Guide to Diagnosing Uneven Heat in Rooms Served by Radiators, Baseboards & Convectors
UNEVEN HEAT DIAGNOSIS - CONTENTS: Explanations for Uneven Heat - Mixed Systems of Radiators & Baseboard Heat - Why do different radiators or baseboards heat unevenly in a building?Things to Check if Heat in the Building is Uneven or Incomplete with Some Areas Receiving little or no heat
Explanations for Uneven Heat - Mixed Systems of Radiators & Baseboard Heat
Mixed hot water & steam combinastion heating systems
As Carson Dunlop's sketch (left) shows, a mixed heating distribution system that combines cast iron radiators (or wall convector units) with heating baseboard in the same heat distribution piping loop can produce uneven performance.
The heating system's behavior will also be affected by the location of the thermostat. In our sketch, the heating control thermostat is located near the radiator.
Because cast iron radiators take longer to get hot in response to circulating hot water in the system than does finned-tubing baseboard, the room where the baseboard heat is installed will be very hot, maybe too hot, early in the heating cycle (while the radiator is heating up).
Then as the thermostat (located near the radiator) is satisfied and stops the boiler or circulator pump from sending hot water through the heat distribution piping, the hot, high-thermal mass cast iron radiator will continue to warm the room where it is located, while the room with the finned-tubing baseboard will cool off more rapidly.
The result may be that the room heated by the finned-tubing baseboard will be sometimes "too hot" and other times "too cold".
List of Things to Check if Heat in the Building is Uneven or Incomplete with Some Areas Receiving little or no heat
Watch out If part of a building is getting heat and part is not, and the problem is not the radiator or baseboard itself, check these possible causes of uneven or partial heat distribution:
Check for additional thermostats controlling different building areas and be sure the thermostat in the cold area is calling for heat and Check for an inoperative room thermostat in some areas (if more than one thermostat is in use in the building)
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(Jan 24, 2012) scott said:
i can't help but comment after reading the article but in most cases the boiler is not able to produce enough heat in the beginning or during the heating cycle to cause the baseboard to give sufficient heat. baseboard needs a good 180 deg. to heat and as we know standing cast iron will give heat at any temperature. most (converted)gravity systems run much cooler (if they don't then you are really throwing a lot of money away and you have a lot more problems than this one)
Question: better heat control
(Apr 3, 2012) Jessie. said:
I have cast iron baseboards on my entire circut. I also have programable thermostats. The issue I have is at night... i have it set at 60... Why so low? because when the heat kicks on it runs and runs untill the air heats enough to trigger my thermostat to shut off. then for the next 30 min or so the room continues to heat... sometimes up to 70 degrees. I spend my whole night freezing and roasting. I need to configure a control system to kick on the heat for 5-10 min to heat up the baseboard and then let the carry over heat bring the room to a more even temp... I have looked for time stats but none of them will have it cycle on and off. I have looked at remote sensors... I think this may be my only option... any advice? I will save loads of fuel too since I won't be heating beyond my needs any more.
I would look first at the properties of the building: look for air leaks, drafts, significant heat loss points
Second look at the thermostat location: it may be in a bad spot that doesn't accurately reflect the room temperature or that is affected by outside conditions, drafts in walls, even heat from the other side of a wall.
Question: insufficient heat in some rooms
(Jan 27, 2013) ralph said:
we have traditional radiators in the old part of our house and cast iron baseboards in our bedroom, which is an addition from before we bought the house 25 years ago. We get very even heat from the traditional radiators but insufficient heat in our bedroom. Don't know if it's simply a difference between the two types of heating or because the bedroom is farther from the boiler than any other room in the house. If I reduce the heat for the traditional radiators, but without changing the temp on the thermostat, will that allow more hot water to reach the bedroom? Any suggestions would be appreciated. Thank you.
Look first for air-bound or partly air-bound heaters in the bedroom or piping to it.
Search InspectApedia for "air bound heating systems" to see details.
THen try drawing a sketch of the heating loop piping so that we can see where the cold bedroom is; let's see if the problem is a remote end of the heating loop bedroom;
Question: heating baseboard wont' shut off regardless of thermostat setting
(Apr 12, 2014) Wayne said:
My baseboard heating will not shut off regardless of the thermostat setting. My house is constantly 81 degrees. There is a switch on the side of my boiler that doesnt appear to be in the in the boiler manual.I tried flipping the switch, the boiler shut off. I dont know if it shut off because the switch controls boiler power or because the baseboard heating is shutting off and the boiler doesnt need to be on. I have a Weil McLain EG-50 boiler i believe, im not sure what the make of the baseboard heating is though. Please help!
Wayne when heat won't shut off I check first for shorted thermostat wires. Try disconnecting the thermostat wires at the control end at the boiler.
Questions & answers or comments about how to diagnose and fix uneven heat problems in buildings with hot water heat.
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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 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
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
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TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
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