A/C cooling water flow alarm

[Keith]

One of my A/C's shut down today due to low cooling water flow. I cleaned the strainer out and got them running again, but it got me thinking...what would be a good way to give me a status so I could clean it out before they stopped?

First thought would be a water flow rate alarm like I have on my engine cooling water. You adjust it so that when the flow gets below a certain value, it alarms. Besides that, what ideas do the rest of you have? Maybe a vacuum gage that shows the restriction at the strainer? Any other ideas?

 

[Rollsdoc]

On Rollsdoc we have FX digital controls that have temp sensors on the condensors. When that temp reading goes up I know it's time to check the strainer.

 

[Daddyo]

Rollsdoc I sent you a PM

 

[Keith]

Well young man, there is no note passing allowed in class. You had better read it aloud to everyone...

 

[Chris Foster]

Probably a temperature sensor would be the cheapest and least invasive... flow and suction sensors aren't inexpensive or simple.

You could probably measure the water outlet temperature with the strainer clean on a warm day and add 10 or 15 degrees to that, and use that as an alarm point.

Grainer probably has some remote temperature sensors with alarms that'd work just dandy.

 

[Forkliftt]

Sometimes we don't get to the boat for 2 weeks, AC on constantly. Our current slip, like most, seems to have enough cr** in the water to plug the AC strainer @ times. Unit shuts off. *Has anyone installed a larger capacity strainer and seen positive results? How about a conversion to digital controls? Could run the unit 6 hours a day or so, effectivley knocking out 2/3 of the water flow. Thoughts??

 

[Rollsdoc]

Digital gets my vote. With them you can set it on away mode and it will come on every 4 hours until temp drops about 4 degrees. Good ones are not cheap. Sounds like you have old analog controls. If so you could add a pump relay or control that would only run the pump when a compressor is running.Many years ago we installed Sendour strainers on all water intakes. Checked our AC strainer Sunday for the first time in months and it was clean. Sometimes it will grow a beard and someone needs to get in the water and pull it off. About once a mouth I back flush with 65 psi city water.
Last year when we replaced the transmissions I removed the sea strainers for the engines because they hadn't needed cleaning since we installed the strainers on the bottom side. Can't remember the last time the genset strainers or watermaker strainer needed cleaning. Location makes a diff. But we're up a river with lots of debree (neighbors complain)
We don't run the ACs away from the dock and we're at a dock for only 4-5 months/year, sometimes less.

 

[Keith]

The "stuff" won't grow as well if the water isn't flowing, so intermittent operation will help, as will a larger strainer. Here's the aftermarket digital control I installed on one of my AC's, and it works very well. Has the dehumidifier function you mention.
http://coastalclimatecontrol.com/index.html

Another big help is to put a strip of copper foil, piece of copper tubing, etc. in there. It will act just like the copper anti-fouling bottom paint and reduce the growth in there. I've done this for years and it makes a significant difference. Stuff will still grow in there, but not nearly as fast. I also break up a Clorox toilet bowl tablet in half and put half in the strainer every time I clean it. This helps kill stuff in there and downstream.

 

[Forkliftt]

Good advice,Thanks