I am trying to create some redundancies for a small commercial ice maker to prevent there from ever being a flood in my garage. The ice melts from the ice bin (which holds around 80lbs of ice) constantly and gravity drains from 3/4" PVC into a condensate pump a few inches away… If/when the condensate pump fails, I plan to have a float switch open, breaking the connection at the DPDT relay and turn off the ice maker (to prevent more ice than what is already in the bin from being created) as well as close the newly installed inline motorized Taco zone/ball valve. Any melting ice will then stay in the ice machine with the valve closed. The Taco valve would also close in a power outage (being that the valve is N/C) so that the ice did not end up melting and draining with no power to run the condensate pump.
Planned install: The c & w/y terminals on the Taco valve would be wired directly to a 24V transformer. The two end switch terminals on the Taco valve would be wired to one of the common and one of the normally open terminals on a DPDT Relay (which is controlled by a 24V normally closed float switch). When the float switch activates (opens), the Taco valve would close. In the event of a power failure the Taco valve would close. See crappy diagram I made below.
So I think I have that all correct, but was wondering if I should try to build in a 2nd float switch to prevent any chatter at the motorized ball valve and not sure if there would be negative consequences if the ice machine ever received 'flickering' power? I think the situation I would need to worry about the most is an extended power failure that turns the ice in the bin to water... When the power comes on, I fear the condensate pump would have trouble keeping up with a mass flow of water (although it is a 270GPH pump with 1G tank). My assumption is there would be several 'trips' of the float switch as the pump worked to remove all the water. My thought was installing low and high float switches on the condensate pump. The ball valve would close and ice machine turn off when both switches were open and the ball valve would open and ice machine turn on when both switches were closed. Not sure how that would be wired though???
My other thought, and this may actually be a better solution is to just use one float switch, but if the float switch ever opens it would essentially 'trip' the circuit (closing the ball valve and turning off the ice machine) and require a manual reset. This really seems ideal to me as someone would have to be present to inspect why the float switch was triggered... I have absolutely no idea on how to best implement this (with my limited electrical expertise). I've seen latching relays mentioned from Google searches, but I am unfamiliar and not even sure if that would be the best approach. Any ideas on how to accomplish this would be very helpful!!!
Normal state - Ice machine powered, NC motorized ball valve powered.
High float state - Ice machine no power, NC motorized ball valve no power.
Notes - Store the high float state if triggered. After high float state is triggered, require a manual reset before the ice machine and motorized ball valve receive power again.
FYI: Ice machine pulls around 5-6amps at 120V. Ball valve does around max .5 amps at 24V. Planning on also using the 24V transformer for relay(s).