Yes, you can absolutely serve both the 240V heat exchanger and the 120V convenience receptacle from that transformer (SquareD 9070T1000D31). Here's why and how: Dual Secondary Configuration

This transformer has two 120V secondary windings. By connecting them in series, you get 240V. By connecting to only one of the windings, you get 120V.

1000VA Capacity

1000VA (Volt-Amperes) is the transformer's power capacity. You need to make sure the combined VA load of the heat exchanger and the convenience receptacle is less than 1000VA.

SquareD 9070T1000D31

This specific Square D model is designed for this exact purpose. It is a single-phase, dual-secondary transformer, and its specs confirm it can provide both 120V and 240V.

Here's how to wire it


480V Primary

Connect the 480V input to the primary side of the transformer, following the diagram on the transformer's nameplate. Be sure to use the correct terminals and wiring method, including proper overcurrent protection (fuse or circuit breaker) on the 480V side.2.

240V Connection (Heat Exchanger)

Connect one end of the first 120V secondary winding to one end of the second 120V secondary winding. This is a series connection. The two remaining free ends of these secondary windings are your 240V output terminals. Connect these terminals to the heat exchanger. Remember to use appropriate overcurrent protection (fuse or circuit breaker) on the 240V side as well.3.

120V Connection (Convenience Receptacle)

Connect one of the 120V secondary windings to neutral and the other wire of that same winding to hot. These are your 120V output terminals. Connect these to the convenience receptacle. Ground the receptacle properly. Again, use proper overcurrent protection (fuse or circuit breaker) on the 120V side.

Important Considerations and Recommendations



Load Calculation

Crucially important: Calculate the VA demand of both the heat exchanger and the convenience receptacle. For the heat exchanger, look at its nameplate to determine its voltage and current (or VA) rating. For the convenience receptacle, assume a realistic maximum load. For example, if you expect someone might plug in a small appliance that draws 5 amps at 120V, that's 600VA. The sum of the VA demand for both the heat exchanger and receptacle MUST be below 1000VA. If it's close, consider a larger transformer.

Overcurrent Protection

You must use properly sized fuses or circuit breakers on both the 240V and 120V outputs, as well as the 480V input. The correct size for the overcurrent protection depends on the transformer's rated current output and the size of the load connected to the output. Refer to NEC (National Electrical Code) and your local electrical codes for the correct sizing procedures. It is typically based on the VA rating divided by the voltage. Consult a qualified electrician to determine the correct sizing for your specific application.

Wiring Methods

Use appropriate wire gauge, conduit, and connectors that are rated for the voltage and current. Follow all applicable electrical codes.

Grounding

Proper grounding is essential for safety. Make sure the transformer is properly grounded according to electrical codes.

Safety

Work on electrical equipment only if you are qualified and trained to do so. Otherwise, hire a licensed electrician. Always de-energize the circuit before working on it.

Nameplate and Wiring Diagram

The transformer's nameplate will have a wiring diagram. Follow that diagram carefully. It will show the correct connections for the primary and secondary windings.

Balanced Load (Ideally)

While not critical in a small application like this, it's best practice to try to balance the load across the two 120V secondary windings if possible. If the heat exchanger draws significantly more power than the receptacle, this is less of a concern.

In summary: Yes, the SquareD 9070T1000D31 can power both your 240V heat exchanger and 120V convenience receptacle, provided the total VA load is less than 1000VA, and provided you wire it correctly with proper overcurrent protection and grounding according to electrical codes. Always consult a qualified electrician for the final design and installation. Flag for review