External Filter Coordination

Solve the E90 flow error by coordinating your Steinbach filter with spa heating.

The Problem

Your Steinbach Comfort 50 external filter connects via Y-connector and diverts water from the original Intex pump. The flow switch detects reduced flow and triggers E90 (low water flow) error.

Solution: Smart Coordination

Don't run both systems simultaneously during heating. Use Home Assistant automations to:

Stop external filter when spa heater activates
Schedule external filtration during heating idle periods
Pre-heat before scheduled use times, then run external filter

Setup Requirements

Smart Plug for Steinbach

Put your Steinbach Comfort 50 on a WiFi smart plug (Tasmota, Shelly, etc.) so Home Assistant can control it.

Home Assistant

Both the spa controller and smart plug need to be in HA to create coordination automations.

Automation: Stop External Filter When Heating

automation:
  - alias: "Spa - Stop External Filter When Heating"
    trigger:
      - platform: state
        entity_id: switch.intex_spa_heater
        to: "on"
    action:
      - service: switch.turn_off
        entity_id: switch.steinbach_filter

Automation: Schedule External Filter

automation:
  - alias: "Spa - External Filter Schedule"
    trigger:
      - platform: time_pattern
        hours: "/4"  # Every 4 hours
    condition:
      - condition: state
        entity_id: switch.intex_spa_heater
        state: "off"
      # Only run if spa is heating idle
      - condition: template
        value_template: >
          {{ state_attr('climate.intex_spa_water_temperature', 'hvac_action') == 'idle' }}
    action:
      - service: switch.turn_on
        entity_id: switch.steinbach_filter
      - delay: "01:00:00"  # Run for 1 hour
      - service: switch.turn_off
        entity_id: switch.steinbach_filter

Automation: Pre-Heat Before Use

automation:
  - alias: "Spa - Pre-Heat for Evening Use"
    trigger:
      - platform: time
        at: "16:00:00"  # Start heating at 4 PM
    condition:
      - condition: time
        weekday: [fri, sat, sun]  # Weekend only
    action:
      # Stop external filter
      - service: switch.turn_off
        entity_id: switch.steinbach_filter
      # Set target temperature
      - service: climate.set_temperature
        entity_id: climate.intex_spa_water_temperature
        data:
          temperature: 38
      # Turn on heater
      - service: switch.turn_on
        entity_id: switch.intex_spa_heater

Alternative: Flow Bypass Relay

Hardware Bypass (Advanced)

If software coordination isn't enough, you can add a relay to bypass the flow switch when the external filter is running. This requires modifying the Intex mainboard and voids warranty.

Flow Switch ──┬── Normal path ──┬── To mainboard
              │                 │
              └── Relay (NO) ───┘
                    │
              GPIO from Pico W (via optocoupler)

Warning: This disables flow protection while the relay is active. Only use if you fully understand the safety implications.

Recommended Approach

Start with software

Try the coordination automations first

Adjust Y-connector

Tune valve positions for minimum flow impact

Bypass as last resort

Only if software coordination fails