CYLINDER UNIT
SERVICE MANUAL
[Model Name]
EHST17D-VM2D
EHST17D-YM9D
ERST17D-VM2D
ERST17D-VM6D
EHST20D-MED
EHST20D-VM2D
EHST20D-VM6D
EHST20D-YM9D
EHST20D-YM9ED
EHST20D-TM9D
ERST20D-VM2D
ERST20D-VM6D
ERST20D-YM9D
EHST30D-MED
EHST30D-VM6ED
EHST30D-YM9ED
EHST30D-TM9ED
ERST30D-VM2ED
[Service Ref.]
Refer to page 2.
CYLINDER UNIT
ERST30D-VM6ED
ERST30D-YM9ED
EHST20C-MED
EHST20C-VM2D
EHST20C-VM6D
EHST20C-YM9D
EHST20C-YM9ED
EHST20C-TM9D
ERST20C-VM2D
ERST20C-VM6D
ERST20C-YM9D
EHST30C-MED
EHST30C-VM6ED
EHST30C-YM9ED
EHST30C-TM9ED
ERST30C-VM2ED
ERST30C-VM6ED
ERST30C-YM9ED
MAIN REMOTE
CONTROLLER
EHPT17X-VM2D
EHPT17X-VM6D
EHPT17X-YM9D
ERPT17X-VM2D
EHPT20X-MED
EHPT20X-VM6D
EHPT20X-YM9D
EHPT20X-YM9ED
EHPT20X-TM9D
EHPT20X-MHEDW
ERPT20X-MD
ERPT20X-VM2D
ERPT20X-VM6D
EHPT30X-MED
EHPT30X-YM9ED
ERPT30X-VM2ED
ERPT30X-VM6ED
CONTENTS
TECHNICAL CHANGES ....................................... 3
1. REFERENCE MANUAL ................................... 4
2. SAFETY PRECAUTION ................................... 5
3. SPECIFICATIONS ............................................ 7
4. PART NAMES AND FUNCTIONS ................. 11
5. OUTLINES AND DIMENSIONS ..................... 13
6. WIRING DIAGRAM ........................................ 15
7. FIELD WIRING ............................................... 21
8. WATER SYSTEM DIAGRAM ......................... 25
9. CONTROLS ................................................... 29
10. TROUBLESHOOTING ................................... 50
11. DISASSEMBLY PROCEDURE ...................... 67
12. SUPPLEMENTARY INFORMATION ............. 88
13. SERVICE AND MAINTENANCE ................... 89
PARTS CATALOG (OCB714)
October 2020
No. OCH714
REVISED EDITION-B
Revision:
• EHST17D-VM2DR1.UK, EHST17D-
YM9DR1.UK, ERST17D-VM2/6DR1.
UK, EHST20D-MEDR1.UK, EHST20D-
VM2/6DR1.UK, EHST20D-YM9DR1.
UK, EHST20D-YM9EDR1.UK,
EHST20D-TM9DR1.UK, ERST20D-
VM2/6DR1.UK, ERST20D-YM9DR1.
UK, EHST30D-MEDR1.UK, EHST30D-
VM6EDR1.UK, EHST30D-YM9EDR1.
UK, EHST30D-TM9EDR1.UK,
ERST30D-VM2/6EDR1.UK, ERST30D-
YM9EDR1.UK, EHST20C-MEDR1.UK,
EHST20C-VM2/6DR1.UK, EHST20C-
YM9DR1.UK, EHST20C-YM9EDR1.UK,
EHST20C-TM9DR1.UK, ERST20C-
VM2/6DR1.UK, ERST20C-YM9DR1.
UK, EHST30C-MEDR1.UK, EHST30C-
VM6EDR1.UK, EHST30C-YM9EDR1.
UK, EHST30C-TM9EDR1.UK,
ERST30C-VM2/6EDR1.UK, ERST30C-
YM9EDR1.UK, EHPT17X-VM2/6DR1.
UK, EHPT17X-YM9DR1.UK, ERPT17X-
VM2DR1.UK, EHPT20X-MEDR1.UK,
EHPT20X-VM6DR1.UK, EHPT20X-
YM9DR1.UK, EHPT20X-YM9EDR1.
UK, EHPT20X-TM9DR1.UK, EHPT20X-
MHEDWR1.UK, ERPT20X-MDR1.UK,
ERPT20X-VM2/6DR1.UK, EHPT30X-
MEDR1.UK, EHPT30X-YM9EDR1.UK
and ERPT30X-VM2/6EDR1.UK have
been added
• Some descriptions have been modified
in REVISED EDITION-B.
OCH714A is void.
Note:
• This manual describes service data of
cylinder unit only.