A closer look: Inspect your thermostat before problems arise

By Rob Parker, Special to Postmedia Network

With winter on our doorstep, now’s the time to make sure your thermostat is working properly to avoid issues when you need it.

Thermostats are used to ensure the comfort of building occupants through the proper control of heating and cooling cycles. Home inspectors are not required to inspect the calibration of thermostats, but they should be able to provide you with solutions to some of the common problems experienced by homeowners.

  • Erratic operation or fluctuating temperature: This is often caused by poor pin connections between the thermostat and the backplate when the backplate is flexed against an uneven wall. To allow the backplate to flatten out, loosen the screws that attach the backplate to the wall, then snap the thermostat back onto the backplate.

  • False or “ghost” readings: If the thermostat is installed in a location where it incorrectly reads the room temperature, it will cause unnecessary furnace or air-conditioner cycling. Locations that may cause the thermostat to give false readings include near a heat source, such as a fireplace, hot water pipes, bright lights, direct sunlight or electrical appliances that produce heat; in a drafty hallway, or near a window or exterior door that is opened often; and on an outside wall. Outside walls can be affected by outside temperatures that may make the thermostat “think” the air in the house is warmer or cooler than it really is.

  • Thermostat doesn’t respond to changes in room temperature: This can happen when there is air passing over the temperature sensor from a hole in the wall behind the thermostat, through which wires enter from the air-handling unit. To rectify this, insulate the hole behind the thermostat with insulation, spray foam or any other insulating material.

  • Inaccurate temperature: A convenient way to test the temperature sensor is to tape a thermometer to the wall next to the thermostat and wait 15 minutes. A faulty thermostat should be replaced.

  • Loss of power: If the air handler powers the thermostat, check the circuit breaker for the air handler and make sure it has not tripped. If the thermostat is powered by batteries, check if they need to be replaced. You should replace the batteries at least once a year, preferably twice, spring and fall.

Most thermostats contain two meters — the “set” temperature that the thermostat is asking for and the actual temperature. On a traditional dial-type thermostat, the user can increase or decrease the set temperature by rotating the dial. Thermostats can be manually controlled or set to activate automatically based on timers or room temperature readings.

Newer thermostats have digital displays that can be used to adjust for automated heating and cooling schedules.

Many people believe that furnaces work harder than normal to warm an area back up to a comfortable temperature, which will counteract energy savings gained from turning the thermostat down. This belief is a misconception that has been disproved by years of studies and research. Fuel is saved between the time the temperature is stabilized at the lower level and the next time heat is needed, while the fuel required to reheat the space is roughly equal to the fuel saved while the building drops to a lower temperature. Generally, a drop of two degrees Celsius (3.6 F) will lead to some savings and little risk. Some householders reduce temperatures four to six degrees Celsius (7 – 11 F), but temperature differences this large may create potential comfort and moisture problems.

Maintenance tips

  • Make sure your thermostat is set to the proper position for the season: cooling or heating. The air conditioner will not run with the switch set to heating and, conversely, the heating system won’t run if the thermostat has been set to cooling.

  • Turn off breaker for air conditioner or pull fuse to prevent accidental operation of air conditioner.

  • Give the thermostat’s interior a light dusting with a small soft paintbrush. Canned air can also be used to blow off dust. Twist the screws to remove the cover. Be sure to clean the contacts, which are small metal plates within the unit. The wires coming from the transformer attach to the contacts. Do not touch any of the interior parts with fingers.

  • Thermostats that contain a mercury switch must remain perfectly level or they may not control the temperature setting. To check, simply place a small level on top of the thermostat and adjust the screws that hold the thermostat on the wall.

Rob Parker is a registered home inspector (RHI) with the Ontario Association of Home Inspectors, and an ASHI certified inspector (ACI) with the American Society of Home Inspectors . Rob can be reached at Thamespec Home Inspection Service (519) 857-7101, by email at thamespec@rogers.com or visitwww.thamespec-inspections.com 

Date : 10/29/2015