Hi guys!
Tom, we're talking about a sewage ejector here, so battery back up sump pumps won't work here! And, just FYI, in my opinion, battery back up pumps are definitely old school and outdated as of late! Here, these deep-cycle marine battery with power inverters are the only way to go as they allow the user to use the powerful pumps in place and do not rely on the smaller back up pumps or require installing the new pump in the sump pit or ejector pit (or lowering the pit to accommodate the new pump).
Ncrobino, check out this article of real time experience with these inverters I am talking about. The technology isn't so new, but using it for home appliances/pumps is pretty new so not so surprised to hear that your local plumbers may not be on top of this stuff...;)
Power Inverters | Power Inverter Review - Consumer Reports
Note here that the inverter they use are in this article is a max. 1500 watt and under $200.00. The inverter I mentioned using here would probably be around 5000 watts or more and as mentioned earlier, would cost more ($500.00ish). Also note that these guys are not talking about a deep-cycle marine battery....they use their simple car battery in the examples.
You can also click on this link from the inverter store...call them up and see exactly which inverter they recommend for this application:
Power Inverters and Solar Inverters for Home and Businesses - The Inverter Store
Finally, to answer your questions:
Yes, the leak guardian shuts off the water supply to the entire house if you are home, or not home, so really a smart investment to protect your home 24 hr/365 days a year!
Correct, no opening of the pit for an inverter installation. Here, you install the deep-cycle marine battery (or two if you really want to be protected for worst case) on a wall near the pump and then install the inverter to the marine battery (about $100.00 each by the way) which keeps the battery "trickle charged" at all times via the 120 outlet the inverter plugs into and then you plug the pump into the inverter. When power goes down, the battery is fully charged and inverts the 12V power in the marine battery to 120V and runs the sewage ejector, or sump pumps, or refrigerators, etc...;)
Check into it and then come back and give me that hug, OK? :)
Mark