Vacant winter house: drain traps

RV antifreeze in all the traps but I leave the heat on a bit. My alarm system monitors the temperature and calls in if the temperature goes below 4C.

I worked with a traveling construction superintendent that had a house in Minnesota. He and his wife traveled together he did two things to protect his house. They had a house cleaner come in once a week to clean and check on the house, she gathered the mail and sent to ther current location. He also had a large red light in the front window that would come on if the temperature in the house dropped below a certain temp, the his neighbor would call and let him know.

Snowman9000 wrote:
Interesting tidbit about evaporation of RV antifreeze. This matches my experience, that RV antifreeze evaporates almost as soon as water.

The evaporation rate of a liquid is directly proportional to its vapor pressure. At 25 °C the vapor pressures for water, pure propylene glycol and pure mineral oil are, consecutively, 24 torr,[2] 0.1 torr[3] and <0.01 torr.[4] Be aware though that the properties of "RV antifreeze" which has propylene glycol in it will be different than pure propylene glycol because alcohol, water and other ingredients are in it. One manufacturer of RV Antifreeze gives the vapor pressure of their product as 17 torr at 20 °C.[5] This material, if placed in a drain, will evaporate almost as fast as water. Some makers of RV Antifreeze will list the vapor pressure of their product as 0.1 or <0.1 torr. This however is only for the propylene glycol component, not the mixture that comprises their product which can be mostly water.

https://en.wikipedia.org/wiki/Trap_primer

:h

For over 20 years I used RV antifreeze in my cabin with never an issue of evaporation in the traps. I would let the cabin go cold though.

Currently I have a bucket mouse trap in the garage I leave all winter. It has RV antifreeze in it, with no evaporation issues to speak of. My 2c is I would not be so concern with evaporation as much as I would be with freezing temps. Not all traps are easy to get too to repair. RV antifreeze is less then $3 a gallon. Cheap insurance in my books in case of a long power outage.

Snowman9000 wrote:
You can buy pure propylene glycol at a farm store, about $20/gallon.

I'm about at the point where I'm just going to forget about the whole thing. I wouldn't be surprised if that's what most people do.

Probably the best bet. We don't worry about it, only problem that I've had was with a toilet trap that was drained caused by the pump in the basement (that pumps up the wastes to the main drain then into the septic system) running continuously because the float valve failed. I have to let this pump run because of the condensate draining from the high efficiency furnace (I leave the furnace on at 50F).

You can buy pure propylene glycol at a farm store, about $20/gallon.

I'm about at the point where I'm just going to forget about the whole thing. I wouldn't be surprised if that's what most people do.

Interesting tidbit about evaporation of RV antifreeze. This matches my experience, that RV antifreeze evaporates almost as soon as water.

The evaporation rate of a liquid is directly proportional to its vapor pressure. At 25 °C the vapor pressures for water, pure propylene glycol and pure mineral oil are, consecutively, 24 torr,[2] 0.1 torr[3] and <0.01 torr.[4] Be aware though that the properties of "RV antifreeze" which has propylene glycol in it will be different than pure propylene glycol because alcohol, water and other ingredients are in it. One manufacturer of RV Antifreeze gives the vapor pressure of their product as 17 torr at 20 °C.[5] This material, if placed in a drain, will evaporate almost as fast as water. Some makers of RV Antifreeze will list the vapor pressure of their product as 0.1 or <0.1 torr. This however is only for the propylene glycol component, not the mixture that comprises their product which can be mostly water.

https://en.wikipedia.org/wiki/Trap_primer

pawatt wrote:

NanciL wrote:
We live at elevation 3200 feet in the NC mountains where many nights and days it is well below freezing and belowzero.
I shut the breaker to the water heater off and drain it.
I drain all the water pipes( I have low pint drains) and then I put regular auto antifreeze in the traps. It won't evaporate like Rv antifreeze.

Jack L

Don't use regular antifreeze, it can poison your water supply.

It can't get into my water supply.- Please tell this old plumber how ????
I started using it about 15 Years ago when I came home to find that the regular RV antifreeze had evaporated.
And yes, I have a thirty year old septic tank and the small amount that goes into it has never hurt the bugs yet

Jack L
I'll continue to use it since it works so well

pawatt wrote:

NanciL wrote:
We live at elevation 3200 feet in the NC mountains where many nights and days it is well below freezing and belowzero.
I shut the breaker to the water heater off and drain it.
I drain all the water pipes( I have low pint drains) and then I put regular auto antifreeze in the traps. It won't evaporate like Rv antifreeze.

Jack L

Don't use regular antifreeze, it can poison your water supply.

Yes - regular auto antifreeze is toxic. It should not go into systems that go to either septic or municipal sewage systems. A good amount of RV antifreeze in the drains and toilets works well.

NanciL wrote:
We live at elevation 3200 feet in the NC mountains where many nights and days it is well below freezing and belowzero.
I shut the breaker to the water heater off and drain it.
I drain all the water pipes( I have low pint drains) and then I put regular auto antifreeze in the traps. It won't evaporate like Rv antifreeze.

Jack L

Don't use regular antifreeze, it can poison your water supply.

FWIW, I used V-oil once in a rig that I leave south. When I came back it was a goo that was a mess to clean (this was in the RV toilet.) I ONLY use RV antifreeze now. YMMV