What are the specs for this Transformer?

The correct replacement for Tempstar model T8DNL100L20B2 — 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 T8DNL100L20B2 — 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 T8DNL100L20B2 — 115V to 24V | Ships Today

Name: Tempstar 40VA Transformer for T8DNL100L20B2 — 115V to 24V | Ships Today
Brand: Tempstar
SKU: 1172810-GEN
Price: 26.95 USD
Availability: InStock

SKU: 1172810-GEN Brand: Tempstar

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Overview

This is a genuine OEM 40VA control transformer (part number 1172810) for the Tempstar T8DNL100L20B2 gas furnace. It steps down 115V line voltage to the 24V control circuit that powers the thermostat, gas valve, hot surface igniter circuit, and control board. The 40VA rating provides adequate current for every low-voltage component to operate at once. A failed transformer kills the entire low-voltage side of the furnace: the thermostat goes blank, the unit ignores calls for heat, and no 24V can be measured at the board. Buzzing, a repeatedly blown control fuse, or a scorched smell at the control box typically precede a complete failure.

Specifications

Spec	Value
Part Number	1172810
Type	Step-Down Control Transformer
Brand	Tempstar
Rating	40 VA
Primary Voltage	115V
Secondary Voltage	24V
Application	Gas Furnace Control Circuit

Compatibility

Direct-fit replacement for the Tempstar T8DNL100L20B2 furnace and shared across many ICP-family platforms (Tempstar, Heil, Comfortmaker, Arcoaire) using the same 115V-to-24V 40VA control transformer. Confirm the printed part number and lead configuration on your existing transformer before installing.

Installation Guide

Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter.
Access — Remove the furnace control panel / blower compartment door to reach the control box.
Document — Photograph the 115V primary and 24V secondary wire connections before disconnecting.
Remove — Disconnect the leads, remove the mounting screws or bracket, and lift out the failed transformer.
Install — Mount the new transformer and reconnect the line and load leads exactly per your photo.
Test — Restore power, confirm 24V at the secondary terminals, and run a full heat cycle.

Signs You Need a Replacement

Blank thermostat and no furnace response on a call for heat.
No 24V at the secondary terminals or control board.
Repeatedly blown low-voltage control fuse.
Buzzing noise or burnt odor from the transformer.

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...

$26.95

Frequently Asked Questions

Does this Transformer fit my Tempstar T8DNL100L20B2 — 115V to 24V | Ships Today?

Yes. This is the factory-specified OEM transformer for the Tempstar T8DNL100L20B2 — 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 T8DNL100L20B2 — 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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