Spud Spikes for baking, grilling, and barbequing.

Unit may need to have some adjustment

QuestionI'm pretty sure that modern electronic thermostat control units do not have the heat anticipator that the older dial units have. The modern electronic units attempt to achieve the same result by using hard-coded software programming that is not adjustable.

The performance of my Honeywell digital unit (T8624D) is less than stellar with my gas furnace. It constantly cycles up and down, and I am actually considering returning to the old dial-type unit. Any advice?

AnswerThermostats all contain some form of an anticipator, with the exception of the newer solid state models. Rather than an adjustable heat anticipator, they have a factory setting for either a fuel-fired or an electric resistance heat furnace. The fuel-fired unit setting allows the burner to fire for a set time before the fan comes on. The electric resistance heat unit has the fan come on at the same time the heating elements are energized. The thermostat also has a factory setting for the number of times it will come on in an hour. This setting can be changed by the installer.

Because I don't have the rest of the numbers that follow the product number T8625D, I can only make generic suggestions for you to check out. It's possible that the cycle rate needs adjusting. Cycle rate adjustment screws allow you to customize the thermostat cycling performance to various types of heating equipment for optimum room temperature control. Most applications will not require a change in cycle rate.

The room air temperature will normally vary slightly from the comfort temperature setting with the cycling of the furnace or air conditioner (if you have one). Adjust the heating cycle rate by turning one (or both) cycle rate adjustment screws on the back of the thermostat. Either back out the screws about one-half to one complete turn, or turn them in until tight. Study the diagram in the installation manual that came with your thermostat, or go online to www.honeywell.com to find the manual. You can also contact Honeywell directly at 800-328-5111; their customer service reps are pretty savvy trouble-shooters.

I've been told that this particular thermostat will cycle on and off until it reaches the thermostat setting. It's not uncommon for it to cycle six or more times in an hour.

There is also the possibility there's something wrong with the thermostat or that this is not the best thermostat for your application. You may want to bring in a heating contactor to address the problem.

Copyright © 2005, 2006, & 2007 LAF/C.R.S., Inc. All rights reserved.
Question answered by Leon A. Frechette.

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