Tempstar Transformer for TCH648GKA100 — 208/230V to 24V 40VA | Ships Today
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Overview
This OEM control transformer (part number 1170676) supplies the 24-volt power that runs the contactor coil, thermostat, and safety controls on your Tempstar TCH648GKA100 condensing unit. It steps a 208/230V primary input down to a regulated 24V, 40VA secondary output. A failed transformer kills the entire low-voltage control system: the contactor won't pull in, the thermostat may go dark, and the outdoor unit stays off despite having line power. Buzzing, overheating, swelling, or a burnt smell signals a failing transformer, frequently triggered by a shorted control wire or a stuck contactor coil overloading the secondary.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1170676 |
| Type | Control Transformer |
| Brand | Tempstar |
| Primary Voltage | 208/230V |
| Secondary Voltage | 24V |
| Rating | 40VA |
| Fitment | OEM |
Compatibility
Direct OEM replacement for the Tempstar TCH648GKA100 condensing unit. The same 208/230V to 24V 40VA transformer is used across many ICP-family condensers and heat pumps (Heil, Comfortmaker, Arcoaire). Always confirm the part number against your existing unit before installing.
Installation Guide
- Safety First — Disconnect power at the outdoor disconnect and breaker, then verify zero voltage with a multimeter at both line and control terminals.
- Access — Remove the service/control panel to expose the transformer and the low-voltage terminal block.
- Document — Photograph all primary and secondary wire connections before disconnecting anything.
- Remove — Disconnect the 208/230V primary leads and the 24V secondary leads, then unbolt the transformer from its bracket.
- Install — Mount the new transformer and reconnect the primary to line voltage and the secondary to the 24V control circuit per your photo.
- Test — Restore power and confirm 24V across the secondary terminals and proper contactor pull-in on a cooling call.
Signs You Need a Replacement
- No 24V at the control terminals while line voltage is present
- Contactor will not energize and the outdoor unit won't start
- Transformer is hot, buzzing, swollen, or smells burnt
- Low-voltage fuse blows repeatedly after replacement
Shipping & Returns
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days