diff --git a/custom_components/gree_custom/aiogree/api.py b/custom_components/gree_custom/aiogree/api.py
index 498bb55..3b7ff5e 100755
--- a/custom_components/gree_custom/aiogree/api.py
+++ b/custom_components/gree_custom/aiogree/api.py
@@ -499,10 +499,12 @@ class DeviceScanInfoResponse(BaseModel):
     # Scan Responses format:
     # {"t":"dev","bc":"","catalog":"gree","series":"gree","model":"gree","lock":0,"vender":"1","mid":"60","name":"GR-Gcloud_60_0a_5ba3_EC","ver":"V3.2.M","mac":"9424b8fd5ba3","subCnt":6}
     # {'t': 'dev', 'cid': 'c03937b12280', 'bc': '00000000000000000000000000000000', 'brand': 'gree', 'catalog': 'gree', 'mac': 'c03937b12280', 'mid': '10001', 'model': 'gree', 'name': '', 'lock': 0, 'series': 'gree', 'vender': '1', 'ver': 'V3.4.M', 'ModelType': '32776', 'hid': '362001065279+U-WB05RT13V1.45.bin'}
+    # A zone controller sends no cid:
+    # {"t":"dev","bc":"gree","catalog":"gree","mid":"50","lock":0,"model":"gree","name":"GR-ZCntrlr_5000_02_ffee_EC","series":"gree","vender":"2","ver":"V1.2.1","brand":"gree","mac":"9424b8c0ffee","subCnt":5}
     model_config = ConfigDict(extra="ignore")
 
     t: str
-    cid: str
+    cid: str | None = None
     mac: str
     bc: str | None = None
     brand: str | None = None
diff --git a/docs/protocol.md b/docs/protocol.md
index d793c6a..9b3469e 100644
--- a/docs/protocol.md
+++ b/docs/protocol.md
@@ -37,6 +37,7 @@ Facts about how Gree devices behave on the wire. Most of these are not visible f
 ## Discovery and network
 
 - Local discovery is a plain text `{"t": "scan"}` UDP broadcast. The device answers with a `dev` pack encrypted with the generic key.
+- Most devices put a `cid` in that `dev` pack. Some do not (seen: a Gree LE60-13/GH zone controller), so `DeviceScanInfoResponse` must not require it. Nothing reads it.
 - `extra_scan_networks` and `extra_scan_hosts` exist for devices on another subnet, where a broadcast does not reach. Those are probed with unicast.
 - A device that does not answer the scan cannot be bound. Setup retries the scan with the normal transport retries.
 
diff --git a/tests/test_discovery_local.py b/tests/test_discovery_local.py
index 97d8222..bd69476 100644
--- a/tests/test_discovery_local.py
+++ b/tests/test_discovery_local.py
@@ -14,6 +14,7 @@
 # pytest pattern, not shadowing.
 
 from collections.abc import AsyncIterator, Callable
+from typing import Any, override
 
 from aiogree.transport_udp import GreeUdpTransport
 import pytest
@@ -58,6 +59,31 @@ async def test_one_device_answers_a_targeted_scan(
     assert found[0].host == device.host
 
 
+class FakeDeviceWithoutCid(FakeGreeDevice):
+    """A unit whose scan reply has no cid (seen: a Gree LE60-13/GH zone controller)."""
+
+    @override
+    def build_scan_info(self) -> dict[str, Any]:
+        """Answer the scan without the cid field."""
+        info = super().build_scan_info()
+        del info["cid"]
+        return info
+
+
+async def test_a_scan_reply_without_cid_is_accepted(
+    loopback_ip: str, discover_one: DiscoverOne
+) -> None:
+    """The cid is not needed for anything, so a reply without it must not fail."""
+    fake = FakeDeviceWithoutCid(name="Zone controller")
+    await fake.start(loopback_ip, DISCOVERY_PORT)
+    try:
+        found = await discover_one(fake.host, timeout=1)
+    finally:
+        fake.close()
+
+    assert [(d.mac, d.name) for d in found] == [(DEFAULT_MAC, "Zone controller")]
+
+
 async def test_a_scan_closes_the_transport_it_opened(
     device: FakeGreeDevice, discover_one: DiscoverOne, monkeypatch: pytest.MonkeyPatch
 ) -> None: