Boiler condensate freezing in my setptic line

oak

I drain my TT Prestige boiler effluent by gravity into a trap protected sink drain where it travels to the septic tank. Problem is that the trickle of acidic water is creating an ice dam in the 4" drain. The DWV - unfortunately - is not below the frost line due to the shallow depth of the septic tank (its about 18" below grade to the tank inlet) - climate zone 6 (south side Great Lakes).

I could wrap a heat trace tape around the DWV but I would rather not use electricity to solve this problem. I see in the UK there is a product called CondenseSure that claims to defeat the ice build up caused by the steady trickle. It uses a no-electricty, siphon process to hold the condensate until it accumulates 500 ml (about 1/2 quart) and then dumps it in bulk.

https://www.worcester-bosch.co.uk/homeowner/system-solutions/condensesure

Can someone suggest a North American product to do this or an alternative? Maybe something home made?

Those Limeys don't have the cold like us Yanks so I would like a solution that holds two quarts before engaging the dumping stage of the cycle. I checked with a couple of condensate pump manufactures for a programmable (timed) pump controllers but their's work on a steady pumping schedule (as soon as small quantity of condensate is detected) and even the smallest (1/50 Hp) are too powerful (overkill for my situation).

SWEI

A properly sized condensate pump should work, but would require at least some electricity. For a purely mechanical solution, I'd look for some kind of reverse-acting float valve. Might try an ag supply?

icesailor

First of all, it is probably illegal in your state to be wasting acidic condensate water into your septic system unless you have neutralized it first.

Second, I doubt that the condensate waste blocked the sewer line. It is more likely a toilet/s with water leaking slowly bye in the toilet tank. Your leach field should have a 4" vent on it to let air flow over the field and septic tank where the biologics in the tank stay warm, and the air flow from the venting keep the pipe warm enough to stop freezing. If you have any kind of dips in your drain, it will frost freeze. If the whole line is pitching properly (1/8" per foot), it should drain. A load of warm washing machine water will thaw the freeze blockage. Unless there is a dip (trap) with water. Is there covers that go to ground level over the entrance and discharge of the septic tank? Have you checked the crust? Has it backed up in to the drain by flowing under the baffle? Is the leach field flooded?

It isn't backing up because of the small amount of condensate water.

oak

NY code and model code do not specify that condensate be pretreated (i.e for low ph). Pretreatment may be locally required if the drain was to a town sewer, but its not in this case. I am otherwise compliant with code and recommended model code.

I asked a biochemist who concluded residential condensing boilers do not produce sufficient quantities of low ph effluent to affect a 1000 gal septic tank performance when the house is occupied and diluting the condensate with normal volumes of waste water. If fact, it seems that ph treatments are now considered suspects in leach field clogging due to particulate lime stone (the neutralizing media) washing into the system.

I would prefer an off the shelf solution. But I will muse about jury rigging something with a reverse acting float valve.

icesailor

Trust me when I say that Massachusetts "Title V" regulations are far more advanced than any NY "Model" code that allows any jurisdiction to make any changes they wish. With Massachusetts "Title V', you can only make it stronger locally, not weaker. I have a daughter that lives in Easthampton, LI. What is allowed there would never be allowed in coastal Massachusetts.

You should see the creative landscaping designs for mounted leach fields to keep the separation from the bottom of leach fields to groundwater. South Coast of Cape Cod, Dennisport, Harwichport Chatham and Harwich. Something to see.

Ask your Biochemist what unrestricted chlorine use in toilet tanks does to the flora and fauna in a septic tank? Bleach kills AIDS. Bleach also has a negative effect on aerobic and anerobic bacteria.

I don't know where that factoid came from about calcium carbonate grains fouling leach fields. They normally fall out of suspension in the Septic Tank and drop to the bottom to become part of the sludge. Its the phosphorus and potash from detergents that end up fouling leach fields. If New York is still allowing Pits and not requiring fields only, they are behind. They don't want hydraulic effluent pressure driving effluent out of the leach field and into the soil.

Don't get going on flushing old prescription medicines down toilets into septic systems, or what's excreted in the body. Ask your Biochemist friend about THAT.

SWEI

Oxygen bleaches (aka peroxide) selectively kill anaerobes. This (in small quantities) is actually a good thing for a septic system.

oak

Looks to me like the push to treat residential condensing furnaces’ and boilers’ effluent might come from some mistaken ideas about what is contained therein. Nitric and sulphuric acids are the corrosive and so dangerous combustion products of gas and propane. They go up the stack, not to the condensate stream. Carbonic acid is what condenses out of the boiler and it is mildly corrosive if not diluted, so it should plumbed out with plastic, not metal. It gets sufficiently diluted in residential septic systems to not need a ph neutralizing solution. Where as commercial boilers produce quantities that need special handling.

As for limestone clogging septic, its on this wall.

SWEI

Don't forget that there are still a lot of cast iron drains out there...

icesailor

"" As for limestone clogging septic, its on this wall. ""

Is that "Septic Tank" or "Leach Field". Anything lime Limestone is promised to have been removed and dropped into the sludge at the bottom of the tank. When that separated waste water goes under the baffle, It's supposed to be almost safe enough to drink. Once it goes through the graven at the bottom of the field in a Title V Mass. System, it is said to be almost ready to drink.

Not by me.

Jamie Hall

icesailor said:

"" As for limestone clogging septic, its on this wall. ""

Is that "Septic Tank" or "Leach Field". Anything lime Limestone is promised to have been removed and dropped into the sludge at the bottom of the tank. When that separated waste water goes under the baffle, It's supposed to be almost safe enough to drink. Once it goes through the graven at the bottom of the field in a Title V Mass. System, it is said to be almost ready to drink.

Not by me.

Nor me! Nitrate levels are still much too high! But a properly designed and built system does a remarkably good job on the little buggy things...

But the tiny amount of limestone which might get in isn't going to be a problem.

icesailor

Agreed. But the huggers of trees consider it right up with the evils of Lucifer.

Zman

I would agree with the recommendation of an inexpensive condensate pump.
I also suspect that there is a low point in the sewer line which is contributing to the problem.
Digging up the line to adjust the pitch then insulating might be a better long term solution.
I am sure the legislators in Massachusetts will write a law to address this soon. That way the rest of us in the country will know the right way to do it...

icesailor

"" I am sure the legislators in Massachusetts will write a law to address this soon. That way the rest of us in the country will know the right way to do it... ""

They already have. Its in the latest version of Title V septic regs.

What seems to have passed right by is that there are probably toilets that are leaking by at night that allow this freezing to go on. Sewer pipes in the road don't freeze. There's a lot of latent heat energy in sewers. Every house on a sewer system vents the sewer. I've never heard of a septic tank freezing. The biological action creates heat. If it didn't do it last year, why is it doing it this year?

When you go to bed, shut the valve off to the toilet so it can't fill the tank. If the water has drained out overnight, it is going slowly into the septic tank and through the building drain outside.

The only time I have ever heard of this happening is in houses with leaky faucets or toilet flush valves.

Zman

I have seen exactly what he is described in several homes. I do think it is a bit unusual in a home that is occupied full time.Usually the problem occurs in second homes in years when the snow cover is thin and temps are cold.

kcopp

I believe (at least here in NH) that code requires you to have a minimum of 4' of cover on the sewer drain OR if that is not possible to insulate the drain to make it so. Long term then in the summer dig up around it and put 2" of blue board on top of the pipe. Or the condensate pump added and then dump it on the ground outside.

Code ... P. 309.5 boca code.

But even if its not code it is a solution to a problem.

icesailor

kcopp said:

I believe (at least here in NH) that code requires you to have a minimum of 4' of cover on the sewer drain OR if that is not possible to insulate the drain to make it so. Long term then in the summer dig up around it and put 2" of blue board on top of the pipe. Or the condensate pump added and then dump it on the ground outside.

Find that in a code. Because of the physics of cold, you would make much of every Northern tier state unbuildable if groundwater is ever an issue. In some places in New England (like Massachusetts) you need 5' to 10' from the BOTTOM of the leach field to groundwater. His problem is and is not unique. How many people in your area have you heard about that have frozen sewers? No matter how cold it gets? It isn't Millions, it isn't thousands. And whatever it is because they have water continuously running through the drain at low flow quantities.

If you can't be bothered with shutting off the valve overnight, put some blue dye in the toilet tank before you go to bed. Don't flush the toilet during the night. If the water in the tank is clear in the morning, the water is leaking out. Especially if you put bleach tabs in the toilet tank. It destroys tank flappers. Which is another issue. All 1.6 GPF toilets have specific flappers that go that specific flush valve. Kohler toilets are very specific and sell ones that work in their specific models. They have tried to use Fluidmaster flappers and they don't work. They had to go back to their own specific models. If you go to Lowes or HD, they sell Kohler toilets but no Kohler specific toilet parts. That don't fit.

Pull out the flapper. If it looks like a prune, it needs to be replaced. One load of wash or dishes washed will melt any ice in the pipe.

A 10# bag of ice in the refrigerator freezer at 10+ degrees is 10+ degrees in the bag as ice. Put the ice in a large pot. Fill the pot with tap water, we'll call it 50 degrees. The ice temperature IMMEDIATELY goes to 32 degrees, and so does the water. The ice will melt in the pot until there is no more ice. The ice gives off heat until it is melted. Or, how you check a thermometer for accuracy. It must read 32 degrees in ice water.

That excess water that is freezing in the sewer pipe came from somewhere. You might have roots, and some form of blockage. But you are leaking water in the house.

And if you are on metered municipal water, clock the meter. Its coming from somewhere, and you know where it is going.

pattersonheating

Live at 8000 ft in Colorado and run into this problem all the time. Both on city sewer lines and septic tank line. Frost level is 6' plus during winter. Nearly always happens on condensing boilers or furnaces. Always seems to happen when no one is around flushing commodes, etc. A $ 40.00 condensate pump that sends the condensate thru as a quart shot of liquid solves the problem every time. On new installs we install them religiously.
Heating Guy

Mark Eatherton

I too have a house at 8,000' ASL (also in Colorado), and I too had my shallow sewer main freeze up out in the yard. That was about 5 winters ago. I realized in short order that it was the continuous trickle from my mod con boiler, so I installed a 5 gallon bucket with a sump pump controlled by a ball switch with mercury in it, with neutralizing agent in the bucket, and when the bucket gets full, the sump pump turns on and QUICKLY ejects the condensate out to the septic tank. I've not had ANY issues since doing so.

Might be considered over kill, but I have NEVER been accused of under kill…

Pump and dump from a sump and avoid the ice hump.

ME

icesailor

Another simple resolution to a simple problem.

If it happens again, check the toilet tanks. If you see "legs" in the bowl, its leaking.

Mark Eatherton

I've used blue food die in the tank to see if the flapper is leaking. If the refill tube is too far into the over flow tube, some older ball cocks will allow them to siphon water out of the tank and into the bowl. If you see blue in the bowl after having had let it sit for a while, you need to see RED (Korky silicone rubber flappers are red). I had my leg in a toilet bowl once. It was in a hotel, and I got hit with a blast of hot water that wanted to take my skin off. I JUMPED to get out of the way, and ended up with one foot in the toilet bowl… Never went back to that hotel (Anaheim)…