What are the specs for this Transformer?

The correct replacement for Tempstar model TNK125N20B1 — 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 TNK125N20B1 — 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 TNK125N20B1 — 115V to 24V | Ships Today

Name: Tempstar 40VA Transformer for TNK125N20B1 — 115V to 24V | Ships Today
Brand: Tempstar
SKU: 1011626-GEN
Price: 29.95 USD
Availability: InStock

SKU: 1011626-GEN Brand: Tempstar

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Overview

This genuine OEM control transformer (part number 1011626, TRANS 115>24 40VA S) supplies 24-volt control power for the Tempstar TNK125N20B1 gas furnace. It steps the 115V line voltage down to the 24V that runs the control board, thermostat, gas valve, and relays. A 40VA transformer provides ample capacity for the furnace control circuit. When a transformer fails — often from a shorted thermostat wire or a stuck contactor — the entire low-voltage system goes dead and the furnace will not respond to the thermostat at all.

Specifications

Spec	Value
Part Number	1011626
Type	Step-Down Control Transformer
Brand	Tempstar
Primary Voltage	115V
Secondary Voltage	24V
Rating	40VA
Fitment	OEM Direct-Fit

Compatibility

Designed for the Tempstar TNK125N20B1 furnace and shared Heil/ICP/Comfortmaker control assemblies using the same 40VA 115/24V transformer. Verify your unit's parts breakdown before ordering.

Installation Guide

Safety First — Disconnect power at the furnace switch and verify zero voltage with a multimeter.
Access — Remove the furnace control/service panel.
Document — Photograph the primary (line) and secondary (24V) wire connections before disconnecting.
Remove — Disconnect the leads, remove the transformer mounting screws, and lift out the old unit.
Install — Mount the new transformer and reconnect the primary and secondary leads exactly per your photo.
Test — Restore power and confirm 24V output and normal furnace operation.

Signs You Need a Replacement

No 24V control power — thermostat and furnace completely unresponsive.
Blown low-voltage fuse on the control board that re-blows.
Burnt smell or visibly charred transformer windings.
No voltage reading across the secondary terminals.

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...

$29.95

Frequently Asked Questions

Does this Transformer fit my Tempstar TNK125N20B1 — 115V to 24V | Ships Today?

Yes. This is the factory-specified OEM transformer for the Tempstar TNK125N20B1 — 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 TNK125N20B1 — 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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