# What does this dial inside my thermostat do?



## saladdin

I have a cab50 with the standard thermostat that comes with it.

What does this dial under the cover control?


It reads "Longer Cycle" with numbers showing:

.2
.15
1.2
.8
.6
.4
.3
.25

The dial is set between .6 and .4


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## Pyro101

That dial is the heat anticipator. What it does is it makes the thermostat stop calling for heat before the room gets too warm. It prevents heating overshoot. When the heat is on the stove is hot therefore when the thermostat stops calling for heat the stove still has to cool down and expel the heat into the room. That dial adjusts when the thermostat senses the room is at temperature before it's actually at temperature. This dial is on most any generic thermostats.


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## saladdin

Pyro101 said:


> That dial is the heat anticipator. What it does is it makes the thermostat stop calling for heat before the room gets too warm. It prevents heating overshoot. When the heat is on the stove is hot therefore when the thermostat stops calling for heat the stove still has to cool down and expel the heat into the room. That dial adjusts when the thermostat senses the room is at temperature before it's actually at temperature. This dial is on most any generic thermostats.


So the thermostat has a thermostat.

Thanks for the lesson.


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## DexterDay

Is that the "Swing"? If so, I would raise it. If its adjustable by the end user?

I prefer 2° each way. Example : If set at 70°, then stove will kick on at 68° and will run till it gets to 72°… This prevents short cycles on a Quad/Heatilator. Which can overfire the unit.


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## Pyro101

No it is not a "throttling range" adjustment. It is only used for the heat mode. When the thermostat calls for heat the "heat source" (gas furnace electric furnace pellet stove whatever is providing the heat to the space) comes on gets hot and puts heat into the space. As the space heats up the thermostat has to know when to shut the heat source off before the room gets to the set temperature because the heat source has to cool down before it can shut off.
Simply stated, if the set point for heat is 68° the thermostat will most likely call for heat at 67°. When the furnace or heat source comes on and heats, the thermostat needs to shut the furnace or heat source off at 67.5 or 67.8 depending on how long the cooldown process takes for the heat source.
Therefore the thermostat has to "anticipate" when the space temperature is going to reach the desired set point.
That is what this adjustment is for. A rule of thumb is that a small space needs a higher heat anticipation set point because it will warm up very quickly. A larger space needs a lower heat anticipation set point because it will warm up slower.
I hope this helps and makes sense.


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## Pyro101

saladdin said:


> So the thermostat has a thermostat.
> 
> Thanks for the lesson.



Yes precisely, the thermostat has a thermostat. 
It is basically a little built-in heater that actually fakes the thermostat out and makes it think the space is warmer than it actually is. This allows the thermostat to stop calling for heat before reaching the desired setpoint and allowing the heat source to cool down right before reaching the set point. As it cools down heat will still be expelled into the space therefore cycling the heat source off at your desired set point.


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## saladdin

Pyro101 said:


> Yes precisely, the thermostat has a thermostat.
> It is basically a little built-in heater that actually fakes the thermostat out and makes it think the space is warmer than it actually is. This allows the thermostat to stop calling for heat before reaching the desired setpoint and allowing the heat source to cool down right before reaching the set point. As it cools down heat will still be expelled into the space therefore cycling the heat source off at your desired set point.


 
I was hoping it was a "swing" adjuster. But now I know. Thanks so much for taking the time and explaining it.


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## tlc1976

I just found this thread but thanks.  I had been wondering just how the heat anticipator was supposed to work.  I didn't think of it being a heater to fake out the thermostat, but I knew it was a resistance wire.  So with the on/off thermostat I made, I just bypassed the anticipator altogether because I didn't want it dropping voltage to the relay.

It is not the full swing but it does affect the swing.  If you bypass it, or at least put it to its lowest setting, it will make the appliance run longer per cycle which is often better for a stove.  Turning it up will only cut the cycles shorter.


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## saladdin

tlc1976 said:


> I just found this thread but thanks. I had been wondering just how the heat anticipator was supposed to work. I didn't think of it being a heater to fake out the thermostat, but I knew it was a resistance wire. So with the on/off thermostat I made, I just bypassed the anticipator altogether because I didn't want it dropping voltage to the relay.
> 
> It is not the full swing but it does affect the swing. If you bypass it, or at least put it to its lowest setting, it will make the appliance run longer per cycle which is often better for a stove. Turning it up will only cut the cycles shorter.


 
I got tired of it so went to the lux in my signature. Much better set up with the programmable option.


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## tjnamtiw

My stove manuals tell you to turn that anticipator down to the lowest number to prevent short cycling.  I believe it would function as a crude type of 'swing' adjuster although it would be trial and error to find the correct adjustment point and it might be affected by ambient temperature variations.


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## SmokeyTheBear

tjnamtiw said:


> My stove manuals tell you to turn that anticipator down to the lowest number to prevent short cycling. I believe it would function as a crude type of 'swing' adjuster although it would be trial and error to find the correct adjustment point and it might be affected by ambient temperature variations.


 
Yep that would cause the largest overshoot allowing the longest time for the stove to cool below the magic damn the torpedoes full feed ahead on startup.


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## PoolGuyinCT

What is the out of box factory setting for it?


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