Dual Intermatic P1353ME Timer Installation - Wiring Questions

[jsbatch]

I plan to upgrade my existing pool 'automation' system by replacing two existing Intermatic T104 240V mechanical timers that now control ON/OFF events for two Pentair WhisperFlo WP-4 single-speed 240V pumps (filter & floor cleaner) with two new Intermatic P1353ME digital timers. My desire in this upgrade/installation scheme is to control multiple daily ON/OFF events for the two WP-4 pumps - plus a third Pentair 240V booster pump that feeds a water feature - with ONE of the P1353ME timers. The second P1353ME timer will control an Aqua-Cal 240V heater, 120V/400W pool light and 24V landscape lighting (via a switched transformer). I will install Intermatic 178PA28A freeze protector sensors to both timers and an Intermatic PA122 water temp sensor. I will also install the Intermatic PE650/PE950 I-Wave wireless remote control system to control all of the various functions remotely.

The two existing T104 mechanical timers are wired with dedicated Line/Load conductors (2 each) to supply 240V to the two pumps (filter & floor cleaner). The third water feature pump is fed 240V via a double-pole breaker with the water feature pump ON/OFF functions controlled by a (failed) AquaDyne 240V X-10 controller mounted and wired into the load/control center. The failed AquaDyne X-10 controller is the primary cause & motivation for the new Intermatic 'automation' upgrade\installation.

After MUCH time spent studying the Intermatic P1353ME installation manual and the Intermatic-recommended wiring diagrams for the seven different P1353ME programming modes, I am still puzzled/confused by the wiring needed for the dual P1353ME timers in the contemplated and described installation.

The only way I see to wire ONE P1353ME to the THREE 240V pumps is to jumper the 240V Line from terminal #1 to Terminal #3,5,7 and run the Load from Terminal #4,6,8 to each pump. IINM this wiring approach will switch just ONE leg of the 240V circuit running to the three pumps leaving all three pumps 'hot' with 120V on one pole when switched 'off' at the timer. All three pump circuits are all protected by double-pole circuit breakers in the load/control center and the pump wiring runs from the load/control center to the three pumps in water-tight flexible conduit.

My major question/concern with this wiring approach is will switching just ONE leg of EACH 240V pump circuit create safety hazard in the occasionally-wet environment of the equipment corral?

Does this wiring approach violate code or typical convention?

Can anyone recommend a better/safer wiring approach to accomplish my goal of wiring all THREE 240V pumps to ONE P1353ME timer?

For reference, tomorrow I will snap and attach to this thread a pic of the existing T104 installation and the existing wiring in the load/control center.

Appreciate any and all help/guidance from the sage TFP wizards!!

 

[JasonLion]

Switching only a single leg of a 240 volt circuit is not preferred, but it is allowed, and is frequently done. Unless you add another timer, or control fewer devices, you have no other choice.

I believe the wiring will need to be a little different than what you describe. The way you describe the wiring all three pumps would need to be on a single circuit breaker, which you certainly do not want to do. You want to keep each pump on it's own breaker. That should be a simple enough change to figure out.

This is neither here nor there, but why run the heater from a timer?

 

[jsbatch]

Switching only a single leg of a 240 volt circuit is not preferred, but it is allowed, and is frequently done. Unless you add another timer, or control fewer devices, you have no other choice.

I believe the wiring will need to be a little different than what you describe. The way you describe the wiring all three pumps would need to be on a single circuit breaker, which you certainly do not want to do. You want to keep each pump on it's own breaker. That should be a simple enough change to figure out.

This is neither here nor there, but why run the heater from a timer?

Thanks for the quick input!

Yes, more wiring diagram study and thought tonight produced a wiring approach that (I think?) will feed 240V from each dedicated pump circuit breaker to each of the three switched circuits of one P1353ME timer. I can supply 120V line power to both timers (the P1353ME timer line input voltage is switchable between 120V/240V) with the single poles of another 240V breaker available in the load/power center - or replace the DP 240V circuit breaker with two SP 120V circuit breakers to feed 120V line input to the two timers.

We are located in Cave Creek, AZ - a far north valley foothills suburb of Phoenix, AZ. Our property is situated at ~2600' MSL. We don't winterize or shut down our pool over the winter months and we do experience occasional overnight hard freezes during the winter months that can last several days to a week or more. So, the primary intent to control the heater with the second timer (along with lighting) is to produce heated water when the freeze protection circuits trigger. When the freeze protection triggers and the three pumps start I also want the heater to start (via the timer fireman switch) to raise and maintain the water temp at 36F. Connecting the heater to the second P1353ME timer dedicates the fireman switch function to the heater and also produces the convenient ability to control the heater thermostat (and water temp) via the Intermatic I-Wave wireless remote control that connects to both timers.

I think that the Intermatic P1353ME/PE650-PE950/178PA28A/PA122 automation system will operate pretty slick - if I can get it wired and programmed properly! All in I will have ~$875 invested in the Intermatic I-Wave wireless automation upgrade - that all fits into my existing load/control center and (I think?) can be controlled with a unified Z-Wave home automation system like the new VersaEdge. I can't accomplish the same goals with any other pool automation system for less than ~$1200 - and those options all require replacing the existing load/control center and a complete load/control center re-wire.

 

[JasonLion]

One thing to watch out for when heating very cold water: circulating very cold water through the heater can cause condensation, which if done frequently can eventually lead to corrosion.

 

[Billrector]

Sent you a PM