How to keep plumbing from freezing?

[xxclaro]

Asked and was given good advice here earlier this summer about trouble with my septic system, so I'll try again. The pipe from my septic pump comes up to within a couple feet of the surface, has a short horizontal section with a anti-backflow valve in it and then drops back down to where it exits the side of the tank. Its working quite well so far.

I'm concerned that once the real cold sets in, that valve is going to freeze up, either stopping flow or allowing backflow. I thought i would simply put some heat tape on it and all would be well, however all the heat tape I've found says its not for drain pipes that don't generally contain water. I assume the temps get too high on an empty plastic pipe. Anyone dealt with this or know what should be done?

[gmcmax05]

It won't freeze. There is enough heat in the tank to prevent this from happening. If you weren't home for extended period of time during a cold snap I suppose it could. Why do you have a backflow valve there? You should only have a drain hole at bottom of pipe where it exits tank so your line will drain back into tank when pump shuts down.

[Dewey Cox]

Heat tape.

[Drewski Canuck]

If you are within a couple of feet of the surface, is this a new install??? Frost goes to 42 inches in Alberta in a lot of places, so this is very odd.

You could dig down to the pipe, lay a layer of 2 in Stryrofoam SM over the length of the pipe, then re cover to grade, which will help hold the frost back.

Ground temp is 58 F so any barrier will help hold back the frost, and let the ground temp protect your vulnerable pipe.

This was done around the house foundations in Fort Mac Murray to stop frost heaving, quite successfully.

Drewski

[Digger1]

Hi. I spent several years in utilities install and worked for my dad and another contractor doing septic fields. We typically brought the ABS line up from the septic tank pump to about 2 feet below surface in the manhole. Turning horizontal to go out install a union so as to make easy pump removal. At the 90 turning to go horizontal drill a 1/16” hole so when the pump stops air is allowed in and sewage drains back to the pump and out to the field. Drill hole at an angle so it doesn’t squirt you in the face or up at the lid. It usually plugs off while pumping anyway. Nothing left there to freeze and when the pump starts, a big shot of warm goodness blasts happily right on out. No backflow valve is used. I had to rebuild my system here at home a few years ago and it’s working like a Swiss watch. Or at least like a BM. W.

Oh while it was dug up I laid a bunch of old insulation over the pipe outside the manhole where it’s only a couple feet deep. Styrofoam is good too. If I remember this winter, I’ll lay a couple little straw bales over the lid too. Enjoy.

[260 Rem]

I’m not sure what the backflow valve is doing. The simple solution is to drill a hole in the discharge pipe inside the tank. Of course it sprays a bit which is no issue inside the tank, and when the pump quits, effluent can drain back. If you are using water regularly, nothing freezes. If you are going to spend the winter in Palm Springs, have a neighbor run some hot water once a week....or drop in a tank heater on the effluent side.

[Supergrit]

Heat tape and insulate it can't see Why it would be a problem it self regulates it's temp as choose a low wattage tape.

[xxclaro]

Thanks guys. I added the valve this year while replacing the pump, because as soon as the pump shut off it started flowing back through the pump and would keep flowing till the pump had to turn on and pump it down. Would drilling the hole up near the top eliminate that?

[Dewey Cox]

What are you pumping into?
A field, or is it an open discharge?

[xxclaro]

What are you pumping into?
A field, or is it an open discharge?

Its a field. This didn't happen in previous years and I'm not sure if that's due to the high water levels this year ir because my pump is a little lower

[260 Rem]

It will drain back as far as the hole...but letting air in at that point allows the line to siphon the filled line out the discharge end. Not much will be left in the line to drain back into the tank. Sounds like it was originally all draining back through the pump and raising the level enough to activate the switch...hence the repeat cut-in?

[Dewey Cox]

There's lots of septic tanks out there with checkvalves, mostly ones that discharge into a common line for a public sewer.
As long as the manhole isn't sticking out of the ground, and the pipe isn't up too high in the man hole they seldom freeze.
But some heat tape now prevents that possibility when it's -40 and you don't want to be out there.

[xxclaro]

It will drain back as far as the hole...but letting air in at that point allows the line to siphon the filled line out the discharge end. Not much will be left in the line to drain back into the tank. Sounds like it was originally all draining back through the pump and raising the level enough to activate the switch...hence the repeat cut-in?

Exactly right. Check valve was what the pump manufacturer told me to do, but don't think those guys are here in Alberta with our climate. Got a heat tape today and will test it on a piece of abs and see what temps it hits

[gmcmax05]

Thanks guys. I added the valve this year while replacing the pump, because as soon as the pump shut off it started flowing back through the pump and would keep flowing till the pump had to turn on and pump it down. Would drilling the hole up near the top eliminate that?

I have run a septic tank for 20+ years with ZERO issues other than replacing 2 pumps. Last year I replaced my tank & discharge line, I have a pump out not a field. I do not have a backflow valve. The hole has to be drilled at the 90 where the line exits the tank, drilling it up top will not allow the line to drain & you will have freezing issues. Wrapping stuff in heat tape is not necessary, but it's your tank do what you want it's not me out there when it's 35 below lol.

[260 Rem]

The most likely freeze point, should that happen, is in the horizontal section on the “riser”. If you do find it frozen when you get back from a warm weather holiday, it can usually be thawed with some hot/boiling water poured on to the riser

[gmcmax05]

The most likely freeze point, should that happen, is in the horizontal section on the “riser”. If you do find it frozen when you get back from a warm weather holiday, it can usually be thawed with some hot/boiling water poured on to the riser

How would that be possible if the drain hole is drilled at the 90 where pipe exits tank??

[260 Rem]

How would that be possible if the drain hole is drilled at the 90 where pipe exits tank??
I am referring to a riser install like that described by digger ... which I have had freeze after a long winter absence. Didn’t pull the system to do an autopsy but I suspect what happened was that the “drain” hole is very small and maybe got plugged by effluent backflow that was not pulled out through siphon action. I got the “tip” from our local septic guy. Bottom line is it worked.

[gmcmax05]

I am referring to a riser install like that described by digger ... which I have had freeze after a long winter absence. Didn’t pull the system to do an autopsy but I suspect what happened was that the “drain” hole is very small and maybe got plugged by effluent backflow that was not pulled out through siphon action. I got the “tip” from our local septic guy. Bottom line is it worked.

That's where I'm referring to as well. How would it freeze there if you have a drain hole at the 90 where line exits the tank, every thing should drain when pump shuts down. I o away for 2 weeks every Feb & have never had issue with freeze up & I'm near Peace River. I usually pop the lid every once in a while & ensure the line drains when pump shuts down.

[260 Rem]

Yes, it should drain, but apparently sometimes “poop happens”... and since the remedy prescribed by the installer worked, I am confident his advice is sound. Maybe you just need to leave it for a couple of months:)