We're having a problem with our lake water system. Please let me know
if you have any insight.
3 wire submersible pump, about 10 feet under lake surface plus 15 feet
height (200 ft run) to pressure tank, switch, valves...
For winter operations (in Bancroft, Ontario Canada), when the pump
shutoff is tripped, a valve opens up allowing the water to drain from
the line back down to the lake. This means we don't have to heat the
line all the way down to the lake; just the short run where the line
enters the lake surface.
We purchased the water system with the cottage last fall. Everything
worked fine until...
On New Years eve we arrived (at the frozen lake) and I turned on the
line heater at the shore for 2 hours before turning on the pump. I
left the basement once I saw the pressure in the tank begin to climb.
The next morning I noticed a hole in the ice over top of the pump
location. It seems the pump had been running all night and melted the
hole (from 10 feet under water; 8 inches under ice).
Basic troubleshooting showed that the pump could never again bring the
tank up to the pressure (50 psi) required to trip shutoff. It could
only reach 42 psi.
A month later I returned and again tried to pressurize the tank. This
time I couldn't get the system to reach over 22 psi.
This weekend (well thawed), water barely dribbles into the tank.
Early in the winter, in an attempt to save energy, I turned off the
water line heater at the shore. When arriving at New Years, I turned
on the line heater and let it run for 2 hours before flipping the pump
My initial theory has been that, in allowing the line to freeze at the
shore, the line had split. The theory goes that as pressure increases,
the split opens up and releases pressure such that tank pressure never
grows high enough to trip the shutoff.
A couple of observations seem to dispute this theory. First, pressure
has kept dropping lower and lower. After New Years I left the shore
line heater on, thinking this would prevent further line splitting.
Second, this weekend I was able to examine some of the line at the
shore and could find no water squirting around (though the line is now
under a foot of cold water).
Finally, last fall when everything was working fine, there was a
vigorous disturbance of water over the pump when it was running. This
spring, the disturbance seems to be less vigorous.
I'm now wondering if that first night during New Years, there was
frozen blockage in the line that kept the tank from reaching 50 psi and
causing the pump to run all night. This all night running damaged the
pump such that it can no longer acheive high pressures.
I'm left thinking I may simply have a failing pump. Worse would be
that I have both a line and pump problem.
Does this sound like a failing pump and/or line problem? Any thoughts
or recommendations are very much appreciated.
Also, I'm hoping to DIY my way out of this. Is replacing the pump
fairly straight forward?