What are the specs for this Transformer?

The correct replacement for Arcoaire model AG100–AG250 Series — 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 Arcoaire equipment which lists the model number AG100–AG250 Series — Ships Today.

Is this transformer compatible with Bryant or Payne systems too?

Many Arcoaire 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.

Arcoaire

Arcoaire 40VA Transformer 208/240V to 24V for AG100–AG250 Series — Ships Today

Name: Arcoaire 40VA Transformer 208/240V to 24V for AG100–AG250 Series — Ships Today
Brand: Arcoaire
SKU: 79471
Price: 44.20 USD
Availability: InStock

SKU: 79471 Brand: Arcoaire

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Overview

The Arcoaire 79471 (OEM cross AT72H1002) is a 40VA control transformer that steps 208/240V line voltage down to 24V to power the furnace control board, gas valve, and thermostat circuit across the AG series. The transformer supplies every low-voltage control component — when it opens or shorts, the furnace loses all 24V power and will not start, leaving the thermostat dark and the system unresponsive. The typical failure is a shorted secondary from a grounded control wire that overheats and burns out the windings. A correctly rated 40VA OEM replacement restores reliable control-voltage power and proper furnace operation.

Specifications

Spec	Value
Part Number	79471
OEM Cross	AT72H1002
Type	Step-Down Control Transformer
Brand	Arcoaire (ICP)
Rating	40 VA
Primary Voltage	208 / 240V
Secondary Voltage	24V
Fits Models	AG100, AG130, AG170, AG200, AG250

Compatibility

Direct OEM replacement for Arcoaire AG100, AG130, AG170, AG200, and AG250 furnaces. Verify your primary voltage tap and VA rating before installing.

Installation Guide

Safety First — Disconnect power at the furnace switch and verify zero voltage with a multimeter.
Access — Remove the control compartment service panel.
Document — Photograph all primary and secondary leads before disconnecting.
Remove — Disconnect the leads, remove the mounting hardware, and pull the old transformer. Check the low-voltage wiring for shorts before energizing the replacement.
Install — Mount the new transformer, land the primary on the 208 or 240V tap to match your supply, and reconnect the 24V secondary per your photo.
Test — Restore power, confirm 24V at the secondary with a multimeter, and verify the controls energize on a call.

Signs You Need a Replacement

Furnace completely dead with no 24V control power
Repeatedly blown low-voltage control fuse
Overheated, buzzing, or discolored transformer
No measurable voltage at 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

Arcoaire 40VA Transformer 208/24...

$44.20

Frequently Asked Questions

Does this Transformer fit my Arcoaire AG100–AG250 Series — Ships Today?

Yes. This is the factory-specified OEM transformer for the Arcoaire AG100–AG250 Series — 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 Arcoaire AG100–AG250 Series — 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 Arcoaire 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 Arcoaire 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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