There should be a drain in the boiler in the basement. You may have to manually open zone valves or other valves, but drain the boiler at it's base.

Also, turn off the electric to the boiler before doing anything and close the auto fill water valve to the boiler so it doesn't try to refill. Opening any vents at the radiators will aid in draining them.

You need to do more to the toilets than just flush them...

You need to add antifreeze to the bowls so that the water in the trap doesn't freeze and break it.

Go with a non-toxic or less than toxic anti-freeze.

The same with the sink, bathtub/shower, and any stand-alone washer drains.

You can also use a plunger to force all the water out of the P traps - It works pretty well on the toilets too, if you take your time. You'll know when everything is empty because there won't be any water pushing against the plunger

Don

"You can also use a plunger to force all the water out of the P traps - It works pretty well on the toilets too, if you take your time. You'll know when everything is empty because there won't be any water pushing against the plunger"

And then you need to fill the traps with antifreeze to keep sewer gas out of the house.
If they are being foreclosed, why are you worried?
The place is going to belong to the bank soon.

I'll be closing down my farmhouse in Maine within the next few weeks. We do this some winters but not others, depending on anticipated winter use and I've done it successfully nearly 20 times over the years, with only a few glitches in the following springs.

Some notes from my "shutdown procedure":

1. Turn off the main water valve (also cut power to the pump if the house is served by its own well).

2. Turn off the valves to toilets and flush each one to drain the toilet tanks. Then reopen the valves to help the supply pipes drain.

2. Begin the draining process by opening every potable water valve you can find (i.e., all basins, tubs, showers, etc.). For "combination valves", put handles in the middle position so that both cold and hot are open to some extent.

3. Turn off the valves to toilets and flush each one to drain the toilet tanks. Then reopen the valves to help the supply pipes drain.

4. To drain the hydronic heating system, begin by turning off the power at either the circuit breaker or the "red switch". (I prefer the circuit breaker since some "red switches" control only the oil burner and can leave transformers, circulator motors and/or supplemental fans with power.) Open the boiler drain valve as well as any drain valves installed in the zones/loops. Manually set zone valves into "open" position.

5. If there is an electric hot water heater, turn it off at the breaker and open drain valve at bottom of heater. Do this early in the draining process as it will assist in draining all hot water pipes.

6. Open any hose bibs on the outside of the house. Also make sure both valves hooked to the washing machine hoses are open. (These are normally open, but just to be sure...)

7. While the water is draining, search the basement for "stop and waste" valves and loosen or remove the caps on these. (Some may be at low places in the piping that won't otherwise drain.)

8. Locate every plumbing trap in the house. It isn't just the toilets and basins, but may include floor drains, the washing machine, etc. Buy some non-toxic antifreeze. (This is NOT the same old "Prestone" you put in your car.) The stuff is expensive, and an alternative is the blue "RV" antifreeze. I don't use that stuff, but under the circumstances, YMMV and you might save a few bucks.

9. Use a plunger to push out most of the water in the toilets and traps. Then add antifreeze. I use about a quart per toilet, a little less for a bathtub and quite a bit less for small basins, etc. A 1 1/4" or 1 1 1/2" p-trap gets about a pint.

10. Put about a pint of antifreeze in the washing machine, turn the knob to the end of the rinse cycle, and start the washing machine briefly. This should pump the antifreeze through the pump and into the trap. Turn off washing machine.

11. You can use a similar process for the dishwasher. I also remove the kick panel and unhook and manually drain the solenoid valve. (I got burned on this one year and had a burst solenoid the following spring.)

12. Allow several hours for the system to drain. Assuming you've allowed the draining to happen for at least an hour or so, start going around to each radiator and look for vents. (You may need a little "key" to turn them, depending upon type.) The more air you can admit into the radiators, the better. Also, it helps if you can open a valve at both the supply and the return end of any heating loop.

13. I do one additional step that you probably won't be doing under the circumstances: I use an air compressor to blow out the heating zones. (I have a four-zone system, and this takes a while, but it's surely worth it to me.)

Sorry to hear about the foreclosure but I think you're doing the right thing here. Sure, the bank may soon own it, but foreclosure doesn't necessarily make for an "even" settlement. You're doing the responsible thing, IMO.

You're very thorough, Tom.

I still hook up a compressor (or even a tank of nitrogen) and blow all the water lines.
Many older places have dips in supply lines that can hold water unless it is forced out.
Houses built to be easily winterized often have extra valves and pitched supply lines for easier draining.

I have used a wet-dry shop vac to help empty commode bowls and traps. Also to drain pipes.

And by removing all the water from a trap, you are allowing sewer gas to freely come up into the unit. Not the best idea unless you replace the water with antifreeze.

No advice, (I'm from the South), but just wanted to say I'm sorry for the foreclosure.