Hartell Pump Malfunction

[ECove]

Hello Plumbing Community,
I'm relative handy but a DIYer and nowhere near a professional so apologies in advance for my ignorance.

Was hoping to ask the group about where to begin with a Hartell LTP-1 pump that seems to malfunction. We have a small wet bar/sink on our main floor that drains to the basement where the pump relays the drainage about 40 or so feet through the ceiling of the garage to the main drain pipe. The problem is, the pump doesn't routinely come on and seems to turn on sporadically/inconsistently. For example, I can run the sink until it fills up with a gallon or two and the pump doesn't come on. The water sits there. Then suddenly, out of the blue maybe 15 minutes later, the pump will trigger on, sucking the water out of the sink and downstream. I can't seem to find a rhyme or reason to why it will come on.

We moved in to this house only six months ago so I don't have any context of how this pump has historically worked. And it seems to have been malfunctioning from the time we bought the house, as that sink has always backed up. We just thought it might need to be de-clogged.

I figured I could start by taking it apart and see if the float is malfunctioning but it doesn't seem like that would be the issue since I know the pump tank is full up when the sink is backed up.

Any advice on where to begin or common pitfalls for this sort of issue?
Thanks in advance.

 

[Geofd]

What else is connected to that pump?????,does it have a screen on the inlet, sometimes if the screen is clogged the sink won't drain until it drains thru the screen,you should be able to open the top, check the length of cord in the float you can also tip the float and see if it activates the pump.you may want to check your check valve to see if it's working properly if it's stick open water will drain back into the tank tripping the float

 

[ECove]

Thanks for the reply Geofd.

There is an inlet from the sink, an outlet to the main drain line and a vent.

I took it apart and no screen on the inlet.

If the check valve wasn’t working properly and there was back-flow, wouldn’t the pump just keep running? My problem is that it doesn’t seem to trigger when it should, when there is water in the sink and the pump basin.

I was able to test the float switch and it seems to work when properly activated when I have it apart. There is a fair amount of scum on the inner ring of the float and the rod that it floats along so I’m thinking perhaps the float goes up, activates pump, gets stuck on the scum and slowly and sporadically slides back down, which might explain how it randomly fires?

My theory so far if that makes sense. I’m going to clean it up soon put it back together and retest.

 

[Geofd]

Or the check valve is slowly leaking by and pumping what's left if there's enough to trigger the float if you give the float and rod assembly a good cleaning your on the right track