Wiring Hayward OmniHub to a Pentair 250M Millivolt Heater

[hutchej]

Morning all, thanks again for all of the quick replies, this is a great community!

I ran the tests both in continuity and ohm mode.

In continuity mode with the heater off:



With the heater switched to on in the automation it starts with the first picture below and settles to the second picture.



In ohm mode starting with heater set to off:

>

With heater set to on in the automation triggers to picture 1 below and settles to picture 2:
>

These tests were conducted directly connected to the wire that is running from LV1 in the Wiring Hub.

 

[JamesW]

You need to test ohms.

The heater switch is simply an On/Off switch.

On should be 0 ohms (closed switch).

Off should read "O.L", which means Open Line or Over Limit.

Try putting the disconnect at the red dot location.

If you use the blue or green location, then you have to have the selector switch set correctly.

Maybe the selector switch is not set correctly?

MASTERCRAFT 052-0055-6 MULTIMETER INSTRUCTION MANUAL

View and Download MasterCraft 052-0055-6 instruction manual online. 052-0055-6 multimeter pdf manual download.

www.manualslib.com

https://media-www.canadiantire.ca/manuals/product/0520055/0520055p-en-fr-604e00cd-1e75-4273-93d8-ea56b6a65f5a.pdf

General PDP Template

www.canadiantire.ca

 

[hutchej]

Well James you had it right!

The key with OmniHub and this heater is to wire LV1 to the 'Off' part of the switch (red dot). With the switch set to pool and the thermostat set to the highest level. Now when I turn the heater on/off in OmniHub it works properly and simply turning up the pump doesn't trigger the heater to turn on uncontrollably. Thanks for all the ideas and the quick replies - it's much appreciated. I'll work on my multi-meter skills going forward haha.