AC on 3807 has been fited with thermostats, how to start pump first.

[justtls]

Greetings and thank you for taking the time to read this. I recently purchased an 88 3807 that has been fitted with thermostats instead of the 3 switch controls of the past. Historically when I would turn on the AC in my other boats I would turn the AC knob to start, then check to see that water was being discharged then turn AC to run or soemthing like that. Anyway now the unit just comes on all at once but I dont see any water being discharged. I checked the through hull, the screen, the impeller and all look fine. Do I need to prime this system with water somehow or should I just let it run a bit longer and see if the water comes through. I have only run it for about 2 minutes at a time so far. Any help would be greatly appreciated, thanks.

tls

[g36]

can you provide more info as to what brand ac units? cruisair? is there only one ac pump for multiple ac units? if multiple there will be a relay control box. if you checked the parts listed on your post when the ac is on have you placed your hand on the pump to see if you feel it running?

[justtls]

Thanks for the response. These are Cruisair 16, 12 and 9 BTU Systems. I have tried all three briefly but turn them off when I didnt see any water coming out of the exit ports on the side of the boat. I decided to give my attention the 16KBTU in the main Salon. It appears that everthing comes on with the thermostat, the system itself, the compressor and pump. I also found that the system has a standalone intake pump connected to a throughput intake valve with a screen filtered valve in between. This pump comes on as well as I can hear it and feel it running. I checked water flow up to the pump and even pulled the front off the intake pump and checked the impeller and all appears ok. I did see something somewhere about a person priming a like system but I would no where to start, what to prime etc. Dose anybody have a system like this? Any info would be greatly appreciated as you all well know the heat and humidity is getting pretty fierce on the Bay.
Thank you for your time. TLS

[g36]

do you think that the pump might be frozen and not really turning? if you feel the pump running and the inlet and outlets are clear then you need to get some water flowing someway. the ac pumps should be self priming but i am not there so it could be an air lock on the intake pump side. if you say the pump is running you could remove the outlet hose from the pump and apply power to the pump to see if you are pumping any water out of it say into a bucket etc. if so you may get lucky and reconnect it and your good to go. if not to check for a restriction in the lines you could also disconnect the same hose and attach a water hose from the dock etc. and turn it on and watch for water flowing out of the discharges on the outside of the boat where the normal ac water should be coming out. you dont need to have the ac units on for this. it wont hurt if you did they will start cooling like there supposed to do. all the water is doing is cooling the coils and flowing back out of the boat same principal except with air flow as the fan on your home ac does. so as long as you have water flowing through the system then the heat will be removed and the ac units will work. so its not high tech here just got to get some water going through the system one way or the other. if you dont get any water through with the garden hose then there is some restriction somewhere in the lines, if so then systematically go through it and troubleshoot. then you can repair whats wrong

[waybomb]

Is there a strainer before the pump? Should be two wingnuts on top. Open the seacock and unscrew the nuts most of the way. Until water comes gushing out. Then tighten the wingnuts back down tight so no water is coming out. Then go to the pump and loosen its wingnuts until water comes out. Then close those wingnuts.
Now when the pump runs, you should see water coming out of the three drains.

The pump is a centifugal pump and needs to be primed, which is what I just described.

[Ondercin]

Put your garden hose in the outlet and turn it on.. then look at all the hoses you can see and feel the hose to see if it gets cooler.. that means water is passing through it, check for leaks by the time you would have done this the system will be primed. Pull the hose out of the outlet and turn on the system

[justtls]

Thanks for your help on this issue. I need to back up just a bit here, sorry. I found that these are MarineAir systems not CruiseAir. Also it appears that just the Fans are coming on and not the compressor, that would account for no water coming out the throughput. It looks like I may not be getting enough power to start the compressor as the Panel does show 125 volts but the Amp meter is not showing much movement at all. Could this be a bad power cord on my shore power? Im currently connected to one 50 Amp pole for the AC side and one 30 Amp pole for the rest of my power needs. The 50 Amp cord has a "Y" cord adapter on the pole side leaving one side of the adapter open/empty. Not sure why they have that on there other than the fact the power cord itself doesnt seem to fit into the pole socket by itself. Im thinking about trying an adapter without the "Y" cord to see if maybe the "Y" could be bad. BTW the 3807 has two power inlets and they both say 50 AMP on the inlet/outlet, are they in fact both 50 AMP? Anybody ? Thanks again... Have a great weekend. Unfortunately with out any AC my time on the boat is limited until I get this figured out.

[Ramsport47]

If they are the new digital thermostats, the pump will only run while the AC compressors are running. There is no need for the pump to run unless the compressors are functioning. The thermostats control when the pump turns on and off

[Viper]

Hi folks, I'm new here. Hope I can contribute some useful info.

I agree with the above. The pump is controled by the board and will only operate when the compressor switches on.

If you're sure the pump is running and you have water getting to the pump, have someone standing by at one of the ac control panels in order to turn off and on at your command. Slightly loosen the screws on the front of the pump face and have the person turn the ac on. Continue loosening screws until the pump starts forcing water out between the two halves. You will note the difference in the sound of the pump when it actually starts pumping water through the system. Tighten the screws as quickly as possible as it will get messy so be prepared. if it gets out of hand, have your partner shut the ac off. After it's tightened up again, confirm operation by turning one of the units on again after allowing the system to rest for about 15 minutes so you're not forcing the compressor to deal with high head pressures.

It should be noted that on my 3807, the salon and aft units discharge right at the aft waterline. You can barely see or hear the discharge unlike most applications that shoot out the side of the hull. The forward unit does discharge out the side at the bow.

Yes you have two 50 amp services.

Hope that helps.

[waybomb]

On a newer unit I installed on my boat, there is a delay, a good 5-10 seconds, between the air fan turning on, and then the compressor and water pump.

If you have water at the pump, it will flow. Unless the lines a plugged up with junk. A buddy had that issue, and he did have a large Perko strainer before the pump.