http://www.aaonnet.com/Default.aspx

http://www.acca.org/

http://www.aga.org/

http://www.airbalancingco.com/tutorial.html

http://www.air-conditioners-and-heat...ner_heater.htm

http://www.allthebrands.com/search.aspx?q=V%20Belt

Aprilairecontractors

http://www.ari.org/

http://www.avcoausa.com/products.htm

http://www.bacharach-training.com/

www.beckettcorp.com

http://www.blackbookoftools.com/

http://www.bookmarki.com/Mechanical-...-Books-s/6.htm

Building Science Corp.

www.burnham.com

http://businessownersideacafe.com

Carlyle Compressor

Carrier Technical Index (Index of Literature)

Carrier's Current Products

Carrier New and Old Product Search

Codes: www.iccsafe.org

http://www.contractingbusiness.com/

http://www.contractormag.com

http://www.cozyheaters.com/index.php

http://www.delavaninc.com/

www.delta-t.net/flow/pressure.htm

Digital Multimeter Basics http://www.idealindustries.com/tm/BasicsofDMMs.nsf

Dwyer

http://www.ebatts.com/

http://efficientcomfort.net/Calculators.html

http://efficientcomfort.net/jsp/DuctCalculator_Web.jsp

Efficient Indoor Comfort

www.elec-toolbox.com/main.html

www.electromn.com Link to a company that makes great load management products.

www.emersonclimate.com (Copeland compressor information)

Energy Star

www.engineeringtoolbox.com

http://www.epa.gov/iaq/pubs/airduct.html

http://ezinearticles.com/?Informaito...elts&id=427209

http://www.fieldcontrols.com/

http://www.flexibleduct.org/

http://fujitsugeneral.com/

http://www.galarson.com/MiscPages/LINKS.HTM

http://www.gamanet.org/gama/inforeso...y?OpenDocument

http://www.gates.com/catalogs/file_d...gates\catalogs

http://www.gates.com/catalogs/file_d...gates\catalogs

GE ECM: http://www.thedealertoolbox.com/ecmstore.php

Goodman Stuff...
http://partner.goodmanmfg.com/goodman/
username: goodman
password: dealer
click on "Toolkit" box
click on "infofinder"

www.grainger.com/Grainger/wwg/start.shtml

http://www.habmigern2003.info/

http://www.heatcraftrpd.com/service/support.asp (Great Info)

http://www.heil-hvac.com/productpages/pdx.html

Honeywell

www.customer.honeywell.com

http://www.hotwatt.com/mathconv.htm

Hoshizaki Ice Machine

http://www.hpac.com/

http://www.humidifirst.com/index.htm

https://hvacinstitute.ferris.edu/

www.hvac-pro.org FREE practice tests, T/P charts and more

http://www.hvactool.com/

http://www.hvactv.com/

www.hvacwebtech.com/HVACTechNotes.htm

http://www.iceomatic.com/servicedocumentation.asp

www.icpusa.com

http://johnmills.net/work/hvac2.html

http://johnmills.net/work/history.html History of HVAC Equipment

http://cgproducts.johnsoncontrols.co...opframe.aspx&0

JW Harris

Lama Books

http://www.lennoxcommercial.com/support/sign-in.asp (must register)

http://www.manitowocice.com/Service/ServiceLit.asp

http://www.mcnallyinstitute.com/home...per_index.html

http://www.mikeholt.com/index.php?id=homegeneral

http://www.mrslim.com/home.asp

http://www.natex.org

http://www.nationalcomfortinstitute.com/

Nesbitt

www.peakeind.com/docs/tshoot.htm

http://www.pelican-case.com/1400.html

Power Quality Basics http://www.idealindustries.com/pdf/P2110_short.pdf

psychrometric chart: http://www.handsdownsoftware.com/

http://www.rapidengineering.com/HVACLiterature.html

www.remichel.com

Renewaire

www.rheemote.net

www.rheemparts.com

http://www.rhvactools.com/

http://rses.org/main/index.cfm

http://www.scotsman-ice.com/general....ldownloads.xml

http://semiconductors.globalspec.com...ross_reference

http://www.slimduct.com/

SMACNA

snipsmag.com

http://www.sporlan.com/literature.shtm

http://www.superiorairducts.com/

www.tempstardlr.com

thesheetmetalshop.com

http://www.thermolec.com/aboutusen.htm

http://www.thermopride.com/

http://www.thermostatsusa.com/

http://trane.com/

http://www.udarrell.com/external_sta..._readings.html

www.uri.com

Useful Tech Support Numbers List...
http://hvac-talk.com/vbb/showthread.php?threadid=43047

http://visibledefects.com/

White-Rogers

York Residential

York Commercial

http://www.zero-zone.com/page.asp?page_id=12

http://4youradvantage.com/FreeFlatRatePricingBook.pdf

These link were provide courtesy of  
HVAC-talk.com