1990 3807 heat/air issue

[Washopay]

Anybody know the make of the heat/air units in 1990 3807s? Or where I can get a manual to do some troubleshooting?

[tomschauer]

I don't know what manufacturer Carver used in 1990, others on this forum may. But if you are not the original owner, there is a good chance the unit(s) may have been replaced somewhere along the line. There should be a make / model number somewhere on the unit, normally on the control box. If not you may want to make sure the power is off and remove the control box cover. The make / model and wiring diagram should be on the back side of the cover.
A couple things to look for...
When you turn the stat on do you have water flow from the pump through the unit and discharging from the boat? If not you need to start here.
If you have water flow, does the compressor try to start? If not look for the high pressure switch. the older units had a manual reset switch, usually a red button on one of the copper lines near the discharge of the compressor. Some also had a low pressure switch, normally a blue button on the larger copper line near the compressor.

If the high pressure was tripped, you most likely ran the unit without water flow. If the low pressure tripped, you most likely need to clean the filter if it has one and the evaporator coil.


Give some more info and I am sure help can be provided.

Tom

[Washopay]

Hi Tom. Thanks for the guidance. You've given me a great place to start and I'll let you know how I make out

[Washopay]

Hey Tom. It's a Marine Airrrrrr. The pump runs and discharges. The compressor kicks in. I could see no evidence of low pressure or reset switches.

image.jpeg

. This is the model. Any ideas on how to proceed? Pressure test, drain and refill? Thanks!

[tomschauer]

Ok, I assume the fan runs? And if the compressor runs, does it continue to run? If so, in the ac mode you should get a temp drop between the ambient air and the discharge air from the unit. This should be at least 10 degrees after it has been running for 10 minutes or so. If the temp drop is much higher and the coil starts to frost, it is most likely a dirty coil. If you have little or no temp drop you most likely lost refrigerant.

Let me know.
Thanks

[Washopay]

It's been a while since I was on this (other problems). No drop in temp. Checked the refrigerant and recharged it. No drop in temp. The pump and the compressor both run. I'm stumped.

[waybomb]

Is this aheat/ac unit?
If so, I believe there is a three way valve in the refrigerant line.
Check the electrical connection there.

Ps, I never dug into one of these, my knowledge is from working on Thermo kings many years ago on refrigerated trailers.

[tomschauer]

was there any refrigerant in it? If not did you find and repair the leak? If so did you remove the refrigerant, evacuate the system and add 12oz of r-22?

[Viper]

Have you checked to see if the heat cycle works? Reversing valve may be stuck.

[Washopay]

I drained, recharged, checked for leaks. Nothing worked. Until this weekend. I turned it on . Out came ice cold air. I think I forgot to say abracadabra in the spring. Stupid me.