![background image](http://html1.mh-extra.com/html/mcquay/ac-40a/ac-40a_applications-manual_1756089145.webp)
The switch in the flow switch is a SPDT (Single Pole, Double Throw) type. It has a common
terminal and two contacts. One contact will activate when there is an increase in flow, whereas
the other will activate when there is a decrease in flow. Each flow switch will have it's own
'activation' flowrate setting. Appendix 17 gives an example for such settings for the F61 flow
switch.
COMMON
SPDT
INCREASE (NO)
DECREASE (NC)
Note: We can also call the 'decrease' contact as Normally Close (NC) contact whereas the
'increase' terminal as Normally Open (NO) contact.
When water flows through, the NC contact will open and the NO contact will close.
In the mini chiller unit, the NO contact is connected to the PCB controller via the FS terminal.
When the contact closes, a 12V signal is received by the controller indicating that the water flow is
OK. When the contact opens, the absence of this signal will prompt the controller to give an error
code 'FS' on the LED display.
Some of the typical problems encountered when the FS error code occurred are:
a. the paddle has broken/cracked/twisted
b. the paddle has stuck in the pipe
c. the switch mechanism has jammed - e.g. due to debris
d. wrong wiring of the NO and NC terminals (reversed)
e. failure of the switch contacts - e.g. due to shorting
f. wrong adjustment setting of the switch
g. air lock in the water pump
h. insufficient water in the system
In the event that the flow switch must be replaced:
1. Drain out all the water in the system.
2. Remove the wiring connections in the switch and remove the switch from the tee adaptor.
3. Replace with a new switch and reconnect the wire. Manually test the switch by pushing
the paddle. If OK, there should be an audible 'click' sound. Check sufficient length of paddles.
Screw the switch back into the piping.
4. Refill the system with water. Purge out any air by releasing the air lock hole on the pump.
5. Check for water leakage.
6. Test run and confirm switch operation.
Section 12
Page 143
Содержание AC 40A
Страница 1: ...AM MAC ...
Страница 153: ...Appendix 1 ...
Страница 154: ...Appendix 2 Appendix 2 ...
Страница 157: ...GRAPH OF PRESSURE DROP VS FLOW FOR VARIOUS C V RATINGS Appendix 5 1 ...
Страница 158: ......
Страница 159: ...Water Capacity Graph Appendix 5 2 ...
Страница 160: ...CHART 3 FRICTION LOSS FOR CLOSED PIPING SYSTEMS Appendix 6 1 ...
Страница 161: ...CHART 4 FRICTION LOSS FOR OPEN PIPING SYSTEMS Appendix 6 2 ...
Страница 162: ...CHART 5 FRICTION LOSS FOR CLOSED AND OPEN PIPING SYSTEMS Appendix 6 3 ...
Страница 168: ...Appendix 8 Appendix 8 ...
Страница 169: ...Appendix 8 1 ...
Страница 170: ...Appendix 8 2 ...
Страница 171: ...Appendix 8 3 ...
Страница 172: ...Appendix 8 4 ...
Страница 173: ...Appendix 8 5 Appendix 8 5 ...
Страница 174: ...Appendix 8 6 Appendix 8 6 ...
Страница 175: ...Appendix 8 7 Appendix 8 7 ...
Страница 176: ...Appendix 9 ...
Страница 178: ...Appendix 11 1 Appendix 11 1 ...
Страница 179: ...Appendix 11 2 Appendix 11 2 ...
Страница 180: ...Appendix 13 ...
Страница 181: ...Appendix 13 1 ...
Страница 182: ...Appendix 14 Appendix 14 ...
Страница 183: ...Appendix 15 1 Appendix 15 1 ...
Страница 186: ...Appendix 17 Appendix 17 ...
Страница 187: ...Appendix 18 ...
Страница 188: ...CE20DW CE25DW Note PRESSURE DROP CORRECTION FACTOR 1 2947 0 0021 EWTºF Appendix 19 ...
Страница 189: ... 2003 McQuay International 603 55194922 www mcquayup com ISO 9002 REGISTERED ...