Issue
The Drayton Theta YBL3 Valve Body / Actuator assembly is to be replaced.
Environment
- Replacement
- Drayton
- Actuator
- Valve
- YBL3
Cause
The Drayton Theta YBL3 Valve Body / Actuator assembly is obsolete.
Resolution
OVERVIEW
The Drayton Theta YBL3 Valve Body / Actuator assembly is obsolete, and there is no purpose built replacement.
The Valve Body was available in 1.1/4", 1.1/2" and 2" B.S.P. sizes and was normally installed as a mixing valve in variable temperature, constant volume, compensated heating circuits.
No Valve Body / Actuator assemblies are currently available in these sizes.
Details of the YB Valve Body may be viewed here.
VALVE BODY REPLACEMENT
To replace the YBL3 Valve Body the following is required:-
S-E Satchwell MB Valve Body of appropriate size - MB1552 (1.1/4"), MB1602 (1.1/2"), MB1652 (2")
Details of the MB Valve Body may be viewed here.
ACTUATOR REPLACEMENT (6-WIRE INSTALLATION)
The YBL3 Actuator normally comprised a 6-wire electrical connection enabling it to be operated by a Theta Potentiometric Controller as follows :-
Terminal M1 – Open signal
Terminal M2 – Close signal
Terminal M3 – Common
Terminal M4 – 135 ohm Feedback Potentiometer – winding
Terminal M5 – 135 ohm Feedback Potentiometer – wiper
Terminal M6 – 135 ohm Feedback Potentiometer – winding
Where 6 wires are connected to the YBL3 Actuator then the Actuator may be replaced by one or other of the following S-E Actuators :-
MD10B-24
MD20B-24 (if MD10B-24 not available)
Details of the MD10B-24 Actuator may be viewed here
Details of the MD20B-24 Actuator may be viewed here.
N.B.
The YBL3 Actuator may also have included an additional 2-wire electrical connection associated with integral Transfer Switches wired as follows :-
Terminal M7 – M1 made to M7 when YBL3 Fully Closed (24Vac)
Terminal M8 – M2 made to M8 when YBL3 Fully Open (24Vac)
Where external wiring is connected to YBL3 Transfer Switch Terminals M7 or M8 then an Auxiliary Switch Kit containing two S.P.C.O. Auxiliary Switches should be installed on the MD Actuator.
Auxiliary Switch Kit MD-S2 (914-1061-000)
Details of the MD-S2 Auxiliary Switch Kit may be viewed here.
Where external wiring is connected to YBL3 Terminal M7 then the MD-S2 Auxiliary Switch Kit should be wired as follows :-
Terminal S1 (Common) - connect to 24Vac power source
Terminal S2 (Normally Closed) - connect to 24Vac device previously connected to YBL3 Terminal M7
Terminal S3 (Normally Open) - no connection necessary
Where external wiring is connected to YBL3 Terminal M8 then the MD-S2 Auxiliary Switch Kit should be wired as follows :-
Terminal S4 (Common) - connect to independent 24Vac supply
Terminal S5 (Normally Closed) - no connection necessary
Terminal S6 (Normally Open) - connect to 24Vac device previously connected to YBL3 Terminal M8
LINKAGE KIT
A Linkage Kit will also be required in order to enable the MD Actuator to be mounted on the MB Valve Body.
Linkage Kit LMD/AR-MB (914-1071-000)
Details of the LMD/AR-MB Linkage Kit may be viewed here
IMPORTANT NOTE
In such 6-wire installations not only will the YBL3 Valve / Actuator assembly need to be replaced but the associated Theta Potentiometric Controller and its Sensors will also need to be replaced.
CONTROLLER REPLACEMENT
The Theta Potentiometric Controller may be replaced by the S-E Satchwell CSC5252 or the CSC5352 Compensator Controller.
Details of the CSC Controllers may be viewed here.
SENSOR REPLACEMENT
Theta 3-wire Temperature Sensors may be replaced by S-E Satchwell 2-wire Temperature Sensors compatible with the S-E Satchwell CSC 5252 or CSC5352 Compensator Controllers selected from the following as appropriate.
Outside Air Temperature Sensor (STO 600)
Contact Temperature Sensor (STC 600), or alternatively :-
Immersion Temperature Sensor (STP 660) + Sensor Pocket Adaptor (DWA 0001)
Room Temperature Sensor (STR 600) – OPTIONAL ONLY
Details of the STO 600 Outside Air Temperature Sensor may be viewed here
Details of the STC 600 Contact Temperature Sensor may be viewed here.
Details of the STP 660 Water Temperature Sensor may be viewed here.
Details of the DWA 0001 Sensor Pocket Adaptor may be viewed here.
Details of the STR 600 Room Temperature Sensor may be viewed here.
ACTUATOR REPLACEMENT (3-WIRE INSTALLATION)
Should only 3 wires be connected to a YBL3 Actuator then the Actuator may be replaced by one or other of the following S-E Actuators :-
MD10B-24
MD20B-24 (if MD10B-24 not available)
Details of the MD10B-24 Actuator may be viewed here.
Details of the MD20B-24 Actuator may be viewed here.
N.B.
The YBL3 Actuator may also have included an additional 2-wire electrical connection associated with integral Transfer Switches wired as follows :-
Terminal M7 – M1 made to M7 when YBL3 Fully Closed (24Vac)
Terminal M8 – M2 made to M8 when YBL3 Fully Open (24Vac)
Where external wiring is connected to YBL3 Transfer Switch Terminals M7 or M8 then an Auxiliary Switch Kit containing two S.P.C.O. Auxiliary Switches should be installed on the MD Actuator.
Auxiliary Switch Kit MD-S2 (914-1061-000)
Details of the MD-S2 Auxiliary Switch Kit may be viewed here
Where external wiring is connected to YBL3 Terminal M7 then the MD-S2 Auxiliary Switch Kit should be wired as follows :-
Terminal S1 (Common) - connect to 24Vac power source
Terminal S2 (Normally Closed) - connect to 24Vac device previously connected to YBL3 Terminal M7
Terminal S3 (Normally Open) - no connection necessary
Where external wiring is connected to YBL3 Terminal M8 then the MD-S2 Auxiliary Switch Kit should be wired as follows :-
Terminal S4 (Common) - connect to independent 24Vac supply
Terminal S5 (Normally Closed) - no connection necessary
Terminal S6 (Normally Open) - connect to 24Vac device previously connected to YBL3 Terminal M8
LINKAGE KIT
A Linkage Kit will also be required in order to enable the MD Actuator to be mounted on the MB Valve Body.
Linkage Kit LMD/AR-MB (914-1071-000)
Details of the LMD/AR-MB Linkage Kit may be viewed here
In such 3-wire installations the YBL3 Valve / Actuator assembly only will need to be replaced, while any associated Controller and Sensors may be retained.
