Home Heating System Control Question

There is probably a thread in this titled, "the first time I wore my new hearing aids".

I discovered all manner of unfamiliar sounds when I got mine.

No clue about your real problem.

8099 - The RiteTemp Support Site - 8099 Technical Support ...

Yes, I can hear a lot of things now that I have not heard for many years. Some that I rather not hear like my wife asking me to do something that I don't want to do

Make sure to install a switch, then.

on her or the thermostat?

Actually, in all seriousness, the control system is faulty. Replace the thermostat. There is supposed to be built-in time delay to the controller, although, some older systems may have had an external (to the thermostat) time delay relay that could fail.

You can DIY and see if problem is solved, or you can call a reputable service technician to correct the problem.

It would be hard to describe all possible variations, but a time-proportioned loop that also includes any start/stop delays can get out of hand pretty easily. Sometimes a simple on/off thermostat is best, as long as the deadband is not so tight as to promote short-cycling.

The thermostat has no means for adjusting the dead band. I checked on the manufacture's web site ,but found no other user instructions other then the wiring diagram. The thermostat has a jumper pair, one for electric and the other for gas. It is set for gas.

Hmm, that's intriguing. Maybe a possible difference would be that electric is assumed to have instant control, but gas has some delay such as for flame verification. (I'm speculating here, just based on general ideas but no familiarity with your system details.)

Short cycling can be caused by several things....the most common is having a vent pushing air directly at the T-stat....probably the second is the T-stat itself either having the differential set at 1° when it should be at min 3°, or malfunctioning, worn out or defective....Depending on the type of furnace it could be the fan control....In any case you're going to need a pro to check it out...

I'd be tempted to replace the thermostat with a programmable unit. Decent ones are about $100 at the big box stores. Sounds like the thermostat may be defective. I have a similar forced air system with gas heat and an outside condensor/compressor and an A-coil in the air handler for A/C. I have my deadband set for one degree and mine will run about 20 minutes in winter then shut down for at least that long, even when it's stinking cold outside. I have a 2400 sq ft house with lousy insulation (bit by bit, we're fixing that) and a GE 80,000 BTU/hr furnace circa 1973.

You might check to see if it is properly wired...

http://www.ritetemp-thermostats.com/80XX/images/8099_installation_guide.pdf

From http://www.ritetemp-thermostats.com/faq_general.pdf

"Is there someone I can contact if I have a question about the installation or operation of my RiteTemp thermostat?

Yes, RiteTemp offers a US‐based technical support staff to help you with any questions you may have. Technical assistance is available over the phone at 877‐505‐2353 or Via Email at support@ritetemp‐ thermostats.com"

No that's not normal for any type of standard gas furnace control system. It's hard on the gas valve and wastes a lot of fuel that goes up the stack unburned.

As other said there should be a 1 - 3 degree dead band and typical run time of around 15 - 20 minutes if not more between cycles.

Also, please note that the original installer of the furnace and/or thermostat may not have wired the thermostat in accordance with the standard color codes. In my case, my BLUE wire has the 24 VAC on it, not the RED wire which would usually be connected to RC and RH (with a jumper between them). I had to go down to the furnace/air handler and tear it all open to determine which wire went where. On the thermostat RC means Red-Heat and RH means Red-Cooling.

If you Google "thermostat wiring colors" you will get a headache-inducing number of variations.

I have a Temp-Rite Model 8030 programmable unit. I've had it for about 14 years and once I figured out the wiring, it's worked great.

This is about the best picture I have been able to find yet that clearly shows how everything is connected together. Everything that is to the left of the five colored dots is what is 'inside' the thermostat. Sometimes you just have to use trial and error.

Good luck with your quest.

Something's not fully right there; there is a short circuit on the 24V side, namely the bottom wire through the blue dot.

Quite right...here is a correct schematic...bear in mind some t-stat's have a jumper wire for gas heat, as the fan is controlled by the fan limit control in the furnace(delayed) rather than the fan relay as it would be for electric resistance heat...

There still may be some missing wiring connections in this diagram. When the FAN switch is open there is no other path shown to energize the fan.

In the sytems I have repaired in the heating mode the fan is energized by a thermostat switch in the plenum when the temperature rises to some set point. This prevents circulating cool air. While in the cooling mode the fan start when the cooling set point is reached on the home thermostat.

Solar Eagle After I reviewed the diagram again and read the text above it and realized you had covered the comments I made above.

Yeah, I saw that too but decided that since that was 'inside' the thermostat, I would just ignore the drawing error. It just gives the reader an idea of what's happening.

A conventional thermostat (circia 1950's etc.) has an adjustable anticipator. The anticipator should be adjusted to match the gas valve current .. or electric heating contact current.

If your gas furnace is shot cycling, it's anticipator is either not adjusted, or it's solid state version of anticipating is not function properly. Swap it out with a conventional thermostate ... and it should work properly if this was the cause of the problem.

I suspect the heating resistor in the thermostat isn't doing its job, Mildred. A bit of 'derivative' goes a long way towards stabilising a thermostat.Get your smouldering iron out, and check there are no dry joints first. If that doesn't work then change the resistor. If that doesn't work, change the whole thermostat.

Just a followup:

I replaced the thermostat, which was 30 years old, with a new programmable one ($18.00 and 15 minutes to replace), and the heating function is working correctly now. I haven't tried the cooling yet as it is still to cold outside. Fortunately, whoever installed the original thermostat labeled the wires, so the hook up was a piece of cake.

Thank you all for your prompt and helpful advice.