We have a newmac wood furnace with a honey well fan limit control. It cuts in but will not cut out.

Once combustion has stabilized any increase in fire box temperature requires an increase in combustion air.

from the manual...
"When burning with wood, the minimum setting for the manual draft slide should be in the centre. (This is the slide knob beside the combustion fan above the firedoor). The closed position is for when burning with oil for a prolonged period (to obtain maximum efficiency) and the open setting is for initially starting a wood fire."

If you're already at maximum draft, you could try burning higher quality combustible material (dryer or higher density wood), increase draft pressure (taller chimney), or larger fire box (bigger stove).

Janet, the problem most likely is not in the thermostat. It is probably the fan relay on the circuit board in the furnace. Some furnaces have an individual fan control board, some furnaces have all the controls integrated within one control board. If your furnace is 20 years old or older, it could be the fan/limit control because at that time all furnaces did not come with a control board. If it is much older than 20 years, it is much more likely a stuck fan/limit.

Yes, you most certainly can. It depends on how handy you are and to what extent you are willing to go to make this happen. A lot will depend on how comfortable you are with electrical wiring and understanding HVAC controls and their function.

First though, this is the typical way a wood fired forced air furnace is designed to operate. There is a control transformer and relay to control either a combustion air fan (that you do not have) OR a motorized damper for combustion air that you also do not have. The relay closes on a call for heat from the thermostat and opens the damper from its minimum position to allow combustion air into the firebox. As long as there is solid fuels (wood) in the heat chamber, the fresh supply of combustion air will allow the fire to burn or begin to burn very quickly.

As the temperature in the wood furnace plenum increases, the automatic fan control will start the fan and it will run as long as the bonnet temperature is higher than the fan'on' setpoint on the fan control... Now the house warms up and the thermostat satisfies which allows the combustion air damper to spring back to the minimum position, causing the hot fire to die down due to lack of combustion air.

The now smoldering fire will not generate enough heat to keep the fan running too long, so the automatic fan control shuts the fan off until the house cools approximately 2 degrees below thermostat setpoint. The thermostat calls for heat and opens the damper and on goes the cycle....

An important item to remember is that on the automatic fan control, there is a 'limit switch' function. The motorized combustion air damper or the combustion air fan must be wired through the limit switch in case the bonnet temperature exceeds 200 degrees F. This function will then allow the damper to go to the minimum position or the combustion air fan to go off, causing the fire to cool down due to lack of adequate combustion air.

You don't want the thermostat controlling the circulating fan directly, because of two things: 1). If the fire is out, there is no heat to circulate but the thermostat wouldn't know that and it would start and run the fan continuously until a fire is built. and ....
2). You would still be running up and down the stairs monitoring the fires burn rate by opening and closing the lower door manually.

ALL the components you need are readily available from WW Grainger....basically : a fan/limit control
a thermostat
a 110v x 24v 40 va control transformer
a 24v spdt relay
20 ga. two conductor thermostat wire
24v actuator and linkages to mount to the existing combustion air damper. A bit of creativity is required here. I would not recommend retro-fitting a combustion air fan.
14-2 wg romex for wiring the fan control

Again, it depends to what extent you are willing to go to achieve the end result. Will it be exactly like a new system?? No, but it will operate a lot better than that which you describe.

sounds like the motor has overheated and/or seized up from the overheating or age. see about getting it rebuilt or replaced

Oil burner trouble shooting and tuning is a little complicated and requires special equipment and know how to get it right. Best to call a tech. for this. The oil suppliers normally have people who have good training and experience.

Probably a bad fan/limit. The way it works is the heat comes on first then as the air gets warmer the bi-metal twist around on the fan limit and at around 110f the fan kicks in. If the fan don't kick on then the limit kills the heat so the furnace don't get too hot.
Newer furnaces use a computer board to drive the fan with a timing sequence.

Of course it could be something very simple such as a contaminated flame sensor. If your furnace if one of them fancy new fangled machines which use a draft inducer fan the control may not be sensing ignition and auto cycling on and off. if that is the case get a dry brillo pad and remove the sensor. Give it a good clean and re install it then retry:
Furnace Lockout


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On the side of the heat exchanger is a fan Klixon that turns that motor on when the temp exceed 110f on the side of the heater. maybe that thang is going out or your fan motor needs oiling and is cutting out on overload. Next to the fan klixon is usually a limit. Both look the same. The fan klixon will have a marking stamped into the metal such as F-120 the limit will have L-240.

If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61

hot air is lighter and requires less cfms to move it compared to your cooling air. It should be set to low or med low speed depending on how far you have to move the air

Yes. If the high limit is tripped, the furnace will bring on the fan continuously until the limit resets. Often, they will not reset if tripped repeatedly. If the furnace is too large for your application, you probably are not able to move enough air to keep the heat exchanger cool enough.

Looks like your fan limit switch may be bad. It fits into the warm air side of the furnace. It tells the fan to come one and off when the heat is blowing over the limit switch. Now if that limit is defective it also will affect the lighting of your heater being it electronic ig-niter or just common thermocouple type controlled pilot light. Now above your post I think the wong information was given about your gas heater, so giving you the exact information will be difficult. Now from hearing you explanation of the problems, I hope my information was a help to you, Thanks Sea Breeze