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AIR HANDLER / BLOWER UNITS
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BACKDRAFTING HEATING EQUIPMENT
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CIRCULATOR PUMPS & RELAYS
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COOL OFF HEAT, Thermostat Switch
DEFINITION of HEATING & COOLING TERMS
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FAN CONVECTOR HEATERS - HYDRONIC COILS
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HEATING LOSS DIAGNOSIS-BOILERS
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HEATING SYSTEM INSPECT DIAGNOSE REPAIR
LOW VOLTAGE BUILDING WIRING
LOW VOLTAGE TRANSFORMER TEST
MANUALS & PARTS GUIDES - HVAC
NO HEAT - BOILER
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ODORS FROM HEATING SYSTEMS
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PULSE COMBUSTION HEATERS
Reset Switch - Heater Primary Control
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STEAM HEATING SYSTEMS
THERMOSTATS, HEATING / COOLING
THERMOSTATS, WATER HEATER
THERMOSTATIC EXPANSION VALVES
ZONE VALVES, HEATING
Thermostat wiring connections for the Azel i-Link multi-zone switching relay used to control HVAC equipment. This article gives a table showing the proper wire connections for the Azel i-Linkroom thermostat used to control heating or air conditioning equipment. Other thermostat wiring schematics are provided by this article series and are listed at THERMOSTAT WIRING CONNECTION TABLES.
Room thermostat installation & wiring guide: this article series explains the basics of wiring connections at the thermostat for heating, heat pump, or air conditioning systems. Our page top sketch, courtesy of Honeywell Controls, illustrates the wiring diagram for a traditional Honeywell T87F thermostat used for 2-wire single pole single throw control of heating only in a typical gas-fired heating system.
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In a radiant floor heating system that uses a controller, the additional thermostats must be wired to instruct that controller to send heat to their zones. Azel Technologies, a Canadian heating controller manufacturer, provides installation instructions and wiring diagrams for their controllers, including the Azel i-Link SP83-here is a copy.
Or contact Azel Technologies Inc., P.O. Box 53138 10 Royal Orchard Blvd. Thornhill, Ontario, Canada L3T 7R9 Ph: 905-223-5567 Fax: 905-223-3778 Email: firstname.lastname@example.org, Website: www.azeltec.com.
Reader Question: 3-zone radiant heat: Honeywell RHT2300B thermostat can't talk to Azel i-Link SP83 zone controller
I am installing a 3 zone in-floor radiant system in my home. Every thing is going well so far, except I am running into an issue where Honeywell (my T-Stat manufacture) is telling me my RHT2300B t-stat cannot be used with my in-floor zone controller (Azel i-Link sp-83) when I call their tech support hotline.
They cannot tell me why or what their letter designations mean.
I am an industrial controls electrician of 23 years, who I must confess, does not have much experience with HVAC.
All I need is a simple t-stat that sends voltage (24vac) when heat is called for to my controller and opens back up (back to zero volts) when the set-point is achieved. I am having a hard time believing that this t-stat is not capable of doing that. Can any one help?
Reply: get the thermostat and controller product numbers correct and it's easy to find wiring instructions
I found two important details in researching your question:
1. you gave me an in-valid Honeywell thermostat number, but I was able to guess at the correct one and easily obtain wiring instructions from Honeywell. Correctly your thermostat is the Honeywell 5-2 Day Programmable Thermostat - RTH2300B1012
2. For the Honeywell thermostat model that you mention, correctly named, Honeywell's instructions point out that
Call back and ask for senior service tech or service manager. So if, when you spoke with the Honeywell service technician, and if your old thermostat included and used any two of the wire labels I quote above, then indeed, even if s/he couldn't explain why, indeed you cannot use this thermostat model for your application.
Wiring details for the Honeywell 5-2 Day Programmable thermostat are found at Honeywell Thermostat Wiring Guides
We provide thermostat wiring connections for just about every type of residential heating or cooling room thermostat as well as a description of thermostat wiring color codes & conventions. At THERMOSTAT INSTALLATION STEPS we provide a step by step photo guide to installing a room thermostat. We also provide THERMOSTAT WIRING DIAGRAMS and a separate explanation of THERMOSTAT WIRE FUNCTIONS or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
Question: Replacing a round Honeywell T87 with a Digital Honeywell Thermostat
Hello - I am replacing a round Honeywell thermostat with a non-programmable digital Honeywell unit. I have a hot water system with multiple zones and with no air conditioning. There are three wires at the thermostat. On the old round unit the red wire went to the R terminal, the white wire went to the w terminal and a green wire went to B terminal. I hooked up the new stat the same way but it would not work. If I selected "fan on" instead of "fan auto" the zone would heat up but would not shut off (hot water kept flowing even if I selected a temp below room temp). Appreciate your help. - Patrick - 1/20/12
Patrick, typically the three wire thermostat hookups would be exactly the same for the old and new thermostats.
For details of wiring a typical and simple digital Honeywell thermostat, see Honeywell 5-2 Day Programmable Thermostat - RTH2300B1012.
For help in understanding the wiring of your old thermostat, see Three-Wire Honeywell Wall T87-F type Thermostat wiring and also see Generic HVAC Thermostat Control Wiring Points
Question: Replacing a mercury thermostat with a digital unit
I am replacing an old mercury thermostat with a digital. my system is a heat pump. my neighbor gave me the digital, no instructions, no box. i'm trying to decide if this is even a heat pump compatible thermostat. on the therm it has c, g, rc, rh (which are linked by a black wire.) w, y, b, and o. coming out of my wall is, white connected on old therm w2, yellow connected to y, green conn g, black conn e, red to r, blue to b and bro to x. any help would be great. - Kurt 6/4/12
Kurt, as you see in the examples at For help in understanding the wiring of your old thermostat, see Three-Wire Honeywell Wall T87-F type Thermostat wiring and also see Generic HVAC Thermostat Control Wiring Points. Many thermostat wiring setups are straightforward or "cookbook" but why not find the brand name on your thermostat and then you can obtain the installation instructions right from the manufacturer?
Also, Honeywell's thermostat replacement advice (and most likely that of all thermostat manufacturers) warns:
Watch out: MERCURY NOTICE: Do not put your old thermostat in the trash if it contains mercury in a sealed tube. Contact your local waste management authority for instructions regarding recycling and proper disposal.
Questions & answers or comments about heating, air conditioning, and heat pump thermostat installation and wiring
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