30 day Vacation - How much setback

StudyingHard

can I do?  Thinking about setting the tstat at 40 deg.   Overnight lows are around 20

with some droops down to 10, and a few occasional spikes down closer to zero.

(southeast Colorado, on the plains)



After the first cold firing, I presume the system will cycle like it normally does:  On the pressuretrol until the T'stat is satisfied, then rest until mama nature sucks the heat out again.



System is two-pipe, with vacuum vents; yes, it does pull a minus-8 psi when cooling down, then leaks back to zero in about 4-5 hours.



Going where it is warmer :-)



P.S. I'm self-retired (i.e. self-unemployed), so no need to get jealous over the 30-day thing.  Just snow-birding  :-)

nicholas bonham-carter

setback

can your thermostat go that low? i would be worried about temperatures that close to 32 deg. so would go down to 45.

i am also amazed that your vacuum system is able to hold negative pressure for so long. bon voyage.--nbc

StudyingHard

Three Hoffman 76's

at the ends of the two supply mains, and at the conjunction of the three dry returns (just before they drop 15" and connect to the end of one of the supply mains (oops, gotta fix that!).

StudyingHard

Thermostat is

a simple Honeywell heat-only (two wires, switched open or closed),  It actually bottoms out in the lower 40's.  I tested it with blasts of cold outside air.   So I plan to just slam it all the way down as I walk out the door.  Thanks for your answers.

Unknown

Winter Vacations

The big consideration is water pipes. If they are in the outside wall, they could freeze if you let the temperature go too low.  You don't want the coldest room to go below 42 degrees especially if you think there's water piping present. Depending on your system, I'd try for around 42 - 45 on the thermostat just to cover your coldest room. Be sure to open all the door under your sinks (or any where you have water piping so that what heat there is, can get in there.



If you plan to take regular long vacations during cold weather  I'd consider draining all the water pipes in your house and drain the boiler and boiler piping.  My next door neighbor goes to the Virgin Islands every winter (He figures he'd rather spend his money there than on heating oil!) and he can shut his house down in about 2 hours.  It's pretty easy if you set it up before hand by adding drains and valves in strategic places on the piping. He opens the drains and then uses a small air compressor to blow out the pipes. In the toilets he uses a brine solution ( He adds enough salt to a bucket of hot water to float a potato) and in the sink traps, where brine might be too corrosive, he uses antifreeze.

- Rod

nicholas bonham-carter

30 day setback

why not get some digital indoor/outdoor thermometers, and place both units near plumbing, so when you return, you can see how low the temp was in critical areas? also if a neighbor is checking, he may see the minimum temp lately, and adjust accordingly.

do you ever have power cuts in your area? if so that might be another reason to stick with a higher temp--nbc

nicholas bonham-carter

vacuum system modifications

just a thought, your vacuum system might be a candidate for a hi-lo-hi modulating burner. when the air is out, controlled by pressure, the burner could drop to 75% and your "sub-atmospheric" system would give even more gentle heat.

just as in the days of coal, and the fire had died down to a few coals, by 5:00 AM, steam still filled the system, although at slightly negative pressure.

this could merit another thread.--nbc

Nick_C

Alerts

Assuming you have a permanent internet connection, you can get a couple of thermometers and perhaps a water alarm for pretty cheap.  They can broadcast temperature (either regularly or if it drops below a particular temp) to an email account.  You can also get similar alarm platforms that will do the same by dialing out over a regular phone line.  It's pretty cheap to do and adds a lot of secutiy for people in your position.