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The sturdy three-way switches used in the Airzone solenoid panel connect to the

vacuum and pressure side of the, pump while the common port connects to the field damper tubing.  Normally open or normally closed operation is field-selectable by reversing the

tubing connections.  Each SOL can inflate one or more Flexdampers.  ALL Flexdampers

tied to a solenoid will open and close simultaneously.
Specs: 24V operated at about .33 amps. 4.5"x2.5'" x 3"

Used as replacement or expansion.
Airzone solenoid

 Solenoid -- $64.00


Expansion Pump


NEW!  EP-2 Super Duty Expansion Pump



Introducing our new EP-2 Expansion pump with more powerful vacuum and pressure to insure you get the best performance from your Airzone SPP and SPP-SD Panels.  The pump contains two internal 24VAC relays designed to operate the pump in conjunction with the HVAC blower and furnace.  Two diaphragms give a redundant action for extra long life.  One pump should provide adequate airflow for most applications, except where a large number and/or very large Flexdampers are used.  If more damper speed is needed, order an additional pump.  The pump is designed  for wall mounting next to the solenoid panel and operates whenever the fan, AC or furnace is in operation.  Please note:  When you order our SPP or SPP-SD Panel, one pump is included.


Use Airzone SPP-SD Panels with round and rectangular Flexdampers™.  Airzone™ Solenoid Panels are compatible with any conventional zone control system that supports two-position, 24vac dampers.  This includes, but is not limited to most Zone Control panels made by Honeywell, Durozone, Durodyne, EWC, Aprilaire, Lennox, RCS, Ecojay, Robert Shaw, Zone Perfect and Jackson Controls.

EP-2 Expansion Pump


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Air Zone Test Kit 


This kit includes everything you need to troubleshoot your Flexdamper system, as demonstrated in our troubleshooting video.

Included in kit:

- Dwyer Flow Meter

- Tubing and connectors for attaching flow meter to system to check vacuum and pressure modes on the system

AZ Test Kit --  $39.00
With Free Domestic Shipping



ECL Evaporator Control Limit Switch

RetroZone's popular ECL switch is a great, low cost, low refrigerant temperature switch that prevents AC coil freeze up.  Frozen coils can be caused by improper refrigerant charge, dirty filters, malfunctioning dampers, burned out fans, and many other reasons.  The ECL switch snaps on the suction line at the evaporator coil, and has a simple two wire connection that can wire in series to the "Y" compressor circuit.  At 38° F refrigerant suction line temperature, the contacts open to offline the compressor, and does not reset until 50° F. Flutter-proof snap acting switch will not short cycle compressor, and can also be used to open all dampers on a zoning system. Great protection, great price, and well proven.
Specifications: About l"xl"x2" with bracket., 15 AMP contacts

Evaporator Control Limit Switch -- $13.00




 Fire Rated Connect Tape






Ten yards of special heat activated tape for joining ends of round Flexdampers not needed for rectangular Flexdampers 



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40VA Plug in transformer use on all zone control systems. Fuse protected, screw terminals.  ALSO COMES IN HARDWIRE AND 75VA. Specs: 3.5"x2.75"x2.25, about 1 lb.  24VAC, 40VA, 1.7 AMP


40 Va Plug In Transformer -- $19.00


40 Va Hardwire Transformer -- $19.00

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75 Va HARDWIRE Transformer

Use with 4 or more solenoids. -- 37.00

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