What are the specs for this Transformer?

The correct replacement for Tempstar model TNE125J20G1 — 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 TNE125J20G1 — 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 TNE125J20G1 — 115V to 24V | Ships Today

Name: Tempstar 40VA Transformer for TNE125J20G1 — 115V to 24V | Ships Today
Brand: Tempstar
SKU: 1012722-GEN
Price: 29.00 USD
Availability: InStock

SKU: 1012722-GEN Brand: Tempstar

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Overview

This OEM Tempstar control transformer (part 1012722) steps incoming line voltage of 115V down to the 24V low-voltage control circuit that powers the thermostat, gas valve, relays, and ignition control on your furnace. Rated at 40VA, it supplies the steady, regulated control power your system needs to operate safely. When a transformer fails, the entire low-voltage circuit goes dead: the thermostat screen blanks, the furnace will not respond to a call for heat, and you may notice a tripped fuse or a faint burnt smell. A buzzing transformer or one that is hot to the touch is on its way out.

Specifications

Spec	Value
Part Number	1012722
Type	Control / Step-Down Transformer
Brand	Tempstar
Rating	40 VA
Primary Voltage	115V
Secondary Voltage	24V

Compatibility

Direct OEM fit for the Tempstar TNE125J20G1 and other ICP / Tempstar / Heil air handlers and furnaces that use a 115V-to-24V 40VA control transformer. Always confirm your existing transformer's primary and secondary voltages and VA rating before installing.

Installation Guide

Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter.
Access — Remove the furnace service panel to reach the control area.
Document — Photograph all primary and secondary wire connections before disconnecting.
Remove — Disconnect the line-voltage primary leads and the 24V secondary leads, then unbolt the failed transformer from the panel.
Install — Mount the new transformer, then reconnect the primary and secondary wiring exactly per your photo.
Test — Restore power and confirm 24V across the secondary and normal system operation.

Signs You Need a Replacement

Thermostat is blank or dead with no low-voltage power
Furnace will not start on a call for heat
Repeated blown low-voltage fuses
Transformer buzzes, runs hot, or smells burnt

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 TN...

$29.00

Frequently Asked Questions

Does this Transformer fit my Tempstar TNE125J20G1 — 115V to 24V | Ships Today?

Yes. This is the factory-specified OEM transformer for the Tempstar TNE125J20G1 — 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 TNE125J20G1 — 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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