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ADP-0241-05A - Installation Instructions

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Installation Instructions for HMI HOYME Adaptor 0241- 05A

24Vac Controlled Voltage - Switches 24Vac/ 120Vac


Refer also to HOYME Installation Instructions: Combustion Air Control Damper, Series HOM;  Replacement/Ventilation Air Control Damper, Series HAC; and Adaptor ADP- 1101- 05A.




     4” x 5” x 2 1/2” (101 x 127 x 64 mm)


This Relay Adaptor may be used as an automatic switch having a 24Vac Coil and 120Vac points to control a line voltage circuit for up to a 5 amp draw such as a 120Vac exhaust fan. It can also be used 100% for 24Vac switching. (See wire diagrams on next page.)


A typical application where all the points are used for 24Vac switching may occur when dry points are used at the exhaust fan switch. When the exhaust fan switch is turned on, the furnace fan and the fresh air damper, if used, will open simultaneously. The fresh air damper, however, will not open for furnace firing.

If the damper is required to open when the appliance fires:

a) Refer to wiring diagram (next page) showing the Power Close Damper with Relay;

- or -

b) Use a regular fresh air damper with an ADP-0242-05A and follow its Installation Instructions;

- or -

c) If controlled line voltage is available from the exhaust fan, use Adaptor ADP-1102-TWP and follow its installation instructions.


Fitness of this Adaptor/Damper combination to satisfy air supply requirements for fuel fired appliances during operation of the


Inter-connected exhaust fan(s) shall be investigated by the enforcing authorities.


Air intake duct installation shall be in accordance with: In Canada - CAN/CSA B149 & B139; In the USA – ANSI/NFPA 54, 2006, ANSI Z223.1 and/or local codes including local codes relating to ventilation air duct installation.


I.D.: ADP-0241-05A; comes with one Relay,

DPDT-Coil-24Vac. Pts-24Vac & 120Vac - 5 Amps.


- One adaptor is required for each heating appliance.  

- Adaptor line voltage leads, connected to the appliance shall be suitably cabled, fastened and enclosed in suitable raceways.

- Refer to local and applicable codes.

- If an auxiliary transformer is required, use an approved 24Vac transformer of adequate capacity.

- Supply for the transformer primary shall be taken from the line voltage supply of the appliance. Refer to applicable codes.

- Always conduct a thorough check-out after installation is complete.

- Affix appropriate labels and follow instructions and warnings on each label.


1. Install motorized air control damper as per instructions supplied with it. Satisfactory operation of the damper is recommended before interconnecting Adaptor.

2. Turn off electrical power supply to the appliance.

3. Connect Adaptor line voltage leads to fan motor circuit as per wiring diagram and applicable codes.

4. Connect 24Vac Damper terminal wires to appropriate Adaptor, transformer and control switches. (See damper wiring diagram for proper circuit.)

5. Turn on electrical power to 24Vac transformer. If damper is a Power Open type, it will remain closed at this time. If damper is a Power Close type, it will close at this time.

6. Turn on selected switches at least 3 times to verify the intended operation of selected circuits.






Note: This marking is also on the cover of the Adaptor unit as well as on a label to be placed next to the wiring diagram of the appliance.


Schematic Wire Diagram of ADP-0241-05A Activated by an Exhaust Fan Auxiliary Relay Switch To Control a Furnace Re-circulating Fan and a Fresh Air Damper.

Damper remains closed during furnace firing.

(See ‘Notes’ for alternatives)


 Suggestion: Use fresh air damper HAC-0X10-OPO/PC. 

X = Diameter of damper, 

PO= Power Open,

PC= Power Close.



Schematic Wire Diagram of ADP-0241-05A Activated by an Exhaust Fan Auxiliary Relay Switch and/or Thermostat Controlling a Furnace Re-circulating Fan, and a Power Close Fresh Air Damper with Relay. Damper also opens during furnace firing.



 Suggestion: Use Fresh Air Damper with Relay 

HAC – 0X11 – OPC where 

X = Diameter of Damper,

1 = Relay, 

PC = Power Close


Note: For PC damper only, a toggle switch in series with 24Vac electrical supply line to the Damper will cause it to open as required.


* Note: For PC damper without relay and if adding a Combustion Air Damper, re-connect Fresh Air Damper from furnace ‘C’ to Green wire of the Combustion Air Damper. Both dampers will open during firing of the furnace.


* Note: If existing ventilation relay (auxiliary relay switch) cannot be located, relay wires presently connected to ‘R’ and ‘G’ of the furnace are to be re-connected to ‘3’ of ADP and ‘C’ of the furnace.  ADP ‘WHT’ will then go to ‘GF’ of the furnace and ADP ‘RED’ will go to ‘GT’ of the thermostat, (if used).

See wiring diagrams.

HMI HOYME Manufacturing Inc.  1-800-661-7382 www.hoyme.com 


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Last Updated (Friday, 01 April 2016 10:46)