Air Conditioning Question

[DSDman]

ok this may seem like a basic question but bare with me. Currently all my AC systems are feed by one water pump. that pump had it's own circuit breaker and is not connected to the ac systems in any way electrically. I'm putting in new systems and they all have a way to turn the pump on once power is turned on to the ac unit. So my question is two fold. does the water pump only come on when the compressor comes on or does it come on as soon as you put power on the ac unit. currently I just turn the pump on and water starts, then I turn the ac units on. is that bad?

[Capt.Alex]

Your current system is a little odd. There is a danger that you forget to turn on the pump and overheat the compressor. The best setup is the one where the pump comes on when the compressor cycles on, and then off with the compressor. That setup limits the amount pump run time which reduces wear and tear and fouling in the strainer and lines from constant water flow. Some older units have the third option of pump on constantly while ac system is turned on. If you have a choice, go with the system that cycles the pump along with the compressor.

[Hudson Force]

Originally Posted by DSDman

................. currently I just turn the pump on and water starts, then I turn the ac units on. is that bad?

About fifteen years ago I replaced my AC units in two cabin areas that were supplied by one pump that was wired in a manner to pump cooling water at any time either compressor was on. At the time of this replacement I did not reconnect a system for my pump to be activated by the AC compressor, but I switched on the pump separately before turning on the air conditioner. I've had no negative results by this plan. Some might point out that you may have the water filter basket clog and need cleaning more frequently, but I have not found that to be a problem. I would add that I've had my March water pumps last for over 15 years of much use, while those pretty and bright polished Taylor or Cal pumps that I tried for a while only lasted about a year each.

[DotDun]

I see no reason why you would want the pump to run when no compressor is running.

[Hudson Force]

Originally Posted by Capt.Alex

....................... There is a danger that you forget to turn on the pump and overheat the compressor. ................

I agree that there is no reason to have the water running when the compressor is not running, though admittedly, I do this. I would question the "danger" as Capt. Alex has mentioned. Certainly it is correct that you would not want your AC to overheat without the proper cooling water, but the system should have an automatic overheat cut off. Even when your water pump is timed with your compressor there will be events when you will suck a jellyfish, plastic bag or other debris against your intake and clog your waterr flow. These events will happen far more frequently than a lapse in your memory to turn on your water pump.

[GeoPowers]

Originally Posted by DSDman

ok this may seem like a basic question but bare with me. Currently all my AC systems are feed by one water pump. that pump had it's own circuit breaker and is not connected to the ac systems in any way electrically. I'm putting in new systems and they all have a way to turn the pump on once power is turned on to the ac unit. So my question is two fold. does the water pump only come on when the compressor comes on or does it come on as soon as you put power on the ac unit. currently I just turn the pump on and water starts, then I turn the ac units on. is that bad?

Hey!! Finally put 2 and 2 together!

We're at my sister's this weekend but will be back Sunday if you'd like to see our setup. Our pump comes on when the AC unit turns on- driven by the t-stat (not when it has power). For our boat this is slightly earlier than when the actual compressor kicks in.

I'd connect the start of the pump to the AC units myself. Saves wear/tear on the pump and your strainer won't clog as quickly with nettles, eels, etc.

Frank

[DSDman]

Thanks for the info guys. I guess the correct way to do this is by running all the return electrical lines into a pump relay box. That will require me to purchase said box and the extra wire and run it. At any given time any one of the four units on board could be trying to run the pump if they are all on at the same time. Although as I think about I may keep one on a separate pump since I have an unused through hull for the most forward unit. Just need to add an extra 110 breaker for it as well. Crap my units are 230v, so the pump is also 230. I don't have any more 230 open breakers. Now this is going to get complicated....maybe I'll just stick with the one. Frank is that you, dock matey?

[GeoPowers]

Originally Posted by DSDman

Frank is that you, dock matey?

Yep!

[DSDman]

I'm in DE this weekend, although I got the units today via fed ex, I also got the hot water heater so I may head back tomorrow and start the install. Or at least unload the new equipment.

[gonesail]

most self contained ac units have a special connection point for the water pump. then you just run power to the control box and hook up the thermostat.

[DSDman]

I think you are correct! that would save me the breaker spot. Thanks!