Quote Originally Posted by PoolDoc View Post
Offering electrical advice over the Internet always makes me really nervous, but . . . you seem to understand what you are looking and how to use a meter, so here goes.

The fireman's switch circuit you ID'd on the Starite can be connected to any control device or safety, so long as ALL devices are connected in series, not in parallel. In series connections, if any switch fails, the circuit is open (infinite ohms). The circuit is 'connected' or enabled only when ALL switches are closed (> 0.3 ohm)

In millivolt heaters, it is absolutely critical that this circuit must be 'clean' and low resistance, since such heaters operate on tiny voltages and amounts of current. On electronic, transformer driven, heaters such as yours, this is not quite so critical, but still good practice.

It appears that the Jandy has a controlled SP-NO (single pole, normally open) relay in the heater position. This circuit is NOT powered by the Jandy (no voltage), but makes or opens any 24v circuit connected through it. It is NOT to be used with line voltage (>100v) but only with control voltages (<26v).

That said, it appears you can simply unplug the short yellow "fuse" jumper, cut it, and splice it using insulated butt splice connectors.
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The heater cannot shut on without the filter pump running. If the pump shuts off so does the heater. Install guy said that was the way it needed to be and I cannot find anything suggesting otherwise.

The wiring should take no more than 15 minutes. I'll let you know how it went.

Thanks PoolDoc