Vbirth heat no worky

[Steve91T]

AC works great. Heat has never worked. Fan kicks on like it wants to do its job and make heat but it won’t kick the compressor on. I feel like something isn’t hooked up that should be. I also feel like it’s something extremely simple which will be a royal PITA to figure out.

Here are some pics to help.

Thanks all.

 

[rgano]

Who ate my shrimp?

It is likely you will need somebody who speaks AC, specifically things like reversing valves. I didn't stay in a Holiday Inn last night and am this useless.

 

[FF]

Just because you have controls that show the ability to create heat does not mean the unit is capable of heating.

A tech will be required , yes to look for reversing valves , to decide what you have installed.

 

[O C Diver]

Not all units with heat do it with reverse cycle, some just use a heat coil. There may be an option in the menu to activate beyond just selecting heat.

Ted

 

[Turtle Blues]

Picture 2 looks like an encased blower? Does it have an electric heat coil
Rather than using the AC reverse cycle I have Hot Pods in the supply duct that look similar.

 

[bayview]

Yes look for the reversing valve on the compressor. Sometimes just rapping it with a tool will loosen it if it hasn't been used often.

 

[Comodave]

Do you have the make and model number? If so I would call the manufacturer and see if it actually does have heat, a lot of A/C units are cool only. Just because the thermostat has a heat setting doesn’t mean the unit has heat capability. If it does have heat what type of heat does it have? Reverse cycle or resistance heat. If it has reverse cycle the reversing valve could be bad. If it is resistance heat the element could be burned out. First thing is you have to know what type of unit you have. Good luck.

 

[Steve91T]

Thanks guys. I really don’t like to just call a mechanic without having an idea of the problem first. Been screwed over before. Plus it’s a way for me to learn more about the systems of the boat.

There are 3 reverse cycle systems on the boat and I find it hard to believe that the forward system would be the only one without heat.

I pulled off the duct and inside the white plastic thing is simply a T off the blower to send air to the left and to the right. One blows into the v birth the other blows into the galley. I didn’t see signs of electric elements.

Does anyone have a picture of a reversing valve? Any more information on how it works? Is it a simple valve that reverses the water flow? The fact that the compressor isn’t kicking on when calling for heat is interesting as well.

This system is in a tight closet so I’ll have to pull the ducts out and the blower duct to see anything.

I need to make another trip to the boat soon....I’m craving more shrimp and grits

 

[Comodave]

I am not an A/C expert but the reversing valve reverses the coolant flow so instead of dumping heat into the cooling water it takes heat out of the water and brings it into the boat. The water flow doesn’t change at all.

 

[Steve91T]

Ok thanks. My central system is easy to get to so I’ll try to find it on that system first so I know what I’m looking for.

In the mean time if anyone has any more info I’d appreciate it

Thank you.

 

[OldDan1943]

Steve, you will not see a heating element on a reverse cycle A/C unit.
It makes heat via the reversing valve. It then takes heat out of the water instead of putting heat into the water. You should be able to hear the reversing valve click as it changes from A/C to heat position.

You also mentioned a T in the blower outlet. They do make an adjustable Y fitting so you can set the amount of the blower air going fwd. It may be a bit involved to install it and personally, if I wanted/needed that, I would let the tech install it. It is a 'set and forget' and not meant to be changed frequently.

The unit that supplies the fwd stateroom and galley, .... is the thermostat located in the fwd stateroom? If not, you will need to adjust the temp so you get more heat fwd and may make it uncomfortable in the galley area.

Just for fun, use an IR gun to measure the temp of the air coming into the fwd stateroom compared to the temp of the air coming into the galley area. They should be reasonable close in temp.

Assuming the reversing valve works, I would start trying to increase the airflow into the fwd stateroom.

If all else fails, a nice 120vt ceramic heater will solve your lack of heat problem.
I too suffer from reduced airflow into my stateroom. The American Tugs have a built in 120vt resistance heater that solves the lack of heat in that stateroom.
As per the lack of ideal temp in the summer time, I am considering an awning over the 'house', when I am in port. I have been considering it for about 5 years.

 

[bayview]

Do a web search for marine air revising valve. lots of info there.

 

[Steve91T]

Thanks everyone.

To answer some questions. All 3 systems are all tied into each other. Durning the summer, all 3 systems worth together to keep the boat cool. For a while we had the forward system not working. It was just tripped due to a dirty strainer, it during that time, the art and central systems couldn’t keep up and it would be 90 degrees. With all 3 running, it can maintain 80 and recover much quicker. It’s very comfortable and even in the summer it’ll freeze you out at night.

So I like the plumbing. During mild weather, the central system is really the only one that runs due to the fact that it gets the sun through the windows.

Anyway, back to the forward V birth heat....I did some reading on the reversing valve. From what I read, it sounds like if the reversing valve was stuck, the compressor would still run, you just wouldn’t get hot air.

Mine doesn’t kick on. The fan does, just not the compressor.

So next time I’m at the boat, I’ll take the ducts apart so I can see and I’ll look for a reversing valve. I’m hoping it’s there and there’s just a wiring issue. But you guys might be right, it might not be a model that provides heat.

We’ll see. If it doesn’t, I’m not too worried. We can just leave her door open and crank the heat in the saloon.

Thanks everyone.

 

[OldDan1943]

The reversing valve is exterior to the duct work.
It is time for you to get a tech out there to show you around the A/C unit?

 

[Steve91T]

The reversing valve is exterior to the duct work.
It is time for you to get a tech out there to show you around the A/C unit?

Because the system is in a closet, a small one, the duct work makes it very difficult to really be able to see anything at all. So removing it will give me better access to the system. In that 2nd picture I posted, the unit sits behind the ducts and that white blower T.

I’m just going to take a look. Should be able to find out a lot. I might end up needing a tech, but it doesn’t hurt to do some digging first.

 

[Rufus]

It helps if you have a schematic of the system. Our CruisAir units have one inside the cover of the control modules...and I have a manual. Dometic's tech hotline is very helpful if you have any of their legacy units....MarineAir and CruiseAir, for example.

 

[stubones99]

https://www.amazon.com/Fdit-Conditioning-Reversing-Refrigeration-Maintenance/dp/B07SJ7J7X2
This may look like yours, if you have a heat-pump A/C unit.
Even a heat pump A/C system will have a heater element for heating if the incoming water is below 38 degrees F, since pulling in cold water and removing more heat makes it an icemaker, which often splits the heat exchanger and other fun / expensive things.

Be careful rapping on any brass or bronze metal parts since A: they hold a liquid or gas inside, and B: Brass and Bronze are quite soft metals and don't like getting hammered on.

 

[oscar]

Well, if a V-birth is not working you need to try a Cesarean.

 

[stone beach]

Did you try it on cooling just now? and the compressor and fan do what they are supposed to on "cool" right? if yes you know the compressor is working. I know you said AC works great but maybe that was some time ago.

Next a really simple thing you must have tried already?? but you don't mention so here goes.
After you start the unit on "heat" and the fan starts but not the compressor.... did you turn up the demand temperature on the control as far as it will go? and the cabin is below that temperature right? Also it generally takes a few minutes to start on its reverse cycle, you did give it a few minutes?

Can you see the cooling water overboard discharge from this unit? is water running out?

Even if you cant see the discharge, if you have multiple units but only one sea water pump you should be able to hear the water running through the problem unit after you have started one of the other units.

No water is what usually stops the compressor (correctly) via the high pressure cut out... but typically that stops it after it has run dry for a short while, if the compressor
isn't cutting in on cold or hot maybe the high pressure cut out stopped it last time it was in use and you need to reset it, there is little tab to press back in

 

[Steve91T]

Did you try it on cooling just now? and the compressor and fan do what they are supposed to on "cool" right? if yes you know the compressor is working. I know you said AC works great but maybe that was some time ago.

Next a really simple thing you must have tried already?? but you don't mention so here goes.
After you start the unit on "heat" and the fan starts but not the compressor.... did you turn up the demand temperature on the control as far as it will go? and the cabin is below that temperature right? Also it generally takes a few minutes to start on its reverse cycle, you did give it a few minutes?

Can you see the cooling water overboard discharge from this unit? is water running out?

Even if you cant see the discharge, if you have multiple units but only one sea water pump you should be able to hear the water running through the problem unit after you have started one of the other units.

No water is what usually stops the compressor (correctly) via the high pressure cut out... but typically that stops it after it has run dry for a short while, if the compressor
isn't cutting in on cold or hot maybe the high pressure cut out stopped it last time it was in use and you need to reset it, there is little tab to press back in

Yep, AC was working great that day. This thing hasn’t had heat since we’ve had the boat for about 2 years. Ac has always worked.

Yes, setting the heat to a temp higher than ambient will kick on the fan but that’s it. No pump, no compressor. This unit has its own pump and it has excellent flow, when it is on.

So like I said, AC works as it should. When I select heat and the temp falls below the set temp, or I set a higher temp, the fan will kick on (auto mode) but it doesn’t turn the pump on or the compressor.

I believe if it was just a bad reversing valve, the pump and compressor would turn on but I wouldn’t get heat.

So my thoughts are, either something isn’t wired properly or this system is AC only. Being that this has always been a Florida boat, that might be the case. Maybe whoever had these installed never used the v birth and didn’t want to spend the extra money. Idk.

But if I remove the ducts so I can see inside and look for the reversing valve, that should tell me what I need to know. Then I can go from there.

That’s why I don’t think an ac tech is necessary.

 

[OldDan1943]

I am in an area between Hollywood and Miami FL. Trust me, you do need heat.
There are days I have to wear long pants and on a really cold day, socks too.
Life is good. 10am, sunny and 74F.

 

[OldDan1943]

..... I believe if it was just a bad reversing valve, the pump and compressor would turn on but I wouldn’t get heat.

So my thoughts are, either something isn’t wired properly or this system is AC only.

But if I remove the ducts so I can see inside and look for the reversing valve, that should tell me what I need to know. Then I can go from there.

That’s why I don’t think an ac tech is necessary.

If you discover you do not have a reversing valve, I think buy a ceramic space heater would be less expensive and perhaps better because you can move the heater to the saloon or the other stateroom as necessary.

Of course, you could just add a couple of blankets to the bed like I do.
Now, if I could warm the sheets before bed time and perhaps more importantly, warm the toilet seat.

 

[stone beach]

Yep, AC was working great that day. This thing hasn’t had heat since we’ve had the boat for about 2 years. Ac has always worked.

Yes, setting the heat to a temp higher than ambient will kick on the fan but that’s it. No pump, no compressor. This unit has its own pump and it has excellent flow, when it is on.

So like I said, AC works as it should. When I select heat and the temp falls below the set temp, or I set a higher temp, the fan will kick on (auto mode) but it doesn’t turn the pump on or the compressor.

I believe if it was just a bad reversing valve, the pump and compressor would turn on but I wouldn’t get heat.

So my thoughts are, either something isn’t wired properly or this system is AC only. Being that this has always been a Florida boat, that might be the case. Maybe whoever had these installed never used the v birth and didn’t want to spend the extra money. Idk.

But if I remove the ducts so I can see inside and look for the reversing valve, that should tell me what I need to know. Then I can go from there.

That’s why I don’t think an ac tech is necessary.

I doubt this is a reversing valve problem, the simple control system wouldn't know about that, the compressor would start with the fan and blow cold if the reversing valve was not working. I think you just have a cooling unit

 

[Steve91T]

I doubt this is a reversing valve problem, the simple control system wouldn't know about that, the compressor would start with the fan and blow cold if the reversing valve was not working. I think you just have a cooling unit

I agree. Although I’m hopeful that it just isn’t wired properly. Whatever wires send the signals for heat. But I honestly doubt it. And one other thing, the PO had a bunch of little fans throughout the boat which are nice in the summer to help move the air around. The v birth is the only place where we found a little table top heating fan.

 

[Steve91T]

I am in an area between Hollywood and Miami FL. Trust me, you do need heat.
There are days I have to wear long pants and on a really cold day, socks too.
Life is good. 10am, sunny and 74F.

It’s not a huge deal. The rear and central units do have heat and work well. We never bothered with the heat up front because we didn’t use the v birth but now the kids are a little bigger and our 6 year old has moved to the v birth and our 2 year old into the mid cabin. So she’ll need something. But just leaving her door open to the rest of the boat will be enough. Plus there’s that little space heater fan that helps.

The boat is in southern GA now. It gets cold but nothing that the other 2 systems can’t deal with.

Summer is another story. All 3 systems need to be working to keep up. We had the forward system trip and it got hot fast.

 

[Northern Spy]

The simplest thing might be to check the wiring to the thermostat. Is it 2 wire or 3 wire?

If it is 3 wire, is it terminated properly?

 

[Steve91T]

The simplest thing might be to check the wiring to the thermostat. Is it 2 wire or 3 wire?

If it is 3 wire, is it terminated properly?

Didn’t have time last night to mess with the front heat but I did get a pic of the wires going to the thermostat. 4 wire it looks like. Does that mean anything?

 

[Ski in NC]

Good chance they installed a simple AC system and there is no reversing valve for heat. Costs less and not really needed in a Fla boat.

If you could get to easily view the whole unit, it would be obvious if reversing valve existed. Since it is tucked away tight, best thing is to get the model number and do a little recon.

Post model and make and we might do the recon for you.

 

[SteveK]

Well, if a V-birth is not working you need to try a Cesarean.

The simplest thing might be to check the wiring to the thermostat. Is it 2 wire or 3 wire?

If it is 3 wire, is it terminated properly?

Two really good answers

 

[Steve91T]

Forgot the pic apparently.

Anyway like I said I didn’t have a chance to take things apart to get to the compressor.

I’ll do that the next trip.