Questions on Elk M1ZTS / LM34s and other pool automation


Active Member
Well sitting here knowing that i am headed to bed, freezing temps aren't coming for another 4 hours has me thinking i need to get back to automating the pool and after two years of thinking i'm still trying to avoid the cost of the pentair / jandy automation solutions.

Here's my plan (all driven by the elk):

1) pull out the existing solar control (goldline)
2) pull out the existing intermatic manual timer for the pump
3) replace #2 with a manual disconnect which is fed from a contactor controlled from the elk. Right now that contactor is located in a project box with several others far away from the pool pad. So i guess for easy on/off at the pump, i'd need some sort of non-momentary switch to feed a control circuit...
4) currently - no plans to automate the chlorine generator, but i could trigger this off its own contactor as well
5) control the loan 24v jandy valve with a relay (driven by temp rules in the elk)
6) run a on/off control into my hayward gas heater to allow for on / off only (it would still use its own temp sensors in addition)
7) use one M1ZTSR for the rooftop sensor...
8) build a sensor for the pool temp part of it. I found a couple of links that inspired me here: (scroll to the bottom) (claims the elk sensor side is just an LM 34)

1) The Florida temps on ashphalt might exceed 140 degrees. Hoping this will not destroy the probe and that in such an event the elk would still read 140 degrees?
2) can i just buy an LM34 and wire into the M1ZTS and make my own sensor?
3) I like the epoxy / lm34 idea and mounting in the bottom of the pump where my otherone is now, slightly concerned if it failed, it could get sucked into the pumps impeller (pulling the wiring with it)
4) alternatively, If i were to gut an existing probe that enters in the bottom of a pool pump (or a thermistor), is there a good material that would not insulate too much if i tried to remount the lm34 in it?
5) any ideas on the wiring at the pump? disconnect is easy, but what type of enclosure for all the LV stuff? Would like something that looks pretty nice
6) am i being dumb mounting the contactor remotely especially if i might want to add one for the chlorine controller later? Similar to #5, if i mount pool-side, what's best enclosure for the HV side?

Any other ideas / recommendations?

I would mount a number of high-voltage relays in a convenient, but sheltered location. Could be in the pump house, inside your house, etc. Wherever the power lines are. No need to be pool side, could even be at your main panel if things are on seperate circuits.

I've got a ZTS remote probe coated in epoxy, works well. Keep in mind that the elk probes are not linear, meaning they need to be calibrated for every temp range. If you are only going to monitor 70-100 degrees, no big deal. But once calibrated at 70, they can be a few degrees off at 20F.
When we bought our house, it already had an old re-badged Jandy control system. The electronics were dead, it was only the mechanical timer motor that still controlled the pool pump. So I removed the Jandy electronics and installed 2 Elk cards, an input expander and an output expander. The output expander controls the old Jandy relays, so I didn't have to mess with any of the high voltage/high current wiring. It is a nice project box as it has 8 or 10 breakers in the bottom section, a high voltage section for the contactors and a low voltage section for the Elk boards. I added some 3way switches for the pump, heater and blower (auto-Elk/off/manual-on) for local control, for servicing or in the event of Elk failure. It is a nice box if you can find one without the expensive electronics or maybe find a failed one on eBay or craigslist.