Questions about A/C

[airdvr1227]

Our new to me 1989 Carver is having A/C problems. Symptoms...Ocean Breeze air blows ice cubes than stops unexpectedly.

Part of the deal with the marina we purchased was to fix the A/C. Originally I thought the stream of water coming out the discharge was weak in comparison to other systems I've seen. The tech agreed and replaced all of the piping from the ball valve on the thru hull, to the strainer and to the pump. He also replaced the pump. We thought we had the problem solved. The discharge stream is much better now but, the air was working and again shut down unexpectedly. The stream was still exiting the discharge. When I looked at the unit under the birth the coils were frozen solid. A friend told me when the coils freeze it means one of two things; low refrigerant or poor air circulation.

We let it thaw and re-started the system. This time I put a box fan forcing air into the cold air return. I set the thermostat for 72. Seemed to be working fine but when the inside temp hit 72 the unit did not shut off. We left and came back only to find the discharge stream really weak.

Question 1; the thermostat is from a Hunter unit. It is not the original equipment. I'm thinking it's not working correctly because it didn't shut off the system when it reached 72 degrees.

Question 2; it appears algae has plugged the thru hull seawater pickup. How do I keep that from occurring?

Thanks in advance.

 

[midcarolina]

There are several other issue's that can cause the evap to freeze, but low air flow or low refrigerant are the two most common.....pictures would really help.
The water cools the condenser, lack of water flow would cause a no air situation but not freezing of the evap, the system may have a head pressure control on the condenser water.......it modulates based on system head pressure........

1) are you sure the evap coil is clean and unobstructed?
2) do you have and know how to use a multi meter?
3) With the coil thawed check your return air temp and your supply air temp.and post your results
4) how many and what size are the supply and return ducts.

Thermostat could be several degree's off and still work fine....set the stat to what feels comfortable and see if it satisfies and shuts unit off
If the thermostat will not shut unit off on temp. that can explain the freeze up also

 

[airdvr1227]

Thanks mid. Coil looks clean to me. I'm assuming it would be obvious if it weren't clean? Yes, I have and can use a multi-meter. Check on the temp check. There are 2 supply vents and one large return vent.

Any ideas on how to keep the algae away from the pickup?

 

[airdvr1227]

Thanks mid. Coil looks clean to me. I'm assuming it would be obvious if it weren't clean? Yes, I have and can use a multi-meter. Check on the temp check. There are 2 supply vents and one large return vent.

Any ideas on how to keep the algae away from the pickup?

 

[midcarolina]

If algea/crud is clogging up the pickup quick due to water conditions, you may have to pipe in a backflush to periodically clean out the pickup

yes the coil condition should be fairly obvious........ take a flashlight and shine through the coil, but usually if the coil face is clean it's good.

If you can get to it check the blower wheel and make sure there isn't any debris in there........ you would be surprised how many times I have seen sandwich bags blocking the vanes of the wheel.