concept of the thermostat

[vinnnie]

My dad has a vacant apartment and does not want the pipes to freeze in the boston winter.Does anyone know at what temperature outside the house has to be for the pipes on the inside of a house to freeze, we have the old forced water radiators.
My dad's buddie put in a digital thermostat in place of the old round one; this is my challange. I set it to 50 degrees and the temperature will come down to like 60 and jump up by itself to 70 (why does it not go down to 50?)(and why does it jump up by itself?) everytime why does it not come down to 50? or am I missing the concept of thermostat theory.
thats why I'd rather just turn it off; and find out what temperature to turn back on so the pipes don't risk freezing. thankyou

[SSN596]

You are not missing the concept. But, the thermostat you have is simply not designed to do exactly what you want. It may have the bottom end labeled "50º" but in reality, its usable, reliable range probably stops about 60, and its swing is quite large.


There are thermostats made to allow a temp setting down at 50 or below. Check out Honewell , Robertshaw, and White Rodgers websites.

If the outside temp gets down to 30º, then EVENTUALLY, the inside temp would also get down to 30º and the pipes would freeze. As a practical matter, rather than try to calculate all this, just get a thermostat to keep the inside warmed up to 45 or more. Now, if you have pipes in an uninsulated outside wall, or unheated attic, this is a different problem altogether.


Let us know how it works out.

Jim........(native of Newbury....now Calif)

[vinnnie]

thanks and why

Thanks jIm, do you have any clue why the temputure would go up by itself after setting it to 50 then it goes up to 70 thankyou sir

[LazyPup]

If its a digital thermostat and its changing by itself it probably has an automatic day stat / nite stat feature,,you would have to either turn the setback off or set both daystat and nitestat at the same desired temp.

[SSN596]

The WhiteRodgers 1E30-373 has a set-point range of 40 to 75. This should work for you.

[Phelps]

Thanks jIm, do you have any clue why the temputure would go up by itself after setting it to 50 then it goes up to 70 thankyou sir

I had the same thing happen this winter with a Robertshaw "Chase" programable, and it was trying to cycle on when it was 5 degrees ABOVE set point. Then it would high limit. The pipes froze in the trailer. I got er going again and set the programable to "manual" and it did it again anyway! Luckily I only had one solder joint come apart in a wall I could easily open and got it fixed. (Whew). I put the Honeywell round thermostat in, so I could set it back to 45 degrees while vacant and haven't had a lick of trouble since. I guess from all that I am reading that these programables are finicky at these low set points (around 50 degrees). Not worth risking and having pipes rupture on you.

[SSN596]

Ah, the venerable Honeywell T-87 round thermostat! ALAS, it has been terminaed by Arnold here in California. NO mercury thermostats allowed as of Jan 1, 2006. Look for the mercury ban to be coming soon to a state near you!