I ran my furnaces several times this cold spring and noticed the original thermostats are almost useless. Their hysteresis is so bad the furnace runs on and the temp will vary 10 degrees or more.

They couldn't use the typical mercury tilt switch since the coach isn't always level. The bimetal coil and magnetic contacts are very crude and so is their function.

Since these are generic 2 wire systems, I replaced them with a standard household Honeywell solid state type. What a difference! Temperature is regulated very closely and the furnace runs shorter cycles. They don't care if they are level, they display current temp and time, and can be easily installed.

I got my thermostats for under $20 each. If you live where you need heat, consider this simple upgrade.

Mine was the same way, so I adjusted the anticipation slider until it worked the way I wanted. Took a couple of tries to get it where I wanted.

Since household 'stats are designed to work on AC, it's important to make sure what is chosen is compatible with DC.

Most of the thermostats don't care anymore about AC or DC, they have internal batteries and an internal relay single pole switch to make or break.
My Hydroflames did not have any anticipator, real cheap models.
The new ones can be set for cycle times, etc. and are pretty cheap.

I checked the rating on the thermostat relay. They are rated for 1A at 24 volts. You can use them for any low voltage, low current application.
They would not work for 110 AC like baseboard heaters or heat pumps without an additional power relay.

Good idea to replace! When you get a chance, please post the model number.

Here are some pics of the upgrade.
Old thermostat:


With the cover off, you can see how simple it is. The recess at about 2-4 o'clock on the spring coil is where the slider for the anticipator would be. As you can see, there isn't one. A very crude device.


The new baseplate attaches easily, 2 wires and the connections are labelled with the wire color.



Final view: Time/temp display and backlighting, too.



The thermostat is a Honeywell model RTH2300. They come in several versions depending on the programming options (weekly, 5/2 daily setbacks, etc)
I don't need the programming functions, I just set the "hold" temp. They generally run about $25 at Home Depot but since the 5/2 one was on sale for $19 I bought those. They will hold the temp +-1 degree. Way better!

One caveat: As you can see from the label, the contacts in the thermostat are rated for only 1 amp. Some furnaces use the thermostat to switch power on and off for the ignitor circuit board, the gas valve, and the blower fan. Combined, they require more than 1 amp. If that is the case a small relay can be installed in the furnace to switch the power and the thermostat only switches the relay coil.