Help with devising an overide T-stat

Paul_35

I have a 5-zone forced hot water heating system controlled by Aube t-stats. I am trying to find a manufacturer of a 12v DC timer that I can program over a 24 hour period to run for a set amount of minutes for each period.

The need for this is two of the zones are heated by a woodstove during the waking hours, so that these zone's rads go cold during that time making start-up in the wee hours costly [and also making the supply lines cold and lonely throughout the day on the sub-freezing days of deep winter].

Any ideas on where to locate a programmable, low-voltage timer would be greatly appreciated.
/Paul

Duncan_2

12 vdc timer

Try a net search using "12 volt DC interval timer" or some such.

In about ten seconds, I found:

http://www.backwoodssolar.com/Catalogpages2/wiring2.htm

Plumbob

You could also use a 120vac timer (like the ones used to control appliances) and connect it in parallel to the circulator pump if you are comfortable doing 120vac wiring. Some of them will do many cycles each day.

Incidentally, it may be costly to heat up something that has been cold for a while, but it is even costlier to keep it warm when it does not have to be warm. If there is a real danger of freezing, that's the only reason to consider this additional expense.

Ron Schroeder_2

Hi Paul,

I have seen a digital timer that fits in an electrical box to replace a wall switch at Sears and Home Depot. It runs on a small internal battery and will switch both 120VAC and up to 24VDC loads. Check the back of the package for the specs. Shocked the heck out of me when I saw the ratings.

Ron

Paul_35

timer

Hi Duncan,
I did the same search and did not find this unit.....as a matter of fact, I was asking because I was surprised to find so little....

Thanks for figuring out what I couldn't and posting the link!
/Paul

Paul_35

Best way to conserve energy

Hi Chuckles, I thought about running the circulator pumps but got stuck on two things: How does one get circulation if the zone valves are closed? The other point is the 5-zone issue. Only two of the zones really need this 'timed' warmth. The other 3 zones are separate from confusion by the stove.

I agree whole-heartedly with your point on energy use. My feeling at this stage of pondering [and I am very happy to hear thoughts otherwise] is getting the rads hot between the hours of 12am to 7am must use a lot of energy; again, by 12am, they are as cold as ice. I am wagering that spreading that energy over the length of a day a few [say 12] minutes an hour will cost as much and deliver warmth while we are awake to feel it. I may be totally wrong.....
The other point on this is our use of the aforementioned woodstove. If someone is in to stoke it, it burns all day. But in the event [which happens a couple times a week] nobody is around say 11-3pm, bang....we get hit again with the ramp up. This point was very important last winter; it may become much less important soon, as I have just purchased a coal stove to replace it. This biggest difference here is the coal stove is designed to run for 30 hours on one feed so should conceivably stay running for the heating season.


If in the end letting them go cold were the best way to operate the system, wouldn't an antifreeze additive handle the freezing lines issue?

Thanks to all for the great thoughts,
Paul