
Combat® IDF-Series
Indirect-Fired Heating, Cooling and Ventilation Systems
■ Discharge air free of combustion by-products.
■ High e ciency due to three or four pass heat
exchanger design.
■ Longer part longevity: Motors, belts and bearings
are placed out of the airstream.
■ Rugged, heavy-duty construction: Unit cabinet
is supported by welded steel frame. Casing is
nish-coated to help protect against corrosion.
■ Modular design allows for custom
con gurations to meet customers' needs.
■ Evaporative and mechanical cooling
packages available.
Combat
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Combat® by Roberts-Gordon IDF-Series
COMBAT® by Roberts-Gordon IDF-Series air handlers improve indoor air quality and provide air comfort.
COMBAT® by Roberts-Gordon IDF-Series is one of the most versatile indirect- red heating systems. With three fuel
options, three control options, nine discharge choices, horizontal or upright installation, plus a complete line of air
handling and ltering accessories, COMBAT® by Roberts-Gordon IDF-Series is designed to last for years with proper
installation, maintenance and use.
MODEL IDF-35 IDF-45 IDF-50 IDF-65 IDF-75 IDF-85 IDF-100 IDF-125 IDF-150
CFM
Output
[MBH]*
MODEL IDF-175 IDF-200 IDF-225 IDF-250 IDF-275 IDF-300 IDF-350 IDF-400 IDF-450
CFM
Output
[MBH]*
3,500-
6,000
240-
350
13,000-
24,000
600-
1,750
3,500-
6,000
240-
450
21,000-
37,000
600-
2,000
4,000-
8,000
240-
500
21,000-
37,000
600-
2,250
4,000-
8,000
520-
650
21,000-
45,000
600-
2,500
6,000-
12,000
520-
750
21,000-
45,000
720-
2,750
6,000-
12,000
520-
850
30,000-
45,000
720-
3,000
6,000-
12,000
520-
1,000
35,000-
57,000
720-
3,500
10,000-
18,000
560-
1,250
35,000-
57,000
1,400-
4,000
13,000-
24,000
35,000-
57,000
* 1 MBH = 1,000 Btu/h
Model Con gurations
Outside
Air
Bottom
Discharge
Make-Up Air (MUA) Models
Design: 100% replacement air with a xed discharge air volume.
Function: Supplies direct replacement air for building mechanical exhaust.
Application: Used as make-up air for paint booths and other industrial
processes which incorporate mechanical exhaust.
560-
1,500
1,400-
4,500
Potentiometer Control
Bottom
Discharge
Pressure Gauge
Bottom
Discharge
Bottom
Return
Bottom
Return
Outside
Air
Outside
Air
Fixed Recirculation (FR) Models
Design: Manual modulation of outdoor air from 0% to 100% with use of
mixing box and potentiometer.
Function: Provides e cient, low-cost heating where minimum ventilation
rates are required.
Application: Used in warehouses, distribution centers, retail outlets, etc.
Air Management (AM) Models
Design: Automatic modulation of outdoor air from 0% to 100% with use
of mixing box and pressure gauge.
Function: Automatically responds to building pressure and temperature
needs.
Application: Used in industrial and commercial buildings that have air
quality and speci c air management requirements.

Combat® by Roberts-Gordon IDF-Series Features
Reliable, E cient System Operation Provided by:
• Double-width, double-inlet, forward-curved Class I,
AMCA rated centrifugal fan.
• System that does not contaminate heated air with
combustion by-products.
• Operation of fan only in warm weather to enjoy free
ventilation cooling.
• Full- oating, stainless steel primary heat exchanger.
• Multiple blowers on tubular steel blower shafts (on
most models).
• Mounting and wiring of all necessary operating
starters, relays, switches, safety controls and fuses.
• Variable pitch drive pulley (up through 10 hp).
• ODP motors with adjustable motor mounts.
Long Lasting Construction Provided by:
• Rugged angle steel base frame on every unit section
to withstand the rigors of shipping and handling.
• Fabricated sheet panels that virtually eliminate
rattling or rumbling.
• Extra long life, self-aligning bearings sized for
industrial duty.
• White painted nish.
• Double-wall heat exchanger module.
Other IDF-Series Options:
• Natural gas, propane gas or oil burners available.
• Roof curbs and vertical stands simplify mounting.
• Fresh air hood with birdscreen helps protect against
water entrainment.
• V-bank lter section with disposable or cleanable
lters for longer equipment life of internal
components.
• Motorized two-position inlet or discharge damper
for ex ltration control.
• Gas trains approved to FM, IRI, or other special code
requirements.
• Insulated and/or weatherized sections available for
outdoor units.
IDF-Series Controls’ Options:
• Remote Station with room or discharge thermostat
for easy operation and remote temperature
adjustment.
• UL listed.
• Audible alarm for ame failure.
• Clogged lter indicator.
• Service Receptacle.
• Unit-mounted on/o toggle switch.
Ease of Maintenance Provided by:
• Modular designed sections.
• Convenient access to heat exchangers and blower
module for eld service.
• Optional service platforms on upright units.
®
Combat
by Roberts-Gordon IDF-Series Optional Cooling Packages
Evaporative Cooling
COMBAT® by Roberts-Gordon IDF-Series evaporative cooling system is an economical cooling solution. It requires no aircooled condenser, no chiller or cooling tower, no chilled water pumps or distribution piping/insulation, no major motor control
center or electrical gear. Operating costs are a fraction of similar-capacity mechanical refrigeration systems.
Evaporative cooling works when warm air passes over specially treated wetted media. The heat passes from the air to the
wetted media, causing the water to evaporate and inside air to cool.
Mechanical Cooling
For situations requiring temperature and humidity levels lower than the performance parameters available with outdoor air
alone or with evaporative cooling, COMBAT® by Roberts-Gordon IDF-Series o er a broad range of cooling options.
Cooling options can be added by simply installing coil sections equipped with the appropriate cooling coils and a condensing
unit or chiller. The versatility a orded by the coil section enables you to utilize DX refrigerant, chilled water or other types of
cooling coils in your system.

Discharge Options
Horizontal Unit/Horizontal Discharge Upright Unit/Top Left Discharge Upright Unit/Bottom Left Discharge
OA/RA
DA
DA
OA/RA
DA
OA/RA
Horizontal Unit/Bottom Discharge Upright Unit/Top Right Discharge Upright Unit/Bottom Right Discharge
OA/RA
DA
OA/RA
DA
OA/RA
DA
Horizontal Unit/Top Discharge Upright Unit/Top Discharge Upright Unit/Bottom Discharge
DA
OA/RA
DA
OA/RA
OA/RA
DA
LEGEND
OA = Outside Air DA = Discharge Air RA = Return Air
Installation Code and Annual Inspections:
All installations and service of ROBERTS GORDON
service of products sold and supplied by Roberts-Gordon and conform to all requirements set forth in the ROBERTS GORDON
manuals and all applicable governmental authorities pertaining to the installation, service and operation of the equipment. To help
facilitate optimum performance and safety, Roberts-Gordon recommends that a qualifi ed contractor annually inspect your ROBERTS
GORDON
Further Information: Applications, engineering and detailed guidance on systems design, installation and product performance is
available through ROBERTS GORDON
Installation, Operation and Service Manual.
This product is not for residential use.
This document is intended to assist licensed professionals in the exercise of their professional judgement.
Roberts-Gordon, LLC
1250 William Street
P.O. Box 44
Bu alo, NY 14240-0044 USA
Telephone: 716.852.4400
Fax: 716.852.0854
Toll Free: 800.828.7450
www.rg-inc.com
© 2007 Roberts-Gordon, LLC All rights reserved. No part of this work covered by the copyrights herein may be reproduced or copied in any form or by any means
– graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems –
without written permission of Roberts-Gordon, LLC.
Printed in U.S.A. CIDFBNA 5M 0207 Rev A
®
products and perform service where necessary, using only replacement parts sold and supplied by Roberts Gordon.
®
representatives. Please contact us for any further information you may require, including the
®
products must be performed by a contractor qualifi ed in the installation and
European O ce:
Roberts Gordon Europe Limited
Telephone: +44(0) 1902 494425
Fax: +44(0) 1902 403200
®