Thermostat Span Setting Question

[Dave Gallant]

Hello:

My digital thermostat [for hot water baseboard system] allows for three 'span' settings. The factory set one allows for a one degree span - i.e., if I set it at 72 degrees, the system calls for heat at

71 and goes off at 73. This particular unit has an adjustable span setting, one is higher and one is lower.

Question - other than a matter of one's comfort, is there any financial/efficiency benefit to setting the span either longer or shorter than this one degree setting?

Thanks,

Dave

[TURTLE]

This is Turtle.

Now unless you have a non standard thermostat used here. The spands are set this away.

1 degree differencial [ heating mode ] say set at 70ºF will get you to turn on at 69ºf to 69.1ºF and cut off at 70ºf to 70.5ºf.

2 Degree differencial [ heat mode ] say set at 70ºF will get you to turn on at 68ºf to 68.1ºF and cut off at 70ºF to 70.5ºF.

3 degree Differencial [ Heat mode ] say set at 70ºf will get you to turn on at 67ºF to 67.1ºF and cut off at 70ºf to 70.5ºF.

You had said it goes 1 degree over the set point to turn off. I'm not versed on hot water base board heaters but your over shooting by 1 degree tell me you don't have the fuel type set right, antisipator set right for base boards, or you have the wrong thermostat for base board heaters. i can be wrong on base boards being able to over shoot and be alright but most every other type thermostats for heating will have antisipators to stop this over shooting of the temperature.

Most all Honeywell and White Rogers digital thermostat will have the button to set the fuel type and a botton for the [T.D.] temperature differencial you want.

Now you setting for a 3 or a 1 degree temperature differencial would not be really any good fuel savings but the 3 degree differencial might be a little better on fuel on a base board system if this setting would not be a problem for you in anyway.

TURTLE