What are the specs for this Transformer?

The correct replacement for Tempstar model T8MPN100F20A1 Furnace — 115V to 24V | Ships Today is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Tempstar equipment which lists the model number T8MPN100F20A1 Furnace — 115V to 24V | Ships Today.

Is this transformer compatible with Bryant or Payne systems too?

Many Tempstar parts are cross-compatible with Bryant and Payne systems since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across multiple brand labels with different model numbers. To verify cross-compatibility, check your Bryant or Payne equipment service manual for cross-compatible part numbers, or contact info@nationalhvacparts.com with your model number for confirmation.

Tempstar

Tempstar 40VA Transformer for T8MPN100F20A1 Furnace — 115V to 24V | Ships Today

Name: Tempstar 40VA Transformer for T8MPN100F20A1 Furnace — 115V to 24V | Ships Today
Brand: Tempstar
SKU: 1012722-GEN
Price: 24.95 USD
Availability: InStock

SKU: 1012722-GEN Brand: Tempstar

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Overview

This OEM control transformer (part number 1012722, "TRANS 115>24 40VA X") supplies the 24-volt control power for the Tempstar T8MPN100F20A1 gas furnace. It steps line voltage of 115V down to a 24V secondary and is rated at 40VA, enough to drive the control board, thermostat, gas valve, and ignition circuit. When the transformer fails, the entire low-voltage control system goes dead: no thermostat display, no call for heat, and the furnace will not respond. Transformers commonly fail from a shorted secondary (often caused by a pinched or grounded thermostat wire) or from an overloaded control circuit. Replacing it restores 24V power to the furnace controls.

Specifications

Spec	Value
Part Number	1012722
Type	Control Transformer
Brand	Tempstar
Primary Voltage	115V
Secondary Voltage	24V
Rating	40VA
Fits Model	T8MPN100F20A1

Compatibility

Designed for the Tempstar T8MPN100F20A1 furnace and interchangeable across ICP-family furnaces (Heil, Comfortmaker, Arcoaire) that use the same 115V-to-24V 40VA control transformer. Verify the primary/secondary voltages and VA rating against your existing unit before installing.

Installation Guide

Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter.
Access — Remove the control compartment service panel.
Document — Photograph the primary and secondary wire connections before disconnecting.
Remove — Label and disconnect the leads, then unbolt the failed transformer from its mounting bracket.
Install — Mount the new transformer and reconnect the primary (line) and secondary (24V) leads per your photo.
Test — Restore power, confirm 24V at the secondary with a meter, and verify the thermostat powers up and the furnace responds to a call for heat.

Signs You Need a Replacement

Blank or dead thermostat with the furnace powered
No 24V control voltage measured at the board
Furnace does not respond to a heat call
Repeatedly blown control fuse or burnt transformer windings

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

Tempstar 40VA Transformer for T8...

$24.95

Frequently Asked Questions

Does this Transformer fit my Tempstar T8MPN100F20A1 Furnace — 115V to 24V | Ships Today?

Yes. This is the factory-specified OEM transformer for the Tempstar T8MPN100F20A1 Furnace — 115V to 24V | Ships Today. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.

How do I replace the transformer on my Tempstar T8MPN100F20A1 Furnace — 115V to 24V | Ships Today?

Difficulty: Medium (30–45 min)
Step 1: Turn off breaker. Step 2: Photo wiring connections. Step 3: Disconnect wires from old transformer. Step 4: Remove mounting hardware. Step 5: Install new transformer, reconnect wires matching voltage ratings. Step 6: Verify 24V output with multimeter.

My thermostat has no power. What failed?

Thermostat with no display = failed 24V transformer (or blown control board fuse). Check the 3A/5A fuse on the control board first ($1–$5 fix). If fuse is good but no 24V output from transformer, replace transformer.

Is this transformer compatible with Bryant or Payne too?

Many Tempstar parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.

Should I use OEM or aftermarket for my Tempstar transformer?

OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.

How fast does National HVAC Parts ship?

Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.

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