diff --git a/homeassistant/components/iaqualink/__init__.py b/homeassistant/components/iaqualink/__init__.py
index 61f2c906c17..73aa6f18867 100644
--- a/homeassistant/components/iaqualink/__init__.py
+++ b/homeassistant/components/iaqualink/__init__.py
@@ -6,16 +6,16 @@ from functools import wraps
 import logging
 
 import aiohttp.client_exceptions
-from iaqualink import (
+from iaqualink.client import AqualinkClient
+from iaqualink.device import (
     AqualinkBinarySensor,
-    AqualinkClient,
     AqualinkDevice,
     AqualinkLight,
-    AqualinkLoginException,
     AqualinkSensor,
     AqualinkThermostat,
     AqualinkToggle,
 )
+from iaqualink.exception import AqualinkServiceException
 import voluptuous as vol
 
 from homeassistant import config_entries
@@ -73,12 +73,12 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     """Set up the Aqualink component."""
     conf = config.get(DOMAIN)
 
-    hass.data[DOMAIN] = {}
-
     if conf is not None:
         hass.async_create_task(
             hass.config_entries.flow.async_init(
-                DOMAIN, context={"source": config_entries.SOURCE_IMPORT}, data=conf
+                DOMAIN,
+                context={"source": config_entries.SOURCE_IMPORT},
+                data=conf,
             )
         )
 
@@ -90,6 +90,8 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     username = entry.data[CONF_USERNAME]
     password = entry.data[CONF_PASSWORD]
 
+    hass.data.setdefault(DOMAIN, {})
+
     # These will contain the initialized devices
     binary_sensors = hass.data[DOMAIN][BINARY_SENSOR_DOMAIN] = []
     climates = hass.data[DOMAIN][CLIMATE_DOMAIN] = []
@@ -101,24 +103,36 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     aqualink = AqualinkClient(username, password, session)
     try:
         await aqualink.login()
-    except AqualinkLoginException as login_exception:
+    except AqualinkServiceException as login_exception:
         _LOGGER.error("Failed to login: %s", login_exception)
         return False
     except (
         asyncio.TimeoutError,
         aiohttp.client_exceptions.ClientConnectorError,
     ) as aio_exception:
-        _LOGGER.warning("Exception raised while attempting to login: %s", aio_exception)
-        raise ConfigEntryNotReady from aio_exception
+        raise ConfigEntryNotReady(
+            f"Error while attempting login: {aio_exception}"
+        ) from aio_exception
+
+    try:
+        systems = await aqualink.get_systems()
+    except AqualinkServiceException as svc_exception:
+        raise ConfigEntryNotReady(
+            f"Error while attempting to retrieve systems list: {svc_exception}"
+        ) from svc_exception
 
-    systems = await aqualink.get_systems()
     systems = list(systems.values())
     if not systems:
         _LOGGER.error("No systems detected or supported")
         return False
 
     # Only supporting the first system for now.
-    devices = await systems[0].get_devices()
+    try:
+        devices = await systems[0].get_devices()
+    except AqualinkServiceException as svc_exception:
+        raise ConfigEntryNotReady(
+            f"Error while attempting to retrieve devices list: {svc_exception}"
+        ) from svc_exception
 
     for dev in devices.values():
         if isinstance(dev, AqualinkThermostat):
@@ -151,15 +165,17 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 
     async def _async_systems_update(now):
         """Refresh internal state for all systems."""
-        prev = systems[0].last_run_success
+        prev = systems[0].online
 
-        await systems[0].update()
-        success = systems[0].last_run_success
-
-        if not success and prev:
-            _LOGGER.warning("Failed to refresh iAqualink state")
-        elif success and not prev:
-            _LOGGER.warning("Reconnected to iAqualink")
+        try:
+            await systems[0].update()
+        except AqualinkServiceException as svc_exception:
+            if prev is not None:
+                _LOGGER.warning("Failed to refresh iAqualink state: %s", svc_exception)
+        else:
+            cur = systems[0].online
+            if cur is True and prev is not True:
+                _LOGGER.warning("Reconnected to iAqualink")
 
         async_dispatcher_send(hass, DOMAIN)
 
@@ -174,7 +190,7 @@ async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         platform for platform in PLATFORMS if platform in hass.data[DOMAIN]
     ]
 
-    hass.data[DOMAIN].clear()
+    del hass.data[DOMAIN]
 
     return await hass.config_entries.async_unload_platforms(entry, platforms_to_unload)
 
@@ -228,12 +244,12 @@ class AqualinkEntity(Entity):
     @property
     def assumed_state(self) -> bool:
         """Return whether the state is based on actual reading from the device."""
-        return not self.dev.system.last_run_success
+        return self.dev.system.online in [False, None]
 
     @property
     def available(self) -> bool:
         """Return whether the device is available or not."""
-        return self.dev.system.online
+        return self.dev.system.online is True
 
     @property
     def device_info(self) -> DeviceInfo:
diff --git a/homeassistant/components/iaqualink/climate.py b/homeassistant/components/iaqualink/climate.py
index 13245429c0a..2986bea2dc7 100644
--- a/homeassistant/components/iaqualink/climate.py
+++ b/homeassistant/components/iaqualink/climate.py
@@ -3,13 +3,13 @@ from __future__ import annotations
 
 import logging
 
-from iaqualink import AqualinkHeater, AqualinkPump, AqualinkSensor, AqualinkState
 from iaqualink.const import (
     AQUALINK_TEMP_CELSIUS_HIGH,
     AQUALINK_TEMP_CELSIUS_LOW,
     AQUALINK_TEMP_FAHRENHEIT_HIGH,
     AQUALINK_TEMP_FAHRENHEIT_LOW,
 )
+from iaqualink.device import AqualinkHeater, AqualinkPump, AqualinkSensor, AqualinkState
 
 from homeassistant.components.climate import ClimateEntity
 from homeassistant.components.climate.const import (
@@ -24,6 +24,7 @@ from homeassistant.core import HomeAssistant
 
 from . import AqualinkEntity, refresh_system
 from .const import CLIMATE_SUPPORTED_MODES, DOMAIN as AQUALINK_DOMAIN
+from .utils import await_or_reraise
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -76,9 +77,9 @@ class HassAqualinkThermostat(AqualinkEntity, ClimateEntity):
     async def async_set_hvac_mode(self, hvac_mode: str) -> None:
         """Turn the underlying heater switch on or off."""
         if hvac_mode == HVAC_MODE_HEAT:
-            await self.heater.turn_on()
+            await await_or_reraise(self.heater.turn_on())
         elif hvac_mode == HVAC_MODE_OFF:
-            await self.heater.turn_off()
+            await await_or_reraise(self.heater.turn_off())
         else:
             _LOGGER.warning("Unknown operation mode: %s", hvac_mode)
 
@@ -111,7 +112,7 @@ class HassAqualinkThermostat(AqualinkEntity, ClimateEntity):
     @refresh_system
     async def async_set_temperature(self, **kwargs) -> None:
         """Set new target temperature."""
-        await self.dev.set_temperature(int(kwargs[ATTR_TEMPERATURE]))
+        await await_or_reraise(self.dev.set_temperature(int(kwargs[ATTR_TEMPERATURE])))
 
     @property
     def sensor(self) -> AqualinkSensor:
diff --git a/homeassistant/components/iaqualink/config_flow.py b/homeassistant/components/iaqualink/config_flow.py
index 5380a97901e..a91964ba3bc 100644
--- a/homeassistant/components/iaqualink/config_flow.py
+++ b/homeassistant/components/iaqualink/config_flow.py
@@ -3,7 +3,11 @@ from __future__ import annotations
 
 from typing import Any
 
-from iaqualink import AqualinkClient, AqualinkLoginException
+from iaqualink.client import AqualinkClient
+from iaqualink.exception import (
+    AqualinkServiceException,
+    AqualinkServiceUnauthorizedException,
+)
 import voluptuous as vol
 
 from homeassistant import config_entries
@@ -32,16 +36,22 @@ class AqualinkFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
             password = user_input[CONF_PASSWORD]
 
             try:
-                aqualink = AqualinkClient(username, password)
-                await aqualink.login()
-                return self.async_create_entry(title=username, data=user_input)
-            except AqualinkLoginException:
+                async with AqualinkClient(username, password):
+                    pass
+            except AqualinkServiceUnauthorizedException:
+                errors["base"] = "invalid_auth"
+            except AqualinkServiceException:
                 errors["base"] = "cannot_connect"
+            else:
+                return self.async_create_entry(title=username, data=user_input)
 
         return self.async_show_form(
             step_id="user",
             data_schema=vol.Schema(
-                {vol.Required(CONF_USERNAME): str, vol.Required(CONF_PASSWORD): str}
+                {
+                    vol.Required(CONF_USERNAME): str,
+                    vol.Required(CONF_PASSWORD): str,
+                }
             ),
             errors=errors,
         )
diff --git a/homeassistant/components/iaqualink/light.py b/homeassistant/components/iaqualink/light.py
index 17b686947ce..9cc5f5c2194 100644
--- a/homeassistant/components/iaqualink/light.py
+++ b/homeassistant/components/iaqualink/light.py
@@ -1,5 +1,5 @@
 """Support for Aqualink pool lights."""
-from iaqualink import AqualinkLightEffect
+import logging
 
 from homeassistant.components.light import (
     ATTR_BRIGHTNESS,
@@ -14,6 +14,9 @@ from homeassistant.core import HomeAssistant
 
 from . import AqualinkEntity, refresh_system
 from .const import DOMAIN as AQUALINK_DOMAIN
+from .utils import await_or_reraise
+
+_LOGGER = logging.getLogger(__name__)
 
 PARALLEL_UPDATES = 0
 
@@ -49,20 +52,19 @@ class HassAqualinkLight(AqualinkEntity, LightEntity):
         them.
         """
         # For now I'm assuming lights support either effects or brightness.
-        if effect := kwargs.get(ATTR_EFFECT):
-            effect = AqualinkLightEffect[effect].value
-            await self.dev.set_effect(effect)
+        if effect_name := kwargs.get(ATTR_EFFECT):
+            await await_or_reraise(self.dev.set_effect_by_name(effect_name))
         elif brightness := kwargs.get(ATTR_BRIGHTNESS):
             # Aqualink supports percentages in 25% increments.
             pct = int(round(brightness * 4.0 / 255)) * 25
-            await self.dev.set_brightness(pct)
+            await await_or_reraise(self.dev.set_brightness(pct))
         else:
-            await self.dev.turn_on()
+            await await_or_reraise(self.dev.turn_on())
 
     @refresh_system
     async def async_turn_off(self, **kwargs) -> None:
         """Turn off the light."""
-        await self.dev.turn_off()
+        await await_or_reraise(self.dev.turn_off())
 
     @property
     def brightness(self) -> int:
@@ -75,12 +77,12 @@ class HassAqualinkLight(AqualinkEntity, LightEntity):
     @property
     def effect(self) -> str:
         """Return the current light effect if supported."""
-        return AqualinkLightEffect(self.dev.effect).name
+        return self.dev.effect
 
     @property
     def effect_list(self) -> list:
         """Return supported light effects."""
-        return list(AqualinkLightEffect.__members__)
+        return list(self.dev.supported_light_effects)
 
     @property
     def supported_features(self) -> int:
diff --git a/homeassistant/components/iaqualink/manifest.json b/homeassistant/components/iaqualink/manifest.json
index 26c6e0b4bfd..8061163943d 100644
--- a/homeassistant/components/iaqualink/manifest.json
+++ b/homeassistant/components/iaqualink/manifest.json
@@ -4,6 +4,6 @@
   "config_flow": true,
   "documentation": "https://www.home-assistant.io/integrations/iaqualink/",
   "codeowners": ["@flz"],
-  "requirements": ["iaqualink==0.3.90"],
+  "requirements": ["iaqualink==0.4.1"],
   "iot_class": "cloud_polling"
 }
diff --git a/homeassistant/components/iaqualink/strings.json b/homeassistant/components/iaqualink/strings.json
index 5e7fcf6aa7a..85b49996f51 100644
--- a/homeassistant/components/iaqualink/strings.json
+++ b/homeassistant/components/iaqualink/strings.json
@@ -11,7 +11,8 @@
       }
     },
     "error": {
-      "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]"
+      "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]",
+      "invalid_auth": "[%key:common::config_flow::error::invalid_auth%]"
     },
     "abort": {
       "single_instance_allowed": "[%key:common::config_flow::abort::single_instance_allowed%]"
diff --git a/homeassistant/components/iaqualink/switch.py b/homeassistant/components/iaqualink/switch.py
index a9fde150af3..fffd03add1a 100644
--- a/homeassistant/components/iaqualink/switch.py
+++ b/homeassistant/components/iaqualink/switch.py
@@ -5,6 +5,7 @@ from homeassistant.core import HomeAssistant
 
 from . import AqualinkEntity, refresh_system
 from .const import DOMAIN as AQUALINK_DOMAIN
+from .utils import await_or_reraise
 
 PARALLEL_UPDATES = 0
 
@@ -47,9 +48,9 @@ class HassAqualinkSwitch(AqualinkEntity, SwitchEntity):
     @refresh_system
     async def async_turn_on(self, **kwargs) -> None:
         """Turn on the switch."""
-        await self.dev.turn_on()
+        await await_or_reraise(self.dev.turn_on())
 
     @refresh_system
     async def async_turn_off(self, **kwargs) -> None:
         """Turn off the switch."""
-        await self.dev.turn_off()
+        await await_or_reraise(self.dev.turn_off())
diff --git a/homeassistant/components/iaqualink/utils.py b/homeassistant/components/iaqualink/utils.py
new file mode 100644
index 00000000000..b047af5869c
--- /dev/null
+++ b/homeassistant/components/iaqualink/utils.py
@@ -0,0 +1,16 @@
+"""Utility functions for Aqualink devices."""
+from __future__ import annotations
+
+from collections.abc import Awaitable
+
+from iaqualink.exception import AqualinkServiceException
+
+from homeassistant.exceptions import HomeAssistantError
+
+
+async def await_or_reraise(awaitable: Awaitable) -> None:
+    """Execute API call while catching service exceptions."""
+    try:
+        await awaitable
+    except AqualinkServiceException as svc_exception:
+        raise HomeAssistantError(f"Aqualink error: {svc_exception}") from svc_exception
diff --git a/requirements_all.txt b/requirements_all.txt
index c7f3650e4c6..49acf2268e8 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -869,7 +869,7 @@ hyperion-py==0.7.4
 iammeter==0.1.7
 
 # homeassistant.components.iaqualink
-iaqualink==0.3.90
+iaqualink==0.4.1
 
 # homeassistant.components.watson_tts
 ibm-watson==5.2.2
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 7abff39ae50..8fc576d3430 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -550,7 +550,7 @@ huisbaasje-client==0.1.0
 hyperion-py==0.7.4
 
 # homeassistant.components.iaqualink
-iaqualink==0.3.90
+iaqualink==0.4.1
 
 # homeassistant.components.ping
 icmplib==3.0
diff --git a/tests/components/iaqualink/conftest.py b/tests/components/iaqualink/conftest.py
new file mode 100644
index 00000000000..01fc78691b3
--- /dev/null
+++ b/tests/components/iaqualink/conftest.py
@@ -0,0 +1,82 @@
+"""Configuration for iAqualink tests."""
+import random
+from unittest.mock import AsyncMock
+
+from iaqualink.client import AqualinkClient
+from iaqualink.device import AqualinkDevice
+from iaqualink.system import AqualinkSystem
+import pytest
+
+from homeassistant.components.iaqualink import DOMAIN
+from homeassistant.const import CONF_PASSWORD, CONF_USERNAME
+
+from tests.common import MockConfigEntry
+
+MOCK_USERNAME = "test@example.com"
+MOCK_PASSWORD = "password"
+MOCK_DATA = {CONF_USERNAME: MOCK_USERNAME, CONF_PASSWORD: MOCK_PASSWORD}
+
+
+def async_returns(x):
+    """Return value-returning async mock."""
+    return AsyncMock(return_value=x)
+
+
+def async_raises(x):
+    """Return exception-raising async mock."""
+    return AsyncMock(side_effect=x)
+
+
+@pytest.fixture(name="client")
+def client_fixture():
+    """Create client fixture."""
+    return AqualinkClient(username=MOCK_USERNAME, password=MOCK_PASSWORD)
+
+
+def get_aqualink_system(aqualink, cls=None, data=None):
+    """Create aqualink system."""
+    if cls is None:
+        cls = AqualinkSystem
+
+    if data is None:
+        data = {}
+
+    num = random.randint(0, 99999)
+    data["serial_number"] = f"SN{num:05}"
+
+    return cls(aqualink=aqualink, data=data)
+
+
+def get_aqualink_device(system, cls=None, data=None):
+    """Create aqualink device."""
+    if cls is None:
+        cls = AqualinkDevice
+
+    if data is None:
+        data = {}
+
+    num = random.randint(0, 999)
+    data["name"] = f"name_{num:03}"
+
+    return cls(system=system, data=data)
+
+
+@pytest.fixture(name="config_data")
+def config_data_fixture():
+    """Create hass config fixture."""
+    return MOCK_DATA
+
+
+@pytest.fixture(name="config")
+def config_fixture():
+    """Create hass config fixture."""
+    return {DOMAIN: MOCK_DATA}
+
+
+@pytest.fixture(name="config_entry")
+def config_entry_fixture():
+    """Create a mock HEOS config entry."""
+    return MockConfigEntry(
+        domain=DOMAIN,
+        data=MOCK_DATA,
+    )
diff --git a/tests/components/iaqualink/test_config_flow.py b/tests/components/iaqualink/test_config_flow.py
index 38dd2ec1a3a..2d00284775d 100644
--- a/tests/components/iaqualink/test_config_flow.py
+++ b/tests/components/iaqualink/test_config_flow.py
@@ -1,20 +1,19 @@
 """Tests for iAqualink config flow."""
 from unittest.mock import patch
 
-import iaqualink
+from iaqualink.exception import (
+    AqualinkServiceException,
+    AqualinkServiceUnauthorizedException,
+)
 import pytest
 
 from homeassistant.components.iaqualink import config_flow
 
-from tests.common import MockConfigEntry, mock_coro
-
-DATA = {"username": "test@example.com", "password": "pass"}
-
 
 @pytest.mark.parametrize("step", ["import", "user"])
-async def test_already_configured(hass, step):
+async def test_already_configured(hass, config_entry, config_data, step):
     """Test config flow when iaqualink component is already setup."""
-    MockConfigEntry(domain="iaqualink", data=DATA).add_to_hass(hass)
+    config_entry.add_to_hass(hass)
 
     flow = config_flow.AqualinkFlowHandler()
     flow.hass = hass
@@ -22,14 +21,14 @@ async def test_already_configured(hass, step):
 
     fname = f"async_step_{step}"
     func = getattr(flow, fname)
-    result = await func(DATA)
+    result = await func(config_data)
 
     assert result["type"] == "abort"
 
 
 @pytest.mark.parametrize("step", ["import", "user"])
 async def test_without_config(hass, step):
-    """Test with no configuration."""
+    """Test config flow with no configuration."""
     flow = config_flow.AqualinkFlowHandler()
     flow.hass = hass
     flow.context = {}
@@ -44,7 +43,7 @@ async def test_without_config(hass, step):
 
 
 @pytest.mark.parametrize("step", ["import", "user"])
-async def test_with_invalid_credentials(hass, step):
+async def test_with_invalid_credentials(hass, config_data, step):
     """Test config flow with invalid username and/or password."""
     flow = config_flow.AqualinkFlowHandler()
     flow.hass = hass
@@ -52,9 +51,29 @@ async def test_with_invalid_credentials(hass, step):
     fname = f"async_step_{step}"
     func = getattr(flow, fname)
     with patch(
-        "iaqualink.AqualinkClient.login", side_effect=iaqualink.AqualinkLoginException
+        "homeassistant.components.iaqualink.config_flow.AqualinkClient.login",
+        side_effect=AqualinkServiceUnauthorizedException,
     ):
-        result = await func(DATA)
+        result = await func(config_data)
+
+    assert result["type"] == "form"
+    assert result["step_id"] == "user"
+    assert result["errors"] == {"base": "invalid_auth"}
+
+
+@pytest.mark.parametrize("step", ["import", "user"])
+async def test_service_exception(hass, config_data, step):
+    """Test config flow encountering service exception."""
+    flow = config_flow.AqualinkFlowHandler()
+    flow.hass = hass
+
+    fname = f"async_step_{step}"
+    func = getattr(flow, fname)
+    with patch(
+        "homeassistant.components.iaqualink.config_flow.AqualinkClient.login",
+        side_effect=AqualinkServiceException,
+    ):
+        result = await func(config_data)
 
     assert result["type"] == "form"
     assert result["step_id"] == "user"
@@ -62,17 +81,20 @@ async def test_with_invalid_credentials(hass, step):
 
 
 @pytest.mark.parametrize("step", ["import", "user"])
-async def test_with_existing_config(hass, step):
-    """Test with existing configuration."""
+async def test_with_existing_config(hass, config_data, step):
+    """Test config flow with existing configuration."""
     flow = config_flow.AqualinkFlowHandler()
     flow.hass = hass
     flow.context = {}
 
     fname = f"async_step_{step}"
     func = getattr(flow, fname)
-    with patch("iaqualink.AqualinkClient.login", return_value=mock_coro(None)):
-        result = await func(DATA)
+    with patch(
+        "homeassistant.components.iaqualink.config_flow.AqualinkClient.login",
+        return_value=None,
+    ):
+        result = await func(config_data)
 
     assert result["type"] == "create_entry"
-    assert result["title"] == DATA["username"]
-    assert result["data"] == DATA
+    assert result["title"] == config_data["username"]
+    assert result["data"] == config_data
diff --git a/tests/components/iaqualink/test_init.py b/tests/components/iaqualink/test_init.py
new file mode 100644
index 00000000000..ea7dad86908
--- /dev/null
+++ b/tests/components/iaqualink/test_init.py
@@ -0,0 +1,341 @@
+"""Tests for iAqualink integration."""
+
+import asyncio
+import logging
+from unittest.mock import AsyncMock, patch
+
+from iaqualink.device import (
+    AqualinkAuxToggle,
+    AqualinkBinarySensor,
+    AqualinkDevice,
+    AqualinkLightToggle,
+    AqualinkSensor,
+    AqualinkThermostat,
+)
+from iaqualink.exception import AqualinkServiceException
+
+from homeassistant.components.binary_sensor import DOMAIN as BINARY_SENSOR_DOMAIN
+from homeassistant.components.climate import DOMAIN as CLIMATE_DOMAIN
+from homeassistant.components.iaqualink.const import UPDATE_INTERVAL
+from homeassistant.components.light import DOMAIN as LIGHT_DOMAIN
+from homeassistant.components.sensor import DOMAIN as SENSOR_DOMAIN
+from homeassistant.components.switch import DOMAIN as SWITCH_DOMAIN
+from homeassistant.config_entries import ConfigEntryState
+from homeassistant.const import ATTR_ASSUMED_STATE, STATE_ON, STATE_UNAVAILABLE
+from homeassistant.util import dt as dt_util
+
+from tests.common import async_fire_time_changed
+from tests.components.iaqualink.conftest import get_aqualink_device, get_aqualink_system
+
+
+async def _ffwd_next_update_interval(hass):
+    now = dt_util.utcnow()
+    async_fire_time_changed(hass, now + UPDATE_INTERVAL)
+    await hass.async_block_till_done()
+
+
+async def test_setup_login_exception(hass, config_entry):
+    """Test setup encountering a login exception."""
+    config_entry.add_to_hass(hass)
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login",
+        side_effect=AqualinkServiceException,
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.SETUP_ERROR
+
+
+async def test_setup_login_timeout(hass, config_entry):
+    """Test setup encountering a timeout while logging in."""
+    config_entry.add_to_hass(hass)
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login",
+        side_effect=asyncio.TimeoutError,
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.SETUP_RETRY
+
+
+async def test_setup_systems_exception(hass, config_entry):
+    """Test setup encountering an exception while retrieving systems."""
+    config_entry.add_to_hass(hass)
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        side_effect=AqualinkServiceException,
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.SETUP_RETRY
+
+
+async def test_setup_no_systems_recognized(hass, config_entry):
+    """Test setup ending in no systems recognized."""
+    config_entry.add_to_hass(hass)
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        return_value={},
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.SETUP_ERROR
+
+
+async def test_setup_devices_exception(hass, config_entry, client):
+    """Test setup encountering an exception while retrieving devices."""
+    config_entry.add_to_hass(hass)
+
+    system = get_aqualink_system(client)
+    systems = {system.serial: system}
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        return_value=systems,
+    ), patch.object(
+        system, "get_devices"
+    ) as mock_get_devices:
+        mock_get_devices.side_effect = AqualinkServiceException
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.SETUP_RETRY
+
+
+async def test_setup_all_good_no_recognized_devices(hass, config_entry, client):
+    """Test setup ending in no devices recognized."""
+    config_entry.add_to_hass(hass)
+
+    system = get_aqualink_system(client)
+    systems = {system.serial: system}
+
+    device = get_aqualink_device(system, AqualinkDevice)
+    devices = {device.name: device}
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        return_value=systems,
+    ), patch.object(
+        system, "get_devices"
+    ) as mock_get_devices:
+        mock_get_devices.return_value = devices
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.LOADED
+
+    assert len(hass.states.async_entity_ids(BINARY_SENSOR_DOMAIN)) == 0
+    assert len(hass.states.async_entity_ids(CLIMATE_DOMAIN)) == 0
+    assert len(hass.states.async_entity_ids(LIGHT_DOMAIN)) == 0
+    assert len(hass.states.async_entity_ids(SENSOR_DOMAIN)) == 0
+    assert len(hass.states.async_entity_ids(SWITCH_DOMAIN)) == 0
+
+    assert await hass.config_entries.async_unload(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.NOT_LOADED
+
+
+async def test_setup_all_good_all_device_types(hass, config_entry, client):
+    """Test setup ending in one device of each type recognized."""
+    config_entry.add_to_hass(hass)
+
+    system = get_aqualink_system(client)
+    systems = {system.serial: system}
+
+    devices = [
+        get_aqualink_device(system, AqualinkAuxToggle),
+        get_aqualink_device(system, AqualinkBinarySensor),
+        get_aqualink_device(system, AqualinkLightToggle),
+        get_aqualink_device(system, AqualinkSensor),
+        get_aqualink_device(system, AqualinkThermostat),
+    ]
+    devices = {d.name: d for d in devices}
+
+    system.get_devices = AsyncMock(return_value=devices)
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        return_value=systems,
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.LOADED
+
+    assert len(hass.states.async_entity_ids(BINARY_SENSOR_DOMAIN)) == 1
+    assert len(hass.states.async_entity_ids(CLIMATE_DOMAIN)) == 1
+    assert len(hass.states.async_entity_ids(LIGHT_DOMAIN)) == 1
+    assert len(hass.states.async_entity_ids(SENSOR_DOMAIN)) == 1
+    assert len(hass.states.async_entity_ids(SWITCH_DOMAIN)) == 1
+
+    assert await hass.config_entries.async_unload(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.NOT_LOADED
+
+
+async def test_multiple_updates(hass, config_entry, caplog, client):
+    """Test all possible results of online status transition after update."""
+    config_entry.add_to_hass(hass)
+
+    system = get_aqualink_system(client)
+    systems = {system.serial: system}
+
+    system.get_devices = AsyncMock(return_value={})
+
+    caplog.set_level(logging.WARNING)
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        return_value=systems,
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.LOADED
+
+    def set_online_to_true():
+        system.online = True
+
+    def set_online_to_false():
+        system.online = False
+
+    system.update = AsyncMock()
+
+    # True -> True
+    system.online = True
+    caplog.clear()
+    system.update.side_effect = set_online_to_true
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 0
+
+    # True -> False
+    system.online = True
+    caplog.clear()
+    system.update.side_effect = set_online_to_false
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 0
+
+    # True -> None / ServiceException
+    system.online = True
+    caplog.clear()
+    system.update.side_effect = AqualinkServiceException
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 1
+    assert "Failed" in caplog.text
+
+    # False -> False
+    system.online = False
+    caplog.clear()
+    system.update.side_effect = set_online_to_false
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 0
+
+    # False -> True
+    system.online = False
+    caplog.clear()
+    system.update.side_effect = set_online_to_true
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 1
+    assert "Reconnected" in caplog.text
+
+    # False -> None / ServiceException
+    system.online = False
+    caplog.clear()
+    system.update.side_effect = AqualinkServiceException
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 1
+    assert "Failed" in caplog.text
+
+    # None -> None / ServiceException
+    system.online = None
+    caplog.clear()
+    system.update.side_effect = AqualinkServiceException
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 0
+
+    # None -> True
+    system.online = None
+    caplog.clear()
+    system.update.side_effect = set_online_to_true
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 1
+    assert "Reconnected" in caplog.text
+
+    # None -> False
+    system.online = None
+    caplog.clear()
+    system.update.side_effect = set_online_to_false
+    await _ffwd_next_update_interval(hass)
+    assert len(caplog.records) == 0
+
+    assert await hass.config_entries.async_unload(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    assert config_entry.state is ConfigEntryState.NOT_LOADED
+
+
+async def test_entity_assumed_and_available(hass, config_entry, client):
+    """Test assumed_state and_available properties for all values of online."""
+    config_entry.add_to_hass(hass)
+
+    system = get_aqualink_system(client)
+    systems = {system.serial: system}
+
+    light = get_aqualink_device(system, AqualinkLightToggle, data={"state": "1"})
+    devices = {d.name: d for d in [light]}
+    system.get_devices = AsyncMock(return_value=devices)
+    system.update = AsyncMock()
+
+    with patch(
+        "homeassistant.components.iaqualink.AqualinkClient.login", return_value=None
+    ), patch(
+        "homeassistant.components.iaqualink.AqualinkClient.get_systems",
+        return_value=systems,
+    ):
+        await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert len(hass.states.async_entity_ids(LIGHT_DOMAIN)) == 1
+
+    name = f"{LIGHT_DOMAIN}.{light.name}"
+
+    # None means maybe.
+    light.system.online = None
+    await _ffwd_next_update_interval(hass)
+    state = hass.states.get(name)
+    assert state.state == STATE_UNAVAILABLE
+    assert state.attributes.get(ATTR_ASSUMED_STATE) is True
+
+    light.system.online = False
+    await _ffwd_next_update_interval(hass)
+    state = hass.states.get(name)
+    assert state.state == STATE_UNAVAILABLE
+    assert state.attributes.get(ATTR_ASSUMED_STATE) is True
+
+    light.system.online = True
+    await _ffwd_next_update_interval(hass)
+    state = hass.states.get(name)
+    assert state.state == STATE_ON
+    assert state.attributes.get(ATTR_ASSUMED_STATE) is None
diff --git a/tests/components/iaqualink/test_utils.py b/tests/components/iaqualink/test_utils.py
new file mode 100644
index 00000000000..56b239c0d9f
--- /dev/null
+++ b/tests/components/iaqualink/test_utils.py
@@ -0,0 +1,23 @@
+"""Tests for iAqualink integration utility functions."""
+
+from iaqualink.exception import AqualinkServiceException
+import pytest
+
+from homeassistant.components.iaqualink.utils import await_or_reraise
+from homeassistant.exceptions import HomeAssistantError
+
+from tests.components.iaqualink.conftest import async_raises, async_returns
+
+
+async def test_await_or_reraise(hass):
+    """Test await_or_reraise for all values of awaitable."""
+    async_noop = async_returns(None)
+    await await_or_reraise(async_noop())
+
+    with pytest.raises(Exception):
+        async_ex = async_raises(Exception)
+        await await_or_reraise(async_ex())
+
+    with pytest.raises(HomeAssistantError):
+        async_ex = async_raises(AqualinkServiceException)
+        await await_or_reraise(async_ex())