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Pentair

Pentair UltraTemp ETi Hybrid Heater / Heat Pump

The ETi Hybrid puts a gas heater and a heat pump in one cabinet. It connects exactly like an UltraTemp — relay or RS-485, with a Remote Mode setting to match. The question this guide cannot answer for you is which of the two heat sources you are actually commanding.

It wires like an UltraTemp

The control interface is the same as the standard UltraTemp: a three-wire remote terminal block for dry contact control, or an RS-485 connector for serial control, with a Remote Mode setting on the panel offering OFF, RELAY and RS-485. Set it to match whichever you wired, or the unit ignores both.

SignalColouriSmart Module
DATA+YellowPORT terminal A
DATA-GreenPORT terminal B
Pentair's colour convention again, unchanged across the range.
Pentair yellow to PORT terminal A and green to PORT terminal B, with the optional black common to G.
Yellow positive, green negative, as on every Pentair device.

The part that is specific to a hybrid

A hybrid decides internally whether to run the heat pump, the gas burner, or both, based on its own logic and conditions. A dry contact can only say heat or no heat, so under relay control the unit picks the source and the module has no say. That is usually the right outcome, since the unit is optimising for cost and recovery time, but it should be explained rather than discovered.

When it does not respond

SymptomWhere to look first
No response to anythingRemote Mode left on OFF.
Method and wiring disagreeRemote Mode set to RELAY while wired for RS-485, or the reverse.
Silent on RS-485Green and yellow swapped, or sharing a PORT with another device.
Runs the wrong heat sourceExpected under relay control — the unit chooses. Not a fault to chase in the wiring.

Sources