diff --git a/ontology/yaml/resources/HVAC/entity_types/ABSTRACT.yaml b/ontology/yaml/resources/HVAC/entity_types/ABSTRACT.yaml
index e6be6bc3f..e216a8309 100644
--- a/ontology/yaml/resources/HVAC/entity_types/ABSTRACT.yaml
+++ b/ontology/yaml/resources/HVAC/entity_types/ABSTRACT.yaml
@@ -3000,6 +3000,10 @@ HT2SWC:
   - heating_thermal_power_capacity
   - high_supply_water_temperature_alarm
   - low_supply_water_temperature_alarm
+  - heater_run_status_1
+  - heater_run_status_2
+  - failed_alarm_1
+  - failed_alarm_2
   uses:
   - heater_run_command_1
   - heater_run_command_2
@@ -5091,6 +5095,20 @@ SWTM:
   - supply_water_temperature_sensor
 
 
+RWTM:
+  description: "Return water temperature monitoring."
+  is_abstract: true
+  implements:
+  - MONITORING
+  opt_uses:
+  - cooling_request_count
+  - heating_request_count
+  - high_return_water_temperature_alarm
+  - low_return_water_temperature_alarm
+  uses:
+  - return_water_temperature_sensor
+
+
 CWDPM:
   guid: "d71e1e0d-35d6-4b53-a570-2e12959c951b"
   description: "Differential pressure monitoring for condenser water."
diff --git a/ontology/yaml/resources/HVAC/entity_types/BLR.yaml b/ontology/yaml/resources/HVAC/entity_types/BLR.yaml
index 2b565bab5..debf973ae 100644
--- a/ontology/yaml/resources/HVAC/entity_types/BLR.yaml
+++ b/ontology/yaml/resources/HVAC/entity_types/BLR.yaml
@@ -282,6 +282,14 @@ BLR_SS_RWTC_HTRWC:
   - RWTC
   - HTRWC
 
+BLR_HT2SWC_RWTM:
+  description: "Two-stage boiler with supply control, return temperature monitoring."
+  is_canonical: true
+  implements:
+  - BLR
+  - HT2SWC
+  - RWTM
+
 ###################################
 ### Existing Non-standard Types ###
 ###################################