FHP/Bosch Genesis VI Control Board Blink Code Guide (SX, GO Series)

Older FHP and Bosch water-source heat pumps — the SX and GO series, along with several other units of that vintage — use a Genesis VI control board to run safety lockouts and flag faults. When something trips a safety input, the board's red diagnostic LED blinks a repeating count that tells you which device tripped. Here's how to read it.

How the blink code works

The Genesis VI board monitors a set of safety switches (high pressure, low pressure, high temperature, low temperature, condensate overflow, brown-out, and compressor overload on 2-speed SX units). When one of those inputs opens the circuit, the board locks out the unit and blinks its diagnostic LED the number of times shown below, on a repeating loop, until the fault clears and the board is reset.

Genesis VI blink codes

Notes that affect diagnosis

• Every safety input is a normally-closed switch except the condensate overflow switch, which can be configured normally-open or normally-closed using the handheld programming device — worth checking if you're getting overflow faults on a unit with a dry pan.
• The low-pressure input is bypassed for the first 180 seconds after the compressor (Y1) output initiates, so the board doesn't nuisance-trip during a cold start.
• The condensate overflow input has a 270-second monitoring delay before it locks the unit out — a brief splash won't shut the system down.
• On SX-Series units, the Genesis VI board pairs with a separate SX-interface board mounted to the motherboard; the blink codes above come from the Genesis VI board itself.

If your Genesis board is failing

SX (discontinued 1997) and GO (discontinued 2003) are long out of production, and Genesis VI control boards for them are getting harder to source. If you're troubleshooting nuisance lockouts, a blinking LED with no obvious tripped switch, or a board that won't hold a reset, board failure itself is a common cause on units this age. We stock UPM I and UPM II unit protection modules — the control-board architecture that replaced Genesis-era boards on newer FHP/Bosch lines — but board generations aren't universally interchangeable across every unit in this age range, so confirm your exact model and serial number with us before ordering.

Still stuck on a fault?

Send us the blink count, the unit's model and serial number, and what you've already checked, and we'll help you narrow it down and get the right part shipped.

Frequently Asked Questions

What does the blinking LED on a Genesis VI control board mean?

It's a repeating fault count. The board monitors a set of safety switches, and when one trips, it locks out the unit and blinks its diagnostic LED a fixed number of times on a loop until the fault clears and the board is reset — 1 blink is brown-out, 2 is high pressure, 3 is low pressure, 4 is high temperature, 5 is low temperature, 6 is condensate overflow, and 7 is compressor overload on SX 2-speed units.

Which units use the Genesis VI control board?

The SX series (discontinued 1997) and GO series (discontinued 2003), along with several other FHP/Bosch units of that same vintage.

I'm getting a condensate overflow blink code but the pan is dry — why?

The condensate overflow switch is the one safety input that can be configured normally-open or normally-closed using the handheld programming device, unlike every other input on the board, which is normally-closed. Check how it's configured before assuming the switch itself has failed.

Why doesn't my unit trip a low-pressure fault right at cold start?

The low-pressure input is intentionally bypassed for the first 180 seconds after the compressor (Y1) output initiates, so the board doesn't nuisance-trip while pressures are still stabilizing.

Are Genesis VI control boards still available?

They're getting harder to source since SX and GO have been out of production since 1997 and 2003 respectively. We stock UPM I and UPM II unit protection modules, the architecture that replaced Genesis-era boards on newer FHP/Bosch lines, but board generations aren't universally interchangeable across every unit in this age range — confirm your exact model and serial number before ordering.