Thermostat, leave it at one temp. or program several temps.

Hi,

Finally have my EFM coal stoker hooked up correctly ( both inlets used and a bypass installed.) My next question : Is it better to leave thermostats at one temperature constant. or does it matter if we use a programmable thermostat? We have only 2 zones. I was wondering if furnace would work less trying to maintain one constant temp. ( like 70 degrees) versus varied temps. from a programmable thermostat. ( seems like water in radiators cool off too much and furnace has to heat colder water). Any school of thought on constant versus variable temps. for coal usage or would it be about the same?

I am no expert, but I would think it would depend on the btu output of the stoker compared to the btu needs of the house. If the stoker is rated much greater it should bring up temps quicker. If the output and use are the same on a cold day it would run all day to maintain the temp. I like my simple thermostat, turn it down at night and up in the morning. Less to complicate things. Hopefully you have a timer to keep the fire going, I run 1 minute once an hour. If you throttle her back to hard your fire could go out without the timer. The stoker would be like a truck going to West Virginia, coast down the hill when the thermostat is turned down and working hard to make it up the hill. I would think you still would save coal by turning down the heat. MY $.02

bighouse wrote:Hi,

Finally have my EFM coal stoker hooked up correctly ( both inlets used and a bypass installed.) My next question : Is it better to leave thermostats at one temperature constant. or does it matter if we use a programmable thermostat? We have only 2 zones. I was wondering if furnace would work less trying to maintain one constant temp. ( like 70 degrees) versus varied temps. from a programmable thermostat. ( seems like water in radiators cool off too much and furnace has to heat colder water). Any school of thought on constant versus variable temps. for coal usage or would it be about the same?

Fantastic question, I don't know the answer but I've been running my EFM 520 with programmables on two zones and I do notice it takes longer for the heat to reach temp verses oil.

For our situation, we tend to like it cooler when sleeping and when the house is not occupied during working hours, so we have it lower. Unfortunately the 1st floor bedrooms are on the same loop as the rest of the main house, the 2nd floor bedrooms are on a separate loop. If the house was occupied most of the time, then I would probably leave it at one temp., then lower for sleeping hours only.

If outside temp has been constant, I do notice that we use less coal when keeping the house much cooler in our situation. This week is a good example for keeping the house at a constant temp, because of work & school vacations I'm not seeing a huge increase in ash content. Mind you if we are in a cold snap and of course my windows are over 30 years old, I think I wouldn't be able to say that....programmable is the way to go in my situation.

P.S. Do you have your bypass valves "dialed-in"? I'm still not sure what would be ideal for my setup.

Normy

Just my 2 cents ......

Going by the different characteristics of burning between gas, oil & coal, I think those programmable T-stats were made with a gas or oil system in mind. With coal, I'd just leave it at a temp that's comfortable.

Coal can't bang on, bang off like oil or gas.

With the way my system is setup up it makes more sense to keep the thermostat set at one temperature and leave it there. If i turn it down a few degrees overnight i will spend the next morning and afternoon playing catchup. But i have lots of hot water to heat up in my system and a drafty house. My rads cool down way to much with a thermostat setback. If your boiler can heat the water in your system very quickly then turning it back shouldn't be a big deal. But if it takes forever like at my house then just "set it and forget it"

Thats my opinion ...

I don't know either. The rule of thumb in the industry is a 5 degree setback in this area.

With temps in the 20s, and a setback of 5 degrees, our stoker runs from 8-12 hours straight, just to catch up again. I still think we are saving some money though. One thing I noticed is that 60 degrees in the warehouse is much easier to attain than 65. That extra 5 degrees takes several more hours of stoking to attain.

It all depends on if your system is balanced to recover from set back or maintain a comfort goal! I do both.

Thank you all for great feedback. Many different opinions. I guess thats why it pays to experiment with each system. There is satisfaction trying to get system "just right'. I am going to set thermostat at one temp. and see how that goes compared to different programs, like I have now. Again, thank you all for your help.