diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 0e8b45397..5c15917c4 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -6642,6 +6642,11 @@ def _pashub_cylinder_size_code(
 _PASHUB_SECONDARY_HEATING_TYPE_TO_SAP10: Dict[str, int] = {
     # Electric direct-acting (eff 1.00) — modal cohort heater.
     "Panel, convector or radiant heaters": 691,
+    # Electric water/oil-filled radiators (PCDB 694, eff 1.00). Unhyphenated —
+    # the secondary-heating survey field lodges its own spelling, distinct from
+    # the hyphenated `_PASHUB_ROOM_HEATER_TYPE_TO_SAP10` main-heating label;
+    # both entries are legitimately separate, do not alias.
+    "Water or oil filled radiators": 694,
     # Gas room heaters (Table 4a column A).
     "Flush fitting live fuel effect open front fire, sealed to fireplace": 605,
     "1980 or later - Open front fire with open flue, sealed to fireplace": 603,