Air Conditioner- Not Pumping Raw Water Out of Hull

[VerBoatin]

Hello Everyone,
A/C was working really well on my 34' Wellcraft Gran Sport. Then on 4th of July evening, I tried to run A/C off the gen set. I noticed it wasn't cooling the cabin and no water coming out of the hull discharge. I shut the A/C down and tried it again in the slip the next day with 110V shore power instead of gen set 110V. Again, no hull water discharge like before and I noticed a "vibration" and "grumbling" in the floor which I believe to be the A/C raw water pump. It sounds like it is going or has gone bad or something is amiss in the pump. I saw a thread here that discussed disconnecting the raw water line at the heat exchanger (I assume this is found at the air conditioning unit itself which is located under the seat at the table/kitchenette area?), and forcing water back (opposite direction it normally flows) through the system to ensure there is no blockage and such in the line or the raw water inlet. If the pump is in need of replacement, I assume I will need to lift up the carpet and access the pump and motor via removal of the long inspection board located in the floor of the cabin (at the place where I heard/felt the vibration, etc)? Any recommendations, advice, warnings, or suggestions are welcome and if one can comment on the difficulty factor involved in changing the A/C raw water pump, I would greatly appreciate your comments. Also, I read something about March pumps being better than Cal pumps? I'm not familiar with either brand or these pumps at all for that matter so any information is quite welcome! Thank you much in advance!
VB

 

[pole position]

Re: Air Conditioner- Not Pumping Raw Water Out of Hull

Pull the discharge hose off at the pump,turn on the air and see if it pumps water.If not make sure it has power when air is turned on.Ac pumps usually don't give any warning when they quit.As far as the pumps (March or Cal) go,I'd use what ever brand you have.I've had both brands and they worked fine.

 

[Fireman431]

Re: Air Conditioner- Not Pumping Raw Water Out of Hull

This might be long, so sorry in advance:

If you have a vibration in the floor, there may be more than one issue to deal with. You mave pulled and obstruction into the raw water intake and the AC pump, although small, will cause a ruckus when cavitating. The easiest way to check is to close the seacock, remove the incoming hose from the water pump (then open the seacock) and backflush it with a strong stream from a garden hose. The close the seacock again and put the garden hose into the open end of the water pump and see if water then flow thru the rest of the system and out the discharge. Retry the AC.

In the event you don't get any water coming thru the discharges, move up thru the chain of parts until you find the blockage. Thes means the hose from the (outgoing) water pump, incoming and outgoing at the coil, and any fitting in between. If your AC water pump impeller failed, it might have sent plastic pieces throughout the system, causing more than one blockage. The only good news is that most blockages are between the raw water intake and the water pump. Obviously, make sure your sea strainer is clear as well.

Other possible issues:

Hose from the sea strainer to the water pump is degrading and is collapsing on the inside, starving for water. Remove and inspect.
Clogged sea strainer
Damaged water pump (impeller). Run soap/bleach thru about once a month to maintain it.
Clogged outgoing line from the water pump to the AC unit.
Clogged condenser line. Remove water discharge hose and backflush thru the coil. Also flow water thru the discharge hose and make sure no obstructions. To help keep condenser coils clean, flow some bleach or muriatic acid thru the system and flush well afterward. Removes gunk, mildew build-up.
Blown fuse for water pump (AC unable to get water, so it won't even kick on. Test with a multimeter or testlight.
AC computer faulty, which won't let the AC water pump kick on. The pump should be wired to an AC computer so that if the AC is being activated, the water pump kicks on approx 30 sec-1 min prior.


Keep us posted!!

 

[VerBoatin]

Re: Air Conditioner- Not Pumping Raw Water Out of Hull

Thank you VERY much for your guidance...I appreciate the feedback and particularly on the troubleshooting and pumps! VB

 

[VerBoatin]

Re: Air Conditioner- Not Pumping Raw Water Out of Hull

PLEASE!...no apology for the response length...sheesh! I really appreciate your writing back with such detail. This is fantastic troubleshooting guidance and I'll follow the procedures you set forth step by step and see what I can find out. I will certainly keep you posted and again, MANY thanks for this great advice!
VB