Pneumatic HVAC Relays

Electric–Pneumatic Relay: Metal

Change branch or main signals from one source or pressure to another with this compact, 3-way diverting solenoid valve. Ideal for occupied– unoccupied, outdoor changeover, summer–winter or many other uses.

The EP201 is a cast metal valve with 1/8'' NPT ports marked N.O., N.C., and common. Includes two barbed fittings for either 1/4'' or 5/32'' pneumatic tube. The Pneuline models are an exact substitute for the devices in this selection chart:

Electric–Pneumatic Relay: Miniature

• High capacity miniature EP relay
• Metal body at a popular price
• Compact size is convenient for panel mounting
• For up to 120psi
• 3-way, 1/8'' FPT connection

Pneumatic–Electric Relay: DPST

The PE201 closes or opens an electrical circuit using a predetermined air pressure signal. Typical applications includes the control of air conditioners, fans, electrical heating

Connection: 1/4'' barb elements, ducts furnaces and more.
Switch: 12A
Signal: 3 to 30 psi adjustable

Pneumatic–Electric Relay: SPDT

The PE301 series switches are SPDT snap switch activated by an adjustable pneumatic signal. Typical uses are to activate fans, heaters, pumps, chillers, alarms and more.

Connection: 1/4'' barb
Switch: 16A
Signal: 3 to 30 psi adjustable

Pneumatic–Electric Relay: Two-stage

The P10FC-4 provides two-stage pressure electric control for self-contained heating-cooling unit ventilators with mechanical refrigeration.

Connection: 1/4'' barb

• Features two enclosed snap-acting SPDT switches with color-coded terminals
• Includes a calibrated indicator scale for the high trip point

Pneumatic–Electric Relay: Duplex

The P10PA provides continuous fan operation and damper control during day cycle and intermittent fan operation during night cycle. It has Two of the switches are mechanically joined and operate together.

• Three enclosed normally closed SPST switches
• Factory calibration of the mechanically joined switches
• Two calibrated indicator scales to display high trip points

3-SPST 6A Switches: 1 opens high 6#, 2 & 3 open high 18# three normally closed SPST switches.
Connection: 1/4'' barb
Signal: 3 to 30 psi adjustable

Pneumatic Relays

Pneumatic relays perform very useful functions in control systems. All brands work in the same pneumatic signals and can be easily interchanged. Don’t be stuck on a single brand. Pneuline Controls perform the same function just as reliably as brands costing more than double. Standardize and stock one model and use it as your universal replacement. This chart will show you the Pneuline model you need.

Low Pressure Selector

Low Pressure Selectors pass the lowest of two separate signals. A common use for these relays is to select the coldest of two zones to control a heating valve.

Hi Pressure Selector

A High Pressure Selector will pass the highest of two different pressure signals. It is often used to select the hottest of two thermostat signals to control a cooling valve.

Diverting Relay (Switching)

A Diverting Relay (or Switching Relay) acts similarly to an electric SPDT relay, but it is switched (energized) by a pneumatic signal. Adjustable set point 3-23#psi, 5psi differential

Reversing Relay

A Reversing Relay reverses the action of the signal coming into the relay. For example, a direct acting signal is converted into a reverse acting signal. As the input signal increases in pressure, the output is lowered.

Ratio Relay

A Ratio Relay is a relay that increases the output at a preset ratio to the change at the input. The adjustable ratio relay is used to slow down the rate of change. The other relay is used for speeding up the rate of pressure change at a fixed ratio.

Booster Relay or (Amplifying Relay)

Booster Relays (or Amplifying Relays) increase the volume or capacity of a pressure signal without increasing the pressure. They are used to refresh a low volume signal or a signal being sent over a long distance.