What is the difference between HAC-50 and HAC-51?

Both products are identical in construction, size range, actuator, and available options. The only difference is how the relay is specified: the relay is optional on the HAC-50 and standard (included on every unit) on the HAC-51. Specify HAC-51 when a relay output is required on every unit in the system. Specify HAC-50 when the relay is needed on some units but not all.

Why is 7 inch not available in the HAC-50/51 series?

The available sizes in this series are 6 inch, 8 inch, 9 inch, 10 inch, 12 inch, and 14 inch. For 7 inch applications, the standard HAC (Hoyme drive, available through 9 inch) covers that size. If you specifically need a 7 inch damper with the quarter-turn actuator, contact your wholesaler — Hoyme may be able to accommodate a custom order.

What is the difference between the HAC-50/51 and the standard HAC — can I use either on a 6 inch duct?

For 6 inch applications you can use either the standard HAC (Hoyme drive, available to 9 inch) or the HAC-50/51 (quarter-turn quarter-inch drive). Both are CSA certified, both provide the same spring return behavior, and both carry the same option set. The HAC-50/51 is the required choice when the duct exceeds 9 inch — the Hoyme drive is not rated above that size.

Are the heat bypass and insulated body options available on all HAC-50/51 sizes?

Yes — both options are available on all sizes in the HAC-50/51 series. Specify -H for hot air duct supply zone control where full shutoff causes heat buildup, and -L for cold climate installations where the damper body will be subject to condensation. Both are factory-installed — neither is a field modification.

What sizes above 14 inch should I use for larger round duct?

For sizes above 14 inch, use the HAC-40 (Belimo TFB24) which is available in 6 inch through 20 inch in even-inch increments, or the HAC Belimo series for modulating and floating point control.

HAC-50/51 Inline Damper – Quarter-Turn Actuator, 24Vac, 6

Product image is representative only. Actual product may differ in appearance depending on size, configuration, and options selected at order.

The standard HAC option set scaled to 6"–14" round duct. Quarter-turn actuator on a ¼" drive shaft — same spring return fail-safe, same PO/PC configuration, same end switch and relay options as the standard HAC, rated for the torque demands of larger blade areas. CSA certified. HAC-50 and HAC-51 are the same product — the only difference is whether the relay is optional (HAC-50) or standard on every unit (HAC-51).

Confirm PO vs. PC before ordering. The action is factory-set and cannot be changed after installation. PO is correct for fresh air intake and make-up air — duct seals when the system is off. PC is used only when fail-open on power loss is required. Note: 7" is not available in this series — use the standard HAC (Hoyme drive, available to 9") for 7" applications.

✓ Quarter-turn ¼" drive shaft actuator — rated for the torque requirements of 6"–14" blade areas under duct static pressure conditions where the standard Hoyme drive is not

✓ Same spring return fail-safe as the standard HAC — blade springs to fail-safe position on power loss regardless of duct pressure; PO or PC to suit the application

✓ Full option set available on all sizes — end switch, relay, heat bypass (-H), insulated body (-L); all factory-installed

✓ ¼" drive shaft — industry standard interface — actuator replacement not limited to a single proprietary part

✓ CSA certified — complete assembly, Canadian and US installations

✓ Sizes above 14"? — see HAC-40 (Belimo TFB24, 6"–20") or the HAC Belimo series for modulating and floating point control

HAC-50

✓Relay optional — add when needed on specific units

✓Use when relay is the exception — most units don't need it

✓Cleaner ordering when relay-free is the default configuration

HAC-51

→Relay standard — included on every unit automatically

→Use when relay is required on all units — simplifies ordering on multi-zone systems

→Specify size, action, end switch — relay is just there

Size	HAC-50 (relay optional)	HAC-51 (relay standard)	Actuator
6"	HAC-0650-xxx	HAC-0651-xxx	Quarter-turn, ¼" drive
8"	HAC-0850-xxx	HAC-0851-xxx	Quarter-turn, ¼" drive
9"	HAC-0950-xxx	HAC-0951-xxx	Quarter-turn, ¼" drive
10"	HAC-1050-xxx	HAC-1051-xxx	Quarter-turn, ¼" drive
12"	HAC-1250-xxx	HAC-1251-xxx	Quarter-turn, ¼" drive
14"	HAC-1450-xxx	HAC-1451-xxx	Quarter-turn, ¼" drive

7" is not available in this series — use the standard HAC (Hoyme drive, available to 9") for 7" applications.

Actuator

Quarter-turn — ¼" drive shaft

Sizes

6", 8", 9", 10", 12", 14"

Voltage

24 Vac

Action

PO or PC

Certification

CSA — complete assembly

7" Available?

No — use standard HAC

Need ADP furnace fan sequencing? For ventilation code compliance — fresh air interlocked with furnace fan — use an ADP relay adaptor with the end switch variant (SPO or SPC). The ADP opens the damper first, confirms position via end switch, then energizes the furnace fan. See the ADP series for the correct model for your application. For sizes above 14" see HAC-40 (Belimo TFB24).

2-year electrical · 10-year mechanical warranty

CSA certified · Made in Canada · ¼" drive shaft — industry-standard actuator interface

HAC-50 / HAC-51 Inline Air Control Damper — CSA Certified, 24 Vac, 6"–14", Quarter-Turn ¼" Drive

Description

HAC-50 / HAC-51 Inline Air Control Damper — CSA Certified, 24 Vac, 6"–14", Quarter-Turn ¼" Drive