Electrical – Temporary pinning of sensors to ceiling

There are switches that have motion sensors in them.

There are also Light fixtures that have sensors in them, you would need all new fixtures. If by spot lights you mean recessed lights this may not work.

We had the switch type in a rental once. I may put them in a hall but never in a main room as every few minutes you had to wave your arms to turn the lights back on. I dont remember how far the sensor could see.

One of these will be the easiest way to add motion sensors, if none of these suits you more info will need to be given about the wiring you wish to change i think.

Do you have a link to the type of device you want to install?

I am assuming the sensors in the bathrooms are low voltage, say 24V, and rated OK for parallel operation. Also assuming that the relay that runs the pump is the same low voltage. Generally the sensors will have three wires, positive in, negative / common in, and switched out. Let's say it's black, white, and red.

In the basement, you'd connect the all the blacks from the occupancy sensors to 24V+, all the whites to common, and all the reds to run them in parallel.

Then to run in series with the temperature sensor, you'd tie the reds to the black of the temperature sensor, the white of the temperature sensor to the other whites, and the red of the temperature sensor to the coil / primaray + terminal of the relay that runs the pump.

The white of the coil of the relay that runs the pump would tie to all the other whites. The secondary / contacts of the relay would switch power form the pump.