InspectAPedia.com InspectAPedia®
Google
InspectAPedia
 

Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair

Ask a Question or Search InspectAPedia

  • HOME
  • AIR CONDITIONING
  • ELECTRICAL
  • EXTERIORS
  • HEATING
  • HOME INSPECTION
  • INTERIORS
  • PLUMBING
  • ROOFING
  • SEPTIC SYSTEMS
  • STRUCTURE
  • WATER SUPPLY
  • ENERGY SAVINGS
  • ENVIRONMENT
  • INDOOR AIR IAQ
  • INSULATION
  • MOLD INSPECT TEST REMOVE
  • NOISE
  • ODORS
  • SOLAR ENERGY
  • VENTILATION
  • EXPERTS DIRECTORY
  • CONTACT US



Mobile Phone or PDA view of this websiteMobile View
HEATING SYSTEMS

AFUE DEFINITION, RATINGS
AGE of CHIMNEYS & FIREPLACES
AGE of AIR CONDITIONERS & HEAT PUMPS
AGE of FOUNDATION MATERIALS
AGE of FRAMING MATERIALS
AGE of FLOORING MATERIALS
AGE of ELECTRICAL WIRING
AGE of HEATERS, BOILERS, FURNACES
AGE of WATER HEATERS
AIR CONDITIONING & HEAT PUMP SYSTEMS
AIR FILTERS for HVAC SYSTEMS
ANODES & DIP TUBES on WATER HEATERS

AIR HANDLER / BLOWER UNITS
AIRBOUND HEAT SYSTEM REPAIRS
ANODES & DIP TUBES on WATER HEATERS
ANTI SCALD VALVES
APPLIANCE EFFICIENCY RATINGS
ASBESTOS IDENTIFICATION IN buildings

BACKDRAFTING HEATING EQUIPMENT
BACKFLOW PREVENTERS
BAROMETRIC DAMPERS
BASEBOARD HEAT

BIOGAS PRODUCTION & USE
BLEVE EXPLOSIONS
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BLUE vs YELLOW COMBUSTION FLAMES
BLUERAY Recall

BOILERS, HEATING
  BOILER CONTROLS & SWITCHES
  Air Bleeder Valves
  Air Scoops Purgers Separators
  AQUASTAT CONTROL Functions
  Boiler Pressure Controls & Settings
  CAD CELL RELAY SWITCH
  CHECK VALVES, HEATING SYSTEM
  Chemical treatments, Boiler
  Circulator Pumps & Relays
  DIAGNOSE & FIX BOILER
  DRAFT REGULATORS, BAROMETRIC DAMPERS
  ELECTRIC MOTOR OVERLOAD RESET SWITCH
  ELECTRICAL POWER SWITCH FOR HEAT
  Expansion Tanks
  FIRE SAFETY CONTROLS
  Gauges on Heating Equipment
  Limit Switches, Boilers
  Low Water Cutoff Valves, Boilers
  MIXING / ANTI-SCALD VALVES
  OIL LINE QUICK STOP VALVES
  OIL LINE SAFETY VALVES
  Pressure Gauges, Boilers
  Pressure & Temperature Settings, Controls
  RELIEF VALVES - TP VALVES
  Reset Switch - Primary Control
  Reset Switch - electric motors
  SPILL SWITCHES
  STACK RELAYS
  THERMOSTATS, HEATING / COOLING
  Water Feeder Valves, Hydronic Boiler
  Zone Valves

BOILER LEAKS CORROSION STAINS
BOILER LEAKS, HOW TO LOCATE
BOILER NOISE SMOKE ODORS
BOILER OPERATING PROBLEMS
BOILER OPERATION DETAILS
BOILER PRESSURE & TEMPERATURE SETTINGS
BOOKSTORE - InspectAPedia
BUILDING SAFETY HAZARDS GUIDE

CAPACITORS for HARD STARTING MOTORS
CARBON DIOXIDE - CO2
CARBON MONOXIDE - CO
CARBON MONOXIDE WARNING

CHIMNEY INSPECTION DIAGNOSIS REPAIR
CHIMNEYS & Flues - Asbestos Transite Pipe
CHINESE DRYWALL HAZARDS
CIRCULATOR PUMPS & RELAYS
COOL OFF HEAT, Thermostat Switch

COMBUSTION AIR
COMBUSTION AIR for TIGHT buildings
COMBUSTION GASES & PARTICLE HAZARDS
COMBUSTION PRODUCTS & IAQ
COMPLETE COMBUSTION, Stoichiometric
CREOSOTE FIRE HAZARDS

CONDENSING BOILERS/FURNACES
CONDENSING BOILERS/FURNACES DAMAGE
CONVECTOR HEATERS - HYDRONIC COILS

DEFINITION of Heating & Cooling Terms
DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DIRECT VENTS / SIDE WALL VENTS
DIRECTORY of OIL TANK EXPERTS
DRAFT HOODS - gas fired
DRAFT MEASUREMENT, CHIMNEYS & FLUES
DRAFT REGULATORS, DAMPERS, BOOSTERS
DUCT SYSTEM & DUCT DEFECTS
DUST CONTAMINATION FROM HVAC?

ELECTRIC HEAT, DIAGNOSIS, REPAIR
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRICAL POWER SWITCH FOR HEAT
EVAPORATIVE COOLING SYSTEMS

FAN, AIR HANDLER BLOWER UNIT
FAN AUTO ON Thermostat Switch
FAN, COMPRESSOR/CONDENSER UNIT
FAN CONVECTOR HEATERS - HYDRONIC COILS
FAN LIMIT SWITCH
FAN NOISES

FILTERS, AIR for HVAC SYSTEMS
FILTERS, OIL on HEATING EQUIPMENT

FIRE SAFETY CONTROLS
FIREPLACES & HEARTHS
FLAME COLOR, BLUE vs YELLOW COMBUSTION
FLOODED HEATING EQUIPMENT REPAIR
FLOODED WATER HEATER REPAIR
FLUE VENT CONNECTORS
FREEZE-PROOF A BUILDING
FUEL OIL TYPES & CHARACTERISTICS
FUEL UNIT, HEATING OIL PUMPS

FURNACES, HEATING
FURNACE CONTROLS & SWITCHES
FURNACE EFFICIENCY, HIGH vs MID
FURNACE HEAT EXCHANGER LEAKS
FURNACE OPERATION DETAILS
FURNACE OPERATING TEMPERATURES

GALVANIC SCALE & METAL CORROSION
GAS BURNER Flame & Noise Defects
GAS FIRED WATER HEATERS
GAS PIPING, VALVES, CONTROLS
GAUGES ON HEATING EQUIPMENT
GEOTHERMAL HEATING SYSTEMS

HEAT EXCHANGER LEAKS
HEAT LOSS in buildings
HEAT LOSS DETECTION TOOLS
HEAT LOSS INDICATORS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION
HEAT PUMPS, DiAGNOSIS, REPAIR
HEAT TAPES & CABLES on Roofs for Ice Dams

HEATING COST FUEL & BTU Cost Table
HEATING COST SAVINGS METHODS
HEATING LOSS DIAGNOSIS-BOILERS
HEATING LOSS DIAGNOSIS-FURNACES
HEATING OIL CLOUD WAX GEL POINT
HEATING OIL EXPOSURE HAZARDS, LIMITS
HEATING OIL - OLD, USEABLE?
HEATING OIL PIPING TROUBLES
HEATING OIL SHELF LIFE
HEATING OIL SLUDGE
HEATING OIL USAGE RATE
HEATING SMALL LOADS
HEATING SYSTEM INSPECT DIAGNOSE REPAIR
HEATING SYSTEM INSPECTION DETAILS
HEATING SYSTEM NOISES
HEATING SYSTEM TYPES

HIGH EFFICIENCY BOILERS/FURNACES

HOT WATER HEATERS
HOT WATER IMPROVEMENT

INSULATION INSPECTION & IMPROVEMENT

LP & Natural Gas Safety Hazards

MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
MOTOR OVERLOAD RESET SWITCH

Natural Gas Combustion Products
NO HEAT - BOILER
NO HEAT - FURNACE
NOISE / SOUND DIAGNOSIS & CURE
NOISE AIR CONDITIONER / HEAT PUMP
NOISE, DUCT VIBRATION DAMPENERS
NOISE, HEATING SYSTEMS
NOISE, PLUMBING
NOISE, WATER HEATER

ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS FROM HEATING SYSTEMS

OIL BURNERS
OIL BURNER FUEL UNIT
OIL BURNER INSPECTION & REPAIR
OIL BURNER NOISE SMOKE ODORS
OIL BURNER NOZZLE & ELECTRODES
OIL BURNERS, RETENTION HEAD
OIL BURNER SOOT & PUFFBACKS

OIL FILTERS on HEATING EQUIPMENT
OIL FILTER MISSING
OIL FUEL TYPES & CHARACTERISTICS
OIL & GAS PIPING
OIL LINE CLOGGING FIX
OIL LINE QUICK STOP VALVES
OIL LINE SAFETY VALVES
OIL ODORS, LEAKY OIL TANK PIPING
OIL PUMP FUEL UNIT
OIL SPILL CLEANUP / PREVENTION
OIL TANKS
OIL TANK GAUGES
OIL TANK PIPING & PIPING DEFECTS
OIL TANK SAFETY
OIL TANK SLUDGE
OIL TANK TESTING
OIL TANKS, BURIED
OIL TANK WATER REMOVAL

PLASTIC HEATER VENT
PULSE COMBUSTION HEATERS
PASCAL CALCULATIONS

RADIANT BARRIERS
RADIANT HEAT
RADIANT HEAT Floor Mistakes to Avoid
RADIANT HEAT TEMPERATURES
RADIANT SLAB FLOORING CHOICES
RADIANT SLAB TUBING & FLUID CHOICES

RADIATORS

RELIEF VALVES - TP Valves on Boilers
RELIEF VALVES - STEAM TP VALVES
RELIEF VALVES - Water Heaters
RELIEF VALVES - Water Tanks

Reset Switch - Heater Primary Control
Reset Switch Broken - Quick Repair
Reset Switch - Electric Motors
Reset Switch - Stack Relays

SAFETY HAZARDS & INSPECTIONS
SAFETY HAZARDS GUIDE
SAFETY, HEATING INSPECTION
SAFETY,HOME HEATING TIPS
Safety Recalls, Chimneys, Vents, Heaters
SOLAR HEATING SYSTEM DESIGNS
SOOT on OIL FIRED HEATING EQUIPMENT
SPILL SWITCHES - Flue Gas Detection
SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS
STACK RELAY SWITCHES
STAIN DIAGNOSIS on BUILDING INTERIORS

STEAM HEATING SYSTEMS

TANKLESS COILS
THERMAL EXPANSION of MATERIALS
THERMAL MASS in buildings
THERMAL TRACKING & HEAT LOSS
THERMOSTATS, HEATING / COOLING
Transite Pipe Chimneys & Flues

VIDEO GUIDES: Heating System Videos
VIDEO GUIDES - InspectAPedia.com

WATER HEATERS
WATER HEATER SAFETY
WATER HEATERS for HOME HEATING USE?
WATER HEATER NOISES
WATER HEATER SCALE - De-Liming Procedure
WATER HEATER SCALE PREVENTION
WINTERIZE A BUILDING
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY

ZONE VALVES

More Information

LARGER VIEW of a heating boiler cad cell relay switchGuide to Heating System Boiler Zone Valve Controls
InspectAPedia®  -      

  • Zone Valves on hot water heating systems
  • Zone valves on indirect domestic hot water heaters
  • What is a motorized zone valve on a hot water heating system?
  • How do heating zone valves work, how do we inspect, repair, install them?
  • Questions & answers about zone valves on hot water heating systems: installation, diagnosis, repair advice

Zone valves on hot water heating systems: what is a zone valve, how do they work, and how do I troubleshoot, install, repair or replace a zone valve? This website answers most questions about Heating System Boiler Controls on central heating systems to aid in troubleshooting, inspection, diagnosis, and repairs. The photo above shows a a bank of six zone valves controlling heat distribution in a large home.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Explanation of Zone Valves on Heating Boilers - Controlling Hot Water Heat

Honeywell heating zone valve

Our photo at left shows a Honeywell (TM) zone valve installation.

Heating water piping in a building, particularly where hot water baseboard heat is used, may be divided into separate heating zones (different floors, or different areas on a single floor) to permit more detailed control of heat distribution in a building.

The control of heating water through these different heating zones may be accomplished by use of zone valves (one per heating zone or area or "loop" of heating piping) which in turn are connected to individual thermostats.

When the thermostat calls for heat in a particular building area, the thermostat switch causes the zone valve to open, to permit hot water to flow through that zone.


Zone valve

Other brands of zone valves such as those made by Flair (TM) (problem prone), and White Rodgers work similarly but their wiring may be slightly different.

In all cases, when the zone valve is fully open, an "end switch" inside the valve tells the heating system's circulator to begin operating, causing hot water to flow through the zone.


Heating zone valve with cover off

Typically heating systems using zone valves will have two or more zone valves (usually but not always located close to the heating boiler) and a single circulator pump (usually located on the return end of the hot water piping close to the heating boiler).

But if you see a zone valve with the cover off (photo at left) that may be a clue that the valve has been having problems with jamming or sticking - someone left the cover off to try to keep the valve a little cooler.

Good installation details install a zone valve on the return side of the heating piping loop where it will be exposed to lower and thus less stressful temperatures.

Zone Valve Defects to Watch For

Zone Valve manual control lever (C) Daniel Friedman

  • Zone valve does not work - jammed, stuck, does not open in response to call for heat at that zone. Provided the wiring and thermostat are correct and operating, if no hot water flows past the valve on a call for heat (feel the pipes for heat) it may be jammed and need replacement

    Our photo (left) shows the manual control valve in its "automatic" or normal position on a Honeywell™ heating zone control valve.
  • Zone valve is leaking - leaky zone valves will stop working soon and need replacement
  • Zone valves installed on the hot side or boiler-out side of the heating piping loop, exposing the valve to higher and more stressful temperatures
  • Zone valve with covers off - may indicate overheating and jamming
  • Zone valve with its manual lever left in the manual "on" position - may indicate that the valve does not work - this zone is forced into "always on" status

LARGER VIEW of a heating boiler cad cell relay switchOlder models of some zone valves such as these Flair™ valves are perhaps more likely to be "stuck" either open (you'll have heat in that zone) or shut (that zone won't heat).

For details about the setting, re-setting, or function of the controls and switches commonly found on hot air heating systems see these articles:

  • Hot Air Heating Furnace Basic Operating Steps
  • Guide to Heating System Components:
  • Air Bleeder Valves for Hot Water Heating Systems: Radiators, Baseboards, Convectors
  • Aquastats Heating Boiler Primary Controls: A guide to Aquastats for control of hot water heating boilers and tankless coils
  • BLUE vs YELLOW COMBUSTION FLAMES - the Blueray history and blue flame vs. yellow flame combustion, flame color & combustion efficiency, & how oil competes with gas as a heating fuel.
  • CAD CELL RELAY SWITCH on oil fired furnaces or boilers as flame sensors & safety devices
  • Check Valves Guide to check valves and backflow preventers on hydronic (hot water) heating systems (gas or oil fired)
  • Draft Hoods on gas fired heating equipment, function and safety
  • Draft Regulators & barometric dampers on oil fired heating equipment
  • Expansion Tanks Guide to pressure control and expansion tanks on hydronic (hot water) heating systems (gas or oil fired)
  • Fan Limit Switch on hot air furnace heating systems (gas or oil fired)
  • Flue Gas Spill Switch on gas fired heating equipment sense combustion and protect from blocked flues
  • Gas Piping, Valves, Controls including gas regulator assembly and other controls
  • Heat Won't Turn Off - Stop Unwanted Heat explanation of why heat may continue to come out of radiators or baseboards even though you have turned down the thermostat
  • MIXING / ANTI-SCALD VALVES: Guide to mixing valves on hot water heating systems and radiant heat systems
  • Power Switches to turn on or off heaters for furnaces & boilers, oil & gas fired, heat pumps or electric furnaces or boilers
  • RELIEF VALVES - TP VALVES: A guide to temperature and pressure relief valves & safety controls on hot water and steam heating systems
  • Stack Relay Switches Explained on oil fired furnaces or boilers as flame sensors & safety devices
  • Thermostats & Heat Controls for furnaces & boilers, oil & gas fired, heat pumps or electric furnaces or boilers
  • Water Feed Valves: A guide to water-feeding/pressure-reducing valves on hot water and steam heating systems
  • Zone Valves: A guide to zone valves for heating zone control on hot water heating systems

While going through the detailed sequence in the operation of the heating boiler, watch for and inspect the condition of the heating boiler controls and safety devices (as required by ASHI 9.1.A.3 automatic safety controls).

Zone Valves on Indirect-Fired Domestic Hot Water Heaters

Indirect fired hot water heater schematicIndirect fired hot water heaters, in some designs, use a heating coil located in the bottom of the hot water tank to heat the domestic hot water (used for washing and bathing).

A typical design will include a thermostat on the water heater that will cause hot water from a physically separate heating boiler to circulate through the heating coil located in the bottom of the indirect-fired water heater.

A separate loop of piping conducts water from a nearby heating boiler, through the coil in the bottom of the indirect fired water heater tank (thus transferring heat to water in the water heater tank), and back to the heating boiler.

Sketch (left) courtesy of Carson Dunlop.

The water temperature inside the indirect fired water heater tank is sensed by a thermostatic control that causes the hot water tank's contents to be re-heated as needed, typically by turning on a circulator pump that moves hot water from the separate heating boiler through the coil in the bottom of the water heater.

While typical indirect water heaters use a heating loop encompassing a circulator pump and check valve, some systems may use a zone valve in this piping loop that first opens to let hot water flow though the piping loop (boiler to water heater coil and back to boiler), and second, when the valve has opened, it turns on a circulator pump to cause water movement.

This arrangement (or a simple check valve) prevents water in the hot water tank from being heated by the boiler when it is not needed (circulating by convection, for example).

See Indirect-fired Water Heaters for details.

Questions & Answers regarding this article

Questions & answers about zone valves on hot water heating systems: installation, diagnosis, repair advice.

Ask a Question or Search InspectAPedia

HTML Comment Box is loading comments...

Recommend / Share this Article            

...

Technical Reviewers & References

  • InspectAPedia.com® - Daniel Friedman - Publisher & Editor.
  • InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
  • Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
  • Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

  Zone Valves - see detailed links at pageleft

  • Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
  • Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
  • National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
  • The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
  • Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
  • The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
  • Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
  • "Residential Steam Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
  • "Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
  • "Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
  • Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
  • Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
  • Installation Guide for Residential Hydronic Heating Systems
  • Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
  • The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

  • Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
  • Fuel Oil & Oil Heating Magazine, 3621 Hill Rd., Parsippany, NJ 07054, 973-331-9545
  • Goodman Furnace High Temperature Plastic Vent HTPV safety recall US CPSC notice
  • Home Heating System Should Be Checked [for proper venting and for CO Carbon Monoxide Hazards - DJF]
  • Lennox Pulse Furnace Safety Inspection/Warranty Program: Carbon Monoxide Warning
  • ...

Home About Us Accuracy Contact Us Content Use Policy Printing Tips Privacy Website Description © 2012 Copyright InspectAPedia.com