Diagnosis of abnormal cases

[ben9108]

I would be grateful if someone could help me to comment the following letter.

To:Manger

Further to recent case of ABC building , “mis-match” fault signal occurred due to abnormal operation of electrical valve that installed in piping system of cooling tower during normal system operation. In the meantime, operating air conditioner had been shut down and then other air conditioner and cooling tower were commanded to actuate in order to preserve system in normal condition. However, no any failure has been found from the electrical valve as result of our technician and contractor diagnosis.

In addition, another recent case occurred in XXX building, a failure of parts for electrical valve that installed in pipeline of cooling tower no.2. At the same time, common fault signal was triggered, and then air conditioner no.2 had been shut down. After a moment, Operating air conditioner no.1 had also been suspended because of lacking normal water circulation in condensing system (i.e. cooling tower no.1 keep in idling due to no changeover command generated).

In view of the captioned cases, we would like to seek your assistance in resolving the issues to avoid reoccurrence. On the other hand, we would be grateful if you would send the latest control logic of the above systems so as to our easy operation.

Engineer