Next Big Challenge: What Tripped the Pump Alarm?

Onsite investigator diagnoses then fixes a system malfunction at a summer cottage.

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There is nothing like a slow pontoon boat ride around the lake on a warm, bug-free evening at the end of summer. The sunsets are beautiful and – when enjoyed with cold adult beverages – it makes for an ideal evening with your friends and neighbors.

Nothing destroys that idyllic picture faster than pulling up to the dock at the end of the ride and hearing an alarm buzzer going beep, beep, beep. Everyone wonders what that noise is, except an engineer/onsite installer trainer and the owner of the cabin where the boat is docked. It is the tank alarm going off, indicating that the water level has risen above the normal pumpout depth, meaning there is a problem with the pump in the pump tank.

MAKING THE DIAGNOSIS

After a night of very restricted water use in the cabin and using the neighbor’s bathrooms, there was the opportunity to investigate the cause of the backup and the alarm. As is often the case when troubleshooting, more than one factor contributed to the problem.

A couple things were evident upon opening the tank and investigating the contents. First, the bottom of the tank had a sludge accumulation over 8 inches deep. This was covering the bottom of the pump. More distressing was discovering that the pump was a standard clear-water sump pump, not the appropriate pump to convey sewage effluent from the tank to the drainfield.

As pumps in our systems have become more common over the past 30 years, the first rule we highlight is that sump pumps found on local hardware store shelves are not appropriate for every job. One of the first keys to a “good” system that will last a long time is selecting the proper pump for the application.

Talking to the cabin owner, it was determined the septic tank was last pumped in 2005. That’s also when the current pump was installed and some other repairs were made to the system. For the first few years after that maintenance, the cabin served as a full-time residence and since then has been used seasonally.

These circumstances make the case that both the septic and pump tanks need to be checked on a regular basis, and certainly the septic tank needs to be pumped on a greater than 10-year frequency. It was interesting it had gone that long because the county has a program where septic tanks should be checked if not cleaned every three years. If this had actually been done, at least the problem with the sludge could have been avoided.

FIXING IT RIGHT

The first order of business was to get a service provider to pump both tanks, then remove and replace the pump. Since the pump in this case moves effluent to the drainfield where it then flows by gravity, a single-stage low-head effluent pump was installed. The only critical requirement is that it be able to deliver flow faster than water from the household appliances enters the tank; so it must deliver more than 10 gallons per minute.

The new pump was set on concrete blocks in the bottom of the tank to raise the pump intake off the bottom and away from solids that may make their way into the pump tank.
Back at the outlet of the septic tank, an effluent screen was placed to keep any of the larger solids from entering the pump tank. Effluent screens are now required by the county where this system is located.

One more correction was made to the existing installation. The power connection for the pump was located outside the pump tank in a 4-inch PVC pipe, but it was just a normal indoor receptacle dangling inside the pipe. This was a sure way to experience problems. And upon investigation, the sump pump failure also took out the circuit the pump was hooked to. Wiring to the pump tank needed replacement before the unit was operational.

ANOTHER DAY IN PARADISE

Something we stress all the time is to install electrical connections outside the tank in an above-ground weatherproof box or in the house or the garage. All connections in the tank should be watertight or soldered, and no plugs or sockets should be located inside the tank where they will quickly corrode and be rendered useless.

After just “another day in paradise,” it was interesting to reflect on a couple of things. First, all of the problems could have been avoided if good installation practices were used. Second, those practices have been known for a long time and true professionals should be using them. Third, the situation is a reminder that just about the time you think you no longer need to cover very basic information, along comes something to prove you wrong!



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