you need is not here, call 1-800-661-7382. Technical support is free to contractors and installers, and we will identify the correct diagram for your installation.
Watch & Learn
Video Learning Library
Short, practical videos on damper selection, wiring, and the field questions we hear most, from the same team that answers the technical support line. New episodes post every week on our YouTube channel.
HAC — Why New Builds Need a Motorized Damper
HOM — Why New Houses Starve Their Furnaces of Air
ADP — The One Part That Fails Inspections
More videos on the Hoyme Manufacturing YouTube channel, new episodes every Friday.
Section 1
Installation Instructions
Step-by-step installation and wiring instructions for all Hoyme motorized dampers and ADP interface relay adaptors. PDF documents cover residential and commercial applications across all product families.
HAC — Inline Motorized Air Control Dampers
HOM — Combustion Air Damper
MAC — Motorized Make-Up Air / Fresh Air Damper
HAE — Furnace Fan Generated Air Exchanger
ADP — Interface Relay Adaptors (All Models)
Installation instructions for all Hoyme ADP relay adaptor models. ADP adaptors interlock fresh air dampers, combustion air dampers, exhaust fans, and furnaces — available in 24Vac, 110Vac, 110/24Vac, and millivolt configurations.
Section 2
Colour Wiring Diagrams — HVAC Damper & Relay Adaptor Configurations
Over 80 full-colour wiring diagrams covering every Hoyme damper and relay adaptor configuration. Each diagram is CSA-certified and inspector-ready. Covers HOM combustion air damper installations, HAC fresh air damper installations, ADP relay adaptor wiring, TMADP timer adaptor sequences, and multi-furnace configurations. Click any diagram number to download the PDF.
Diagrams 1–2B1 — HOM Combustion Air Damper Wiring Diagrams
Diagrams 3–3A — Combustion Air + Fresh Air Damper Combined Wiring
Diagram 4 — Fresh Air Replacement Air Damper with Relay, Furnace Interlock
Diagrams 5–5C — 120Vac Exhaust Fan with ADP-1101-05A Relay Adaptor
Diagrams 6–6C3 — 120Vac Ventilation Fan Switch Configurations
Diagrams 7–7B — 24Vac Ventilation Switch and Timer Adaptor Configurations
Diagrams 8–8A9 — Single Furnace, 24Vac Ventilation and ADP-0241 Wiring
Diagrams 8B–8D2 — Two Furnaces, Gas Dryer, and Multi-Fan Configurations
Diagrams 9–9C1 — TMADP Timer Adaptor Ventilation Configurations
Diagrams 10–12D1 — End Switch Proving and High-Volume Exhaust Fan Configurations
Section 3
Product Information Sheets & Part Number Guides
General information sheets, product comparison guides, and part number identification guides for all Hoyme dampers and accessories.
Section 4
Competitive Cross-Reference: Competitor Part Number to Hoyme Equivalent
Match a Honeywell Home (Resideo), EWC Controls (Ultra-Zone), Zonefirst, AprilAire, Field Controls, Effikal or Skuttle part number to the equivalent Hoyme damper or control. Download the complete guide, or the single-page sheet for the brand you are replacing. Every sheet covers round zone dampers, fresh air and make-up air dampers, rectangular dampers, and the combustion air, flue and interlock products these lines do not offer.
| Code | Hoyme Action | Behaviour on Power Loss | Typical Use |
|---|---|---|---|
| OPC | Power close, spring open fail-safe | Springs open on loss of power. Matches a normally open zone damper. | Zone dampers, heat and cool distribution. |
| OPO | Power open, spring close fail-safe | Springs closed on loss of power. Matches a normally closed damper. | Fresh air intake, make-up air, combustion air, exhaust. |
| OPP | Power open and power close | Floating point, 3 wire. No spring return, holds last position. | Modulating, BAS and DDC controlled applications. |
| Prefix | Manufacturer | What it means |
|---|---|---|
| ARD | Honeywell Home | Automatic round damper. Power close, spring open. 5 to 10 in., plus 12, 14, 16, 18 and 20 in. |
| EARD | Honeywell Home | Ventilation round damper. Power open, spring close. 5 to 8 in. only. |
| ZD | Honeywell Home | Rectangular zone damper. Power close, spring open. Ordered as ZD (dim 1) x (dim 2) TZ, actuator on the dim 2 side. |
| MARD | Honeywell Home | Modulating round damper. Floating point, 90 second travel. Not an analog 2 to 10VDC device. |
| TZ, /U | Honeywell Home | TrueZONE designation and packaging suffix. ARD8TZ and ARD8TZ/U are the same damper. |
| RSD | EWC Controls | Round spring return damper. Ordered as size then series, for example 6 RSD. |
| ND, SID | EWC Controls | Rectangular damper and slip-in retrofit damper. |
| RDS, RDSC, RDM | Zonefirst | Round damper. S is 2 wire spring return power close. SC is spring close and power open. M is 3 wire power open and power close. |
| GVD | Field Controls | Gas vent damper. The number is the vent diameter. PL denotes a plastic base motor assembly. |
| RVGP | Effikal | Gas vent damper. Crosses to the Field Controls GVD of the same diameter. |
Complete Cross-Reference Guide
Single-Manufacturer Sheets (One Page Each)
Common Cross-Reference Questions
Which Hoyme damper replaces a Honeywell ARD6TZ?
The HAC-0610-OPC, a 6 inch round damper, power close with spring open fail-safe. The ARD series ships power close with spring open, so the OPC action code is the match. ARD8TZ and ARD8TZ/U are the same damper.
Which Hoyme damper replaces a Honeywell EARD6TZ fresh air damper?
The HAC-0610-OPO, a 6 inch power open damper with spring close fail-safe. This is the most common ventilation size. Note that the EARD line stops at 8 inch, while Hoyme carries 9 inch in the standard spring drive.
Which Hoyme damper replaces an EWC 6 RSD?
The HAC-0610-OPC. Where an RSD has been field reversed to power open with spring close, order HAC-0610-OPO instead. Hoyme supplies the correct action from the factory, so no field conversion is required.
Can I substitute a Hoyme HAC-F for a Field Controls GVD or an Effikal RVGP?
Match the vent diameter, but understand that the fail-safe behaviour is different. The GVD and RVGP are power open and power close and hold their last position when power is removed. The HAC-F is spring open, so it does not restrict the flue on loss of power, and it includes a 10 percent bypass. Confirm the appliance listing and the requirements of the authority having jurisdiction before substituting either product for the other.
What replaces a Skuttle 216 make-up air control?
The 216 is a passive barometric flap with no electrical connection, so it cannot be interlocked to an appliance or sequenced with an exhaust fan. For a controlled, positively sealed intake, specify a HAC-0610-OPO with an OOH or MOH hood, or a MAC terminating-end damper. Ventilation requirements calling for a designated exhaust fan, a centrally located switch marked VENTILATION, and a fresh air intake damper interconnected to the furnace circulation fan cannot be met with a passive device.
Which products have no cross-reference at all?
Combustion air dampers (HOM), motorized all-weather hoods (MOH), terminating-end dampers (MAC), motorized flue dampers (HAC-F), damper interlock relay adaptors (ADP) and positive flow switches (PFS). The manufacturers in this guide do not serve those applications, so there is no equivalent to cross to.
Looking for a part number that is not listed here? Call 1-800-661-7382 or send the competitor part number to hoyme@hoyme.com and we will confirm the Hoyme equivalent, the action code and the correct diameter. Cross-reference support is free to contractors, installers and wholesalers.
Cross-references are a guide to product selection based on damper action, voltage, size and application. They are not a statement that products are identical in construction, performance, listing or certification. Confirm the application, the control sequence, the appliance listing where applicable, and the requirements of the authority having jurisdiction before substituting any product. Custom rectangular dampers (HCR and HSI) are built to order and are non-returnable. Honeywell Home and TrueZONE are trademarks of Honeywell International Inc., used under license by Resideo Technologies, Inc. AprilAire is a trademark of Research Products Corporation. Ultra-Zone is a trademark of EWC Controls, LLC. Zonefirst, Effikal, Field Controls and Skuttle are trademarks of their respective owners. Belimo is a trademark of Belimo Holding AG. Hoyme Manufacturing Inc. is not affiliated with, endorsed by or sponsored by any of these companies. All part numbers are the property of their respective owners and are used here only to identify products for cross-reference purposes. Specifications are subject to change without notice.
Section 5
Guide Specifications for Engineers and Specifiers (CSI Three-Part Format)
Three sections in CSI SectionFormat, written so a mechanical consultant can drop the one they need into a project manual without editing around products the project is not using. Each downloads as an editable Word file with Hoyme named as basis of design, substitution language, submittal requirements, execution and field quality control. Written to CAN/CSA B149.1, CSA B139, CSA C22.1, CAN/CSA F326, SMACNA and the National Building Code of Canada.
Specifying a substitution, or reviewing a submittal against one of these sections? Hoyme technical support will review the damper schedule and interlock sequence with you before the product is released to manufacture, at no charge. Custom rectangular dampers are built to order and are non-returnable, so dimensions and action codes should be confirmed in writing.
Section 6
Testing & Certification Documentation
Independent test reports and CSA certification documentation for Hoyme Manufacturing products. Includes NRC Canada energy performance testing for the HAE furnace fan air exchanger.
Section 7
Troubleshooting & Service Guides
Troubleshooting procedures for HOM combustion air dampers and HAC-F flue dampers, relay replacement kit instructions for SF1 and SF2 kits, and field conversion guides for changing power close to power open operation.
Damper Troubleshooting Procedures
Relay Replacement Kit Instructions
Field Conversion Procedures
Damper action is factory set. Do not change the action in the field on combustion air applications. Where a damper does not operate as intended, follow the published troubleshooting procedure before removing the product from service.
Can't find the document you need?
Contact Hoyme Manufacturing technical support or your local wholesaler. We can help you identify the correct wiring diagram, cross-reference a competitor part number, or edit a guide specification section for your project, free of charge.
Over 40 years of engineering HVAC dampers, controls, and fresh-air components trusted by contractors, inspectors, and distributors across North America.
Who We Are
Hoyme Manufacturing designs and builds specialized HVAC dampers, relay adaptors, and fresh-air components for residential and light-commercial forced-air systems.
Since 1984, our focus has been simple: create components that install quickly, control air reliably, and meet evolving energy and ventilation codes. Today, Hoyme products are trusted by contractors, homebuilders, engineers, and distributors across North America.
What We Build
Hoyme specializes in:
- Motorized dampers for controlled combustion air and fresh-air ventilation.
– Non-motorized dampers for backdraft prevention and airflow control.
– ADP interface relay adaptors that simplify control wiring and integration.
– Furnace fan–generated air exchangers that deliver fresh air using existing ductwork.
Every component is engineered for clear labeling, clean wiring, and dependable airflow control in modern HVAC systems.
Who We Serve
Hoyme components are used every day by:
HVAC contractors who need repeatable installs with minimal call-backs.
Homebuilders and developers who want systems that pass inspection smoothly
Mechanical engineers and designers specifying reliable ventilation solutions.
Inspectors looking for clearly labeled, code-compliant components in the field.
HVAC wholesalers and distributors who depend on stable inventory and consistent quality.
Our Origins
Hoyme Manufacturing began with a problem in a single farmhouse. In the 1970s, founder Cliff Hoyme followed code and installed a passive fresh-air supply duct for combustion. The result was what many homeowners still experience today: an uncomfortably cold basement, wasted energy, and unnecessary strain on the heating system.
Cliff’s solution was simple but powerful — use motorized dampers to control when and how outside air enters the system. That idea grew into a full line of CSA-approved combustion-air and ventilation dampers designed to reduce energy waste, improve comfort, and support modern energy codes such as the Model National Energy Code for Houses (MNECH).
Since then, thousands of contractors, homeowners, and even code officials have installed Hoyme dampers to solve the same problem: uncontrolled cold air and inefficient combustion air.
How We Support Your Projects
Hoyme backs every product with practical support and clear documentation.
– Installation and wiring guides that are inspector-ready and easy to follow.
– Technical support for product selection, wiring questions, and code-compliance guidance.
– Reliable lead times and stocking programs for HVAC distributors.
Whether you’re designing a system, installing dampers on site, or supporting contractors as a wholesaler, our team helps keep your projects moving without delays.