Marine Air heat won't start

[405driver]

I have a Carver 405. The forward Marine Air unit (VRP 16K) will run in the cooling mode but will not switch on in the heating mode.T he heat light on the Passport II control panel does not come on when calling for heat. I ran the diagnostic test (power switch pressed while turning on the AC power) and the heat runs for its allotted 10 minutes. During the test the heat light on the control panel illuminates as it should.

I would think that the diagnostic is bypassing something while executing the test, but have no idea what?? Since it acts normal during the test it doesn't seem to be the reversing valve, and I would think that the unit itself is OK. Maybe a loose wire, circuit board (however no codes displayed) or the controller head.

Any ideas would be appreciated.

[Viper]

To eliminate the control panel as a possibility, disconnect one from another location and plug it into the faulty location, then try. If the heat works, it's a faulty control panel.

[405driver]

Thanks...good idea.

Do you know how the remove the control panel? I noticed a very small button on the bottom of the panel but not knowing what it is, I was afraid to push on it very hard.

[Viper]

Most of the ones I've seen are usually just stuck on with two sided tape. Be careful what you push, I think those have a temp probe on the bottom of them. Pry gently an see if it gives at all.

[405driver]

Thanks, that's what I thought it was, didn't look like a button of any sort.

This is a new boat for us, had it about two months. Lots of little things that needed to be fixed. The front heat has never worked. I talked with the previous owner last night and he even replaced the circuit board ($700) and it still didn't work. Late last night I went into the menu and found that U-1 was set on "cool only". I changed it to "automatic" and the heat came on . I hate to tell him that it might have been a menu setting all along. Hard to believe that a technician wouldn't have known that. We'll see what happens.

Thanks for your input.

[PJHoffnet]

Looks like good research and a methodical trouble shooting approach saved you a lot of headache and money. One concern as I creep closer to being an owner is the availability of paper/electronic guides/owner's manuals on older, no longer produced, gear.

[405driver]

The internet is really amazing when it comes to finding manuals for ancient boat systems. When trying to figure out this A/C issue, I came across a Marine Air manual that had the diagnostic procedure in it. That test proved that nothing was wrong with the unit, which was a big relief. That test, is also not in the basic owners manual. I have found that usually someone else has had the problem that you are having an some posted something about it.

The internet and this forum has been a great help in this "old boat" project.

Jump in, the waters fine.....the research is really quite fun.

[Viper]

That's great news. Good find.