Tempstar Transformer for T8MPN075F16B2 — 40VA 115V to 24V | Ships Today

Overview

This genuine OEM 40VA control transformer (part number 1172810) powers the 24V control circuit on the Tempstar T8MPN075F16B2 gas furnace. It steps 115V line voltage down to a regulated 24V supply for the thermostat, gas valve, ignition control board, and relays. The 40VA rating provides the current headroom these loads need during ignition and blower startup. When the transformer fails, the furnace loses all low-voltage control — the thermostat goes unresponsive, the board won't sequence, and a shorted secondary will repeatedly blow the low-voltage fuse.

Specifications

Compatibility

Factory-correct replacement for the Tempstar T8MPN075F16B2 furnace and ICP/Heil/Comfortmaker siblings built on the same control platform. Verify your existing unit is a 115V-to-24V, 40VA transformer before installing.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter.
2. Access — Remove the control/blower compartment panel.
3. Document — Photograph the primary and secondary lead connections before disconnecting.
4. Remove — Disconnect the line and 24V leads, then unbolt the transformer from its bracket.
5. Install — Mount the new transformer and reconnect primary to line voltage and secondary to the 24V control terminals exactly as photographed.
6. Test — Restore power, confirm 24V at the secondary with a meter, and run a full heat cycle.

Signs You Need a Replacement

• Control board and thermostat are dead while line voltage is present
• Repeatedly blown low-voltage control fuse
• No 24V reading across the transformer secondary
• Burnt smell or scorched transformer windings

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.