HVAC problems

[budzuk]

Boat is new to me. 1989 sabreline the 2 air systems turn on and cool but cycle off because raw water pump (rwp) does not run. All systems are on separate breakers and none of them trip. I pulled the pump and it bench tested ok and ran. I am not familiar with boat A/C does the RWP run all the time and units cycle on and off. I need info on trouble shooting. Thanks in advance.

Budzuk

[Underway]

Originally Posted by budzuk

Boat is new to me. 1989 sabreline the 2 air systems turn on and cool but cycle off because raw water pump (rwp) does not run. All systems are on separate breakers and none of them trip. I pulled the pump and it bench tested ok and ran. I am not familiar with boat A/C does the RWP run all the time and units cycle on and off. I need info on trouble shooting. Thanks in advance.

Budzuk

The raw water pump for our two Cruiseair units only comes on when one of the compressors starts. When it runs, it is pumping raw water through both units...even if one is not running.

[mbevins]

The Cruise Aires on mine run continuous as soon as the AC is turned on. It's circa 1987 basically the same as yours. I believe it was in the later years that they started cycling the RWP with the compressor. Have you checked for voltage at the pump motor when the compressor comes on. If so bad motor if not check the relay upstream.

Sent from my Nexus 7 using Trawler

[psneeld]

can be set up either way...the pump can be breakered to run all the time or go to a relay that kicks it on whenever an A/c unit demads it.

mine was set up to run all the time but when I replace the a/cs next year I pland to spring for the relay that allows either a/c to kick on the pump.

[fryedaze]

I have 1989 units and they have fuses in the control boxes. I have two compressors that run three air handles. There are fuses in the three control boxes that may be causing the problem. had a similar problem and it was solved by replacing the blow fuse.

[Capt.Bill11]

Open the control box that the pump is wired into. Check the fuses if there are any. If the system is set up where the pump only comes on if one or both of the compressors are running then you my have a bad triac. A triac is the switch that sends power to the pump when it senses that a compressor has kicked on.

If you have a system that uses a triac it's handy to add a bypass switch so when the triac fails you can bypass it and power the pump directly to run full time until you can replace the bad triac. It's also handy to carry a extra triac in your spares kit.

[Underway]

Originally Posted by Capt.Bill11

Open the control box that the pump is wired into. Check the fuses if there are any. If the system is set up where the pump only comes on if one or both of the compressors are running then you my have a bad triac. A triac is the switch that sends power to the pump when it senses that a compressor has kicked on.

If you have a system that uses a triac it's handy to add a bypass switch so when the triac fails you can bypass it and power the pump directly to run full time until you can replace the bad triac. It's also handy to carry a extra triac in your spares kit.

This jogs my memory. Both of our units suffered triac failures several years ago when the boat was plugged into a faulty shore power box and kept getting voltage spikes. I went to www.marine-ac.com for some very good on-line trouble shooting help. If it's a later Cruisair unit with Triac switches, the trouble shooting goes like this...

Find the triac (roughly 3/4 inch square black block with three male electrical connectors...potted on a metal bracket with a screw on either end). Identify yellow, purple, and black wires and note their locations.

Disconnect the yellow wire. If the compressor keeps running, the triac is likely bad.

Now pull the purple wire (with the yellow still disconnected). If the compressor stops, but the fan keeps running, it is almost certainly a failure of the triac.

If you isolate the problem as a triac failure get the number off the switch. The one on our Cruisair is SANREX TG35F60. Go on line and find it at an electrical supply house. The cost will be about one third of what a local marine AC shop will charge. As mentioned above, buy a spare (about $9 on line).

[cafesport]

Originally Posted by budzuk

Boat is new to me. 1989 sabreline the 2 air systems turn on and cool but cycle off because raw water pump (rwp) does not run. All systems are on separate breakers and none of them trip. I pulled the pump and it bench tested ok and ran. I am not familiar with boat A/C does the RWP run all the time and units cycle on and off. I need info on trouble shooting. Thanks in advance.

Budzuk

Sounds like it could be the pump trigger relay. It's good to have a spare anyway so you might as well order one and give it a try.


Via iPhone.

[Shoalwaters]

If you have Cruisair's and they are of mid/late 80's vintage (mine were) then the box with the triggers/Triacs/relays probably looks like this. I replaced mine with a breaker - IMHO one less thing to go wrong.

[CaptTom]

This might be a dumb question, but are you sure the pump is not running? I'm not trying to question your intelligence, just that a pump losing its prime is the most common cause when there's no water flow, assuming there's no plugged intake or hoses.

[capt jerry]

Originally Posted by budzuk

Boat is new to me. 1989 sabreline the 2 air systems turn on and cool but cycle off because raw water pump (rwp) does not run. All systems are on separate breakers and none of them trip. I pulled the pump and it bench tested ok and ran. I am not familiar with boat A/C does the RWP run all the time and units cycle on and off. I need info on trouble shooting. Thanks in advance.

Budzuk

could be the trigger assembly they can be fixed to run the punp all the time or only when the ac is turned on, been there done that

[Ski in NC]

I put a switch near the breaker panel so pump can be started without starting AC's. Nice to see the flow and know it is primed. Note my pump has a habit of air loading after a long run offshore in rough stuff, so this was my fix. Or better put, my bandaid.