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Harmonic Heating & Air Conditioning is here to take care of all your comfort system maintenance, repair and installation needs! Call us when you need comfort services!

Harmonic Heating & Air Conditioningstarstarstarstarstar4.9 / 5

221 Total Reviews /files//harmonic-logo-footer.png630-999-9008$10S187 Schoger Dr Suite #54, Naperville IL

ES2 Chimney Vented Cast Iron Boiler

The cast iron heat exchanger is the heart of these boilers. It is manufactured in Zanesville' Ohio and is designed for years of reliable service. Each heat exchanger is water and pressure tested prior to assembly. The boilers themselves are built in Lancaster' PA. Every component used in the IQ family of boilers is subject to strict standards of quality control and performance verification which are used throughout the manufacturing process.

  • 85% AFUE
  • Electronic Ignition
  • Easy' intelligent IQ Control System™
  • Outdoor reset available – increases efficiency by 15-20%
  • Reliable' American-made cast iron heat exchanger accepts return water as low as 110°F
  • IQ Control System Combines aquastat' relay' and ignition functions into a single module
  • IQ Option Panel Enables the easy plug & play installation of optional features such as outdoor reset' LWCO' and high limit
  • Optional Touchscreen LCD displays all boiler settings' diagnostics' and troubleshooting in sentences' not codes
MODELInput MBtuHOutput MBtuHAFUEDimensions
Water Content
ES2-370.0 59.0 85.0 41x12.75x33 2.00 254
ES2-4105.0 89.0 85.0 41x15.5x33 3.00 301
ES2-5140.0 119.0 85.0 41x18.5x33 4.00 353
ES2-6175.0 149.0 85.0 41x21.5x33 5.00 405
ES2-7210.0 178.0 85.0 41x24.75x33 6.00 464
ES2-8245.0 208.0 85.0 41x27.75x33 7.00 514
ES2-9280.0 238.0 85.0 41x30.75x33 8.00 564

Warranty Information

  • All Parts for 12 months -
  • Heat Exchanger - Limited Lifetime

Available Documents


We customize your comfort by making your home smarter, healthier and more efficient. Your peace of mind is as important to us as your comfort.

That's why every product us backed by warranties as robust and dependable as the products themselves.

Every piece of heating & cooling equipment is eligible for a 12-Year Parts Warranty, when you join the "Rock*Star Maintenance Program".

All other products are eligible for the 12-Year Parts Warranty.

Ask for details, terms, and conditions. All product warranties are registered by Harmonic within 30 days of purchase.

on all equipment repairs, indoor air quality & comfort items

Including humidifiers, air filters, air cleaners, thermostats and more! 12 year parts and labor warranty requires joining Rock*Star Maintenance Program. Ask for details, terms, and conditions.

The "Exclusive 12-year Parts & Labor Warranty" covers parts and labor cost from the time of purchase. "Exclusive 12-year Parts & Labor Warranty" requires annual maintenance to be performed by Harmonic Heating & Air Conditioning beginning immediately from the time of purchase. Maintenance must be performed annually during the initial 12-year coverage term in order to uphold warranty status. If annual maintenance is missed or not performed by Harmonic Heating & Air Conditioning, the "Exclusive 12-year Parts & Labor Warranty" becomes void immediately. Warranty coverage defaults to a 10 year part warranty and a 2 year labor warranty from the time of purchase. Warranty is registered to the purchaser and is not transferable.


when you purchase a Furnace or Air Conditioner from Harmonic!