A/C water temp

C

cmariner32

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exMember
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I replaced my POS Cal pump with a March pump. The Cal pump was 580 GPH and the March pump is only 510 gph. I had called March tech support to ask them about the flow rate and they assured me that the flow rate was good for servicing up to 24,000 BTU's. I have a 12K and a 6K unit. When I first started up the system, the 12K unit shut down after about 15 mins. of run time. I hooked up city water to the water line feeding the units and blew out a lot of dirt and sediment from what I assume were laying in the coils. After hooking the units back up to the pump, everything seems to be working properly, but I was curious about the existing water temp. and it felt very warm-a rough guess would be 110-115 degrees! I never checked the water temp previously, but this seems pretty hot. Does anyone have an idea of what the water temp coming off the A/C should be? The raw water temp now hovers around 90 degrees.
 
The water coming out of the AC units should be pretty hot. That means they are doing their job of exchanging heat correctly. As long as the units are functioning correctly don't worry about it.

That said, I would boil out the units with a mild acid solution to clean the coils further and promote even better heat exchange in them. Depending on how much you run your units in a year, you may want to boil them out once or twice per year. In some cases and areas perhaps even more often.
 
Thanks Capt. I run the main salon unit 24/7 for 8-9 months of the year and hasn't been done in the 2 years that I have owner her. Based on the lack of maintenance and other jury-rigged repairs I have discovered, I doubt very much if the PO ever cleaned the coils. I planned on acid cleaning the coils this past spring, but other more urgent repairs postponed that project. Acess to both A/C units are cramped-I will have to pull the salon unit out just to get to the water lines-something that will wait until the fall/winter unless it acts up again.
 
You shouldn't have to pull the units out to flush them. Just connect the flush setup and its lines to your A/C water lines where they start at the raw water pump and end at the thruhull. At the very least pump the acid mixture through the units and then let it sit in there, depending on what strength acid solution you use, for an hour to several hours. Anything will help.

Based on where you are located and how much you run the units I would flush the at least once a year.
 
Bill...the condenser coil inlets and outlets are facing the hull side...about 6-7 inches from the backside of the unit and not accessable from the salon side. I cannot even access the points without un-anchoring the unit and sliding it inward to gain access-even then, I would have to disconnect the ductwork from the blower section. I dunno if this was the OEM install or the PO replacement install-but in either case...the existing servicing ability sucks. In a previous life, I acid cleaned prolly well over 100 large water cooled chillers in excess of 300 ton systems so I feel quite well-versed in cleaning condenser coil heat exchangers. In my experience, I never saw good results where filling the condenser with acid and letting it sit for a few hours properly cleaned scale off the condenser tubes-constant circulation and monitoring the pH and amount of foam returning was the only way to achieve proper cleaning of the condenser coils. As you say, soaking it in an acid bath may help, but I want to be able to do the job properly. Thanks for your input.
 
When faced with this situation in the past I have been able to stick a tube or fitting into the discharge thruhull with a hose on it as the return flush line and run a long peice of hose from there back to the flush bucket. Then run a hose from the flush bucket pump to the hose that comes off the raw water pump feeding the unit/s. Might be worth a try.
 
The more I think about your suggestion, the better it sounds-sometimes one can't see the forest cuz the trees get in the way. Sure will be less aggravation than pulling the unit and hose/tubing is pretty cheap. Thanks Bill.
 
cleaning the raw water side of the coils is very helpful in restoring the efficiency of the heat exchanger. use barnacle buster for this, it wont eat the copper like acid does. set up a 5 gallon pale and small bird bath pump and circulate the mix thru the system for a couple hours. works wonders for mineral deposits without destroying your equipment.
 
quote:
Originally posted by cmariner32

The more I think about your suggestion, the better it sounds-sometimes one can't see the forest cuz the trees get in the way. Sure will be less aggravation than pulling the unit and hose/tubing is pretty cheap. Thanks Bill.

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No problem. Let us know if it works out.
 
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