There have been a number of requests through threads, email, and PM for information on the features of the new V3 thermostat firmware. Thought it would be good to make a thread listing them and to answer questions. We'll start with the higher level stuff, and since you all are hounds for details I'll then go into a some more detail in explaining some things and some additional changes. This information covers up to V3-064, which is our currently shipping Coal-trol software.
- TS2ES: This year we have discontinued the TS1 and have introduced the new TS2ES, which preserves the EnergyStar features of the TS1 but puts them in the TS2 package. This was to reduce costs associated with maintaining the TS1 and allow for additional cost savings on the TS2.
- Convection fan on MAX setting: This change will run the convection fan at the speed appropriate for the setting. Older versions had the fan still linked to the non-overridden feedrate and could result in the stove getting excessively hot while making MAX adjustments.
- Convection fan start boost: Whenever the convection fan is turned on it will run at 100% for a few seconds before slowing down to the speed called for by conditions. This overcomes motor "stick" when trying to start at low speeds yet still allows setting as low a minimum running speed as the motor will support (via CFM, in the list below).
- AUXFAN support on TS2: We've turned on the dry contact support on the TS2. Gets rid of a confusing prior requirement that only the TS1 could operate that output on properly equiped control modules.
- Manual convection fan control: The manual fan speed control feature of the TS1 is now in the TS2. Shows "MANFAN" in round robin when it is engaged and slowly flashes the status LED.
- Manual convection fan safety: We've added a safety feature which will automatically return convection fan control back to automatic if the speed is set too slow for too long compared to the feedrate. In this way the control cannot be accidentally left in a state that will allow the stove to overheat. I'll post more about this later.
- RESET: A RESET option was added to advanced menu which will set all the user setting parameters (Programmed setpoint, SETUP and Advanced Menu settings) to factory defaults.
- CFT (Convection Fan Threshold): Located in the SETUP menu, the user can adjust the feedrate at which the convection fan will turn on. In later V2 versions this was included as the "FSET" option.
- CFM (Convection Fan Minimum): Also located in the Adavanced Menu, this allows the user to change the lowest speed the convection fan will be run at.
- Temp BIAS: Located in the Advanced Menu, this setting allows the user to change the calibration of the temperature readings. This was also in later versions of V2.
- SFT (Supplemental Fan Threshold): Located in the Advanced Menu, this can be used to adjust the feedrate at which the Supplemental fan (AUXFAN) output turns on, thus allowing adjustment of which feedrate an attached furance's blower engages. In later versions of V2 this was present and called "SFN".
- Celsius now displays temperatures the nearest .1 degree. More on this below.
- HLF was moved to the advanced menu from the SETUP menu.
- Some ignition timing changes, more below.
While we never had any reports of overheating problems, the number of TS1's sold over the years has been significantly lower than the TS2s. By adding the manual fan speed feature to the TS2 we were concerned that we may start to get reports of people forgetting they set to run at a low manual fan speed while the stove is cranking at a high feedrate. To address this we introduced a safety feature which will return convection fan control to automatic if a the feedrate is above a threshold for more than a threshold number of minutes. These two thresholds are user adjustable in the advanced menu through a feedrate threshold ("MF") and a duration threshold ("MT"). You might ask, "How does that maintain safety? Can't I just set both to maximum and defeat the safety?" The answer is no. The two settings are linked so that there is an upper limit between the two that cannot be exceeded. This limit is based on multiplying the two settings together. The product can not be larger than 3600. For example, the defaults are MT 60 and MF 60 (60x60=3600). This means if the FR is above 60 for 60 minutes it will cause the fan to return to automatic. If you go in and adjust the feedrate threshold, MF, to 70 it will cause the MT setting to be reduced to 51 minutes. In this way there is a maximum energy output that can't exceeded without the control making sure that heat is moved off the stove by the blower. The choice of 3600 being the pivot point was based on the selection of our defaults of 60 and 60. We'll be interested to hear people's experiences with manual fan control and this safety. We believe it is a sound feature and shouldn't interfere with most usages of manual fan control, but are definitely open to feedback so we can make adjustments in future revs if need be.
Ignition Timing Changes
First, the old V2 timings will work for most people. We made some changes because our final element design and power supply selection allowed for more element "on" time and thus the most reliable starts. We have tested with the old timing, though, and it works well. If you run into trouble with it, make sure to call us so we trouble shoot it with you and if necessary get you updated to the newer firmware.
Celsius Temp Displays
There was an issue with Celsius mode where it was possible, due to conversion from Fahrenheit, that button presses would not register a visible change in the Celsius setpoint displays. By extending the display to show tenths this issue is removed. This does not mean that setpoints can be set in increments of .1 C, only that it displays the Fahreheit temperatures to the nearest .1 C. Each button press still moves the underlying setpoint by 1 F and we still operate internally on degrees Fahrenheit.
Convection Fan Theshold and Minimum Speed
These showed up late in the V2 series but didn't get too much exposure. We've reworked them for V3 based on some dealer and customer feedback. They are designed to address a number of issues brought up in the first 2-3 years of sales. First, on some stoves there were reports that the convection blower wouldn't run at minimum speed. It would require FR to get a couple of percent above the threshold before it would reliable start and continue to turn. The CFM setting can be used to address this. The new convection fan start boost feature listed above addresses the starting issue independently of the minimum running speed of the fan. On the other side, there were also reports from people whose motors seemed to turn very freely and had extra turn down potential that they wanted to take advantage of. CFM can be used to address this too. Next, we got reports that some people felt the air being blown out at minimum was too cold. Sometimes this appeared to be a personal preference issue and other times there appeared to be a genuine difference in how hot some people's stove were at low firing temperatures, particularly if they were running very low MIN settings. To address this we added the CFT setting so the user can adjust at which feedrate the blower will start and thus how hot the minimum fan speed's air will be.
Some other things you guys might be interested in:
- New powerup sequence: Firmware version, thermostat model, and OEM strings shown on powerup. Easier to find out what version someone has (both for their own information and if they need to call us for support).
- Test Mode: This is still available on the extended operations menu, but it is now also accessible by pressing and holding the Menu button while the thermostat is powered up. Nice time saver while troubleshooting.
- Convection fan speed logic: Those with V3 and earlier thermostats (and those who follow Coal-trol threads on the forums here) will know that there has been a good deal of confusion over how the convection fan speed and the feedrate are related. In those versions fan speed was based on what is called an exponential lag function. This function has the virtue of being simple and in many cases it can mirror certain natural processes, making it ideal for controls logic. However, in the case of fan speed it seemed to be causing more trouble than it was worth. In this new version we've modified the speed control logic to use a simple to understand and predict linear ramp function. It is set to take 30 minutes to go from stopped to full speed when the FR makes a change from 0 to 99. Said another way, the fastest the fan speed will change is 3.3% each minute. This delay should be better matched to the stoking and heat delivery of the stove and it is easier to understand and explain.
- Fan Speed and Feedrate displays have been moved out of the SETUP menu and into the first positions upon pressing the menu button from the round robin (before the setpoint programming screens). In the first version we had FR in the round robin, in V2 we moved it to the SETUP screen only, and after some pushback we hope placing it in this easy to reach place (but without it cluttering the round robbin) is a desirable balance.
- Hold and Override display changes: Our old indicators for these modes were kind of confusing. V3 changes to standard indications. Temperature hold mode shows an "H" in the current setpoint display of the round robin and slowly flashes LED. Temporary override shows an "O" in the current setpoint display of the round robin.