INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Air Differential Pressure Transmitter across AHU Chilled water coil

Air Differential Pressure Transmitter across AHU Chilled water coil

Air Differential Pressure Transmitter across AHU Chilled water coil

(OP)
Hello All,
We have been using Air Differential Pressure Transmitter (DPT) across filter to identify the pressure drop to take preventive action on filter maintenance. One of our customer raised a query asking "Why is it not a standard practice to use Air DPT across Chilled water coil?". Would appreciate if knowledgeable HVAC experts throw some light on this topic. Does it make a strong case to have an Air DPT across Chilled water coil? If yes, why? And if no, why? Thank you in advance.

RE: Air Differential Pressure Transmitter across AHU Chilled water coil

What would be gained from the DP information? With proper filter maintenance, the coil should be kept clean. DP would change based on airflow (if variable) and on the amount of condensation. If you were to use it to identify when your coil is clogged, I'm sure you would find out by a lack of cooling performance anyway. Just my initial thoughts.

RE: Air Differential Pressure Transmitter across AHU Chilled water coil

Coil chemical or brushing is done once in 8~10 years.There is no justification to install a monitoring for such a maintenance activity that so infrequent.Couple of ports on either side of the coil will be useful to check pressure drop once every few years

RE: Air Differential Pressure Transmitter across AHU Chilled water coil

The question is somewhat contradictory. Are you measuring DP across filter or coil? Measuring filter DP to detect when filter must be changed just cost money and is a cost/benefit analysis. HVAC systems are usually designed for absolute minimum cost.

RE: Air Differential Pressure Transmitter across AHU Chilled water coil

If you know the delta p across the filter and maintain it, there's no reason for one on the CW coil.

Condensation and differing inlet/outlet conditions on the CW coil will just mislead you.

RE: Air Differential Pressure Transmitter across AHU Chilled water coil

I suppose if you have a unique situation such as a very low temperature (<32°F) CHW system or a DX cooling system that serves a critical situation (a system that may be prone to cooling coil frost), the DP sensor and alarming might prove beneficial. I’d suggest a 0-2” or 0-5” device with a 1.0” or 1.5” alarm. Otherwise you’ll typically find a higher DP in the summer while condensation occurs on the coil and a lower DP in the winter. This would not be necessary in a typical HVAC system.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close