IWAKI AMERICA Walchem W900 Operating instructions

W900 Quick Programming Guide
W900 Biocide Programming Guide
ONLY AVAILABLE IF HVAC MODES ARE ENABLED IN CONFIG MENU – GLOBAL SETTINGS
Basic Biocide Operation
How the Biocide Addition works:
When a biocide event triggers, the controller will first prebleed (if a prebleed is programmed)
for the set amount of prebleed time or down to the set prebleed conductivity. Then the biocide
relay is turned on for the set duration. This is followed by a post-bio add lockout that blocks the
bleed relay from turning on for a set amount of bleed lockout time.
You can program when, how often, and for how long the biocide comes on, in addition to a pre-
bleed and a lockout (after the biocide addition) as mentioned above.
When in the Biocide mode, you program *Events* for the relay. And Event means that the
output is turned on at the same time of day, for the same amount of time, and except for the
Daily cycle, on the same day of the week.
When programming the event, you select the Repetition of the biocide event, (Daily, Weekly, 2
Week, 4 Week, None), the Day and the Time the relay comes on.
Enable HVAC Mode
Start from the Main Menu (from the home screen press and then Config
1. Press Config
2. Press Global Settings
3. In Config > Global Settings, you can enable HVAC Modes.
Programming the Biocide Timer Control Mode
The following instructions will show examples of how to program the controller for biocide feed on a
Daily, Weekly, 2 Week, 4 Week, and None basis.

W900 Quick Programming Guide
Daily Biocide Feed
Start from the Main Menu (from the home screen press and then Outputs
1. Select which relay that you want to use. For example, R2
2. Press R2
3. Press settings
4. Scroll to the last field, press Mode
5. Scroll down and press Biocide Timer
6. Press settings
7. Press HOA Setting and select Auto
8. Press Event1
9. Press Repetition
a. Select the time cycle to repeat the event: Daily, 1 Week, 2 Week, 4 Week, or None. An
event means that the output is turned on at the same time of day, for the same amount
of time, and except for the Daily cycle, on the same day of the week.
10. Press Daily and then press the
11. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
12. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
13. Press and then Press Event 2
14. Press Repetition
15. Press Daily and then press the
16. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
17. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
18. To add another event to the Daily schedule, press and then Press Event 3 to add the 3rd
Daily event and repeat the programming instructions above
a. You can add up to 10 Events Daily

W900 Quick Programming Guide
Weekly Biocide Feed
In this example, we will feed biocide 3 days per week (Monday, Wednesday, and Friday) for 1 hour each
day
Start from the Main Menu (from the home screen press and then Outputs
1. Select which relay that you want to use. For example, R2
2. Press R2
3. Press settings
4. Scroll to the last field, press Mode
5. Scroll down and press Biocide Timer
6. Press settings
7. Press HOA Setting and select Auto
8. Press Event1
9. Press Repetition
a. Select the time cycle to repeat the event: Daily, 1 Week, 2 Week, 4 Week, or None. An
event means that the output is turned on at the same time of day, for the same amount
of time, and except for the Daily cycle, on the same day of the week.
10. Press 1 Week and then press the
11. Press Day and select the day of the week that you want Event1 to occur
a. Press Monday and then press
12. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
13. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
14. Press and then Press Event 2
15. Press 1 Week and then press the
16. Press Day and select the day of the week that you want Event2 to occur
a. Press Wednesday and then press
17. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
18. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press

W900 Quick Programming Guide
Weekly Biocide Feed (continued)
19. Press and then Press Event 3
20. Press 1 Week and then press the
21. Press Day and select the day of the week that you want Event3 to occur
a. Press Friday and then press
22. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
23. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
2 Week Biocide Feed
In this example, Week#1 we will feed biocide 3 days per week (Monday, Wednesday, and Friday) for 1
hour each day; And Week#2 we will feed biocide 2 days per week (Tuesday and Thursday) for 1 hour
each day
Start from the Main Menu (from the home screen press and then Outputs
1. Select which relay that you want to use. For example, R2
2. Press R2
3. Press settings
4. Scroll to the last field, press Mode
5. Scroll down and press Biocide Timer
6. Press settings
7. Press HOA Setting and select Auto
8. Press Event1
9. Press Repetition
a. Select the time cycle to repeat the event: Daily, 1 Week, 2 Week, 4 Week, or None. An
event means that the output is turned on at the same time of day, for the same amount
of time, and except for the Daily cycle, on the same day of the week.
10. Press 2 Week and then press the
11. Press Week and then select Week#1, and then press
Week#1

W900 Quick Programming Guide
2 Week Biocide Feed (continued)
12. Press Day and select the day of the week that you want to feed
a. Press Monday and then press
13. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
14. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
15. Press and then Press Event 2
16. Press 2 Week and then press the
17. Press Week and then select Week#1, and then press
18. Press Day and select the day of the week that you want Event2 to occur
a. Press Wednesday and then press
19. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
20. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
21. Press and then Press Event 3
22. Press 2 Week and then press the
23. Press Week and then select Week#1, and then press
24. Press Day and select the day of the week that you want Event3 to occur
a. Press Friday and then press
25. Press Start Time
a. Enter the time of day to start the event (this is military time) and then press
26. Press Duration
c. Enter the amount of time that the relay will be on
d. In this example, 01 HH 00 MM 00 SS then press
Week#1
Week#1
Week#1

W900 Quick Programming Guide
2 Week Biocide Feed (continued)
Press and then Press Event 4
27. Press 2 Week and then press the
28. Press Week and then select Week#2, and then press
29. Press Day and select the day of the week that you want Event3 to occur
a. Press Tuesday and then press
30. Press Start Time
31. Enter the time of day to start the event (this is military time) and then press
32. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
Press and then Press Event 5
33. Press 2 Week and then press the
34. Press Week and then select Week#2, and then press
35. Press Day and select the day of the week that you want Event3 to occur
a. Press Thursday and then press
36. Press Start Time
37. Enter the time of day to start the event (this is military time) and then press
38. Press Duration
a. Enter the amount of time that the relay will be on
b. In this example, 01 HH 00 MM 00 SS then press
4 Week Biocide Feed
The 4 Week feed programming works just like the 2 Week feed programming, except that now you have
Week#1, Week#2, Week#3, and Week#4 to choose from instead of just Week#1 and Week#2
For example:
1. Press Event1
2. Press Repetition
3. Press 4 Week and then press the
4. Press Week and then select Week#1 (or Week#2 or Week#3 or Week#4), and then press
5. Press Day and please continue as instructed in the 2 Week Biocide Feed programming section of
this Quick Programming Guide
Week#2
Week#2