Dickenson Newport "A permanently open fresh air inlet MUST be installed or dedicated"

[rognvald]

Zboss,
The bottom line is that there are many ways to skin a cat. But, it's your boat: Is "good enough"---good enough?

[zboss]

So, do you leave the heater running when you are sleeping? I have installed a CO2 detector.

[rognvald]

Originally Posted by zboss

So, do you leave the heater running when you are sleeping? I have installed a CO2 detector.

Zboss,
When you have spent such a considerable amount of time and money in the installation, should not safety and proper installation be your primary concern. A CO2 detector is a good backup, but do you want to go to sleep every night worrying? A safe and efficient system can be left running 24 hours a day as is the testament of thousands of commercial fishermen and high latitude sailors who rely on these units for heat and cooking. Its like running your engine with a disintegrating drive belt and relying on the engine alarm to signal its failure. A little extra effort and thought will pay countless dividends in the operation and security you feel when you operate your heater. Good luck and good sailing.

[zboss]

Originally Posted by rognvald

Zboss,
When you have spent such a considerable amount of time and money in the installation, should not safety and proper installation be your primary concern. A CO2 detector is a good backup, but do you want to go to sleep every night worrying? A safe and efficient system can be left running 24 hours a day as is the testament of thousands of commercial fishermen and high latitude sailors who rely on these units for heat and cooking. Its like running your engine with a disintegrating drive belt and relying on the engine alarm to signal its failure. A little extra effort and thought will pay countless dividends in the operation and security you feel when you operate your heater. Good luck and good sailing.

Hi, thats not really what I was asking, but I appreciate the response.

I fail to see how adding another 3" hole in my boat is beneficial.

[roverhi]

Actually, the hole for the stove flue is more like 5" so there is some insulation/separation of the pipe from the deck. A fresh air pipe only requires a 3" hole for the pipe to pass through.

[zboss]

Originally Posted by roverhi

Actually, the hole for the stove flue is more like 5" so there is some insulation/separation of the pipe from the deck. A fresh air pipe only requires a 3" hole for the pipe to pass through.

Yea, I just got my heater in from Defender today. I'm working with Phipps Boat works here in Herrington to help me drill the 5" hole and build a nice teak surround for the chimney mount. Its basically enlarging an existing (previous used) chimney hole.

Oddly, I was not able to find anybody in the immediate area to actually complete the install. I guess the margins on $1000 device is a lot lower than selling a $5500 forced air or full on air conditioning.

[DSDman]

Zboss. I would like to come by and see the install sometime if you would let me. I've been thinking about doing the same thing since at some point my cruising grounds will include points north and my reverse cycle units will only do so much.

[zboss]

Originally Posted by DSDman

Zboss. I would like to come by and see the install sometime if you would let me. I've been thinking about doing the same thing since at some point my cruising grounds will include points north and my reverse cycle units will only do so much.

You are more than welcome to. I am sitting here now with the winds blowing outside. Even on the lowest heat setting, the upper half of the boat is 80 degrees.

I've decided you really need an input airflow and an output airflow in addition to the chimney. I have two dorades, but one is closed because it is next to the chimney of the stack. The second one is forward of the dining area in the head.

When its just that open you can barely feel the airflow but when I open a porthole towards the stern you can feel the breeze coming down the dorade from two feet away. It doesn't seem to negatively affect the heating!

[FlyingCloud1937]

Originally Posted by zboss

Does an dorade count as a "A permanently open fresh air inlet" for a Newport Diesel Heater?

- z

The Answer is typically no.

Unless it facing the wind. Usually they are aft facing and are counter productive. As in that position they act as a convection chimney (heat rises). And will starve the pot of oxygen.

An oil stove is a drip pot burner, that relies on draft from the convection of the heat rising through the stack, to intake combustion air into the burner.

So any additional convection losses by a dorade just starve the stove of the oxygen required for an efficient burn of the fuel in the pot.

A barometric dampener is not going to stop the stove from the dreaded back draft that fills the cabin with unburnt oil/carbon/fumes. The job of a barometric dampener is to stop the stove from running to lean.

A drip pot/draft burner needs to run in balance, much like an external combustion engine. It can't run to rich, nor can it run to lean.

When running lean you risk the dreaded downdraft, when running to rich you risk the dreaded tar and soot spewing from the stack as well as the dreaded down draft.

So that's why they are called balanced draft burners.

You must supply the stove with intake air(oxygen) that is not subject to convection/drafting or other negative losses from windage.

Ideally the air intake should be vented from both sides of the boat, and not subject to wind direction. One forward and one aft.

Lloyd

[Panope]

Originally Posted by FlyingCloud1937

The Answer is typically no.

Unless it facing the wind. Usually they are aft facing and are counter productive. As in that position they act as a convection chimney (heat rises). And will starve the pot of oxygen.

An oil stove is a drip pot burner, that relies on draft from the convection of the heat rising through the stack, to intake combustion air into the burner.

So any additional convection losses by a dorade just starve the stove of the oxygen required for an efficient burn of the fuel in the pot.

A barometric dampener is not going to stop the stove from the dreaded back draft that fills the cabin with unburnt oil/carbon/fumes. The job of a barometric dampener is to stop the stove from running to lean.

A drip pot/draft burner needs to run in balance, much like an external combustion engine. It can't run to rich, nor can it run to lean.

When running lean you risk the dreaded downdraft, when running to rich you risk the dreaded tar and soot spewing from the stack as well as the dreaded down draft.

So that's why they are called balanced draft burners.

You must supply the stove with intake air(oxygen) that is not subject to convection/drafting or other negative losses from windage.

Ideally the air intake should be vented from both sides of the boat, and not subject to wind direction. One forward and one aft.

Lloyd

I am no expert on these stoves but this is the best short explanation about their combustion process that I have read. It explains to me (finnaly) why my stove has never had the dreaded down draft. The air intake is via my main companionway sliding hatch. I built the hatch with a gap of about 1/2 inch around the perimeter. It appears that no matter what direction the wind is blowing it never produces a negative pressure. The boat does not have any dorades.

Steve

[sailorchic34]

Originally Posted by FlyingCloud1937

The Answer is typically no.

Unless it facing the wind. Usually they are aft facing and are counter productive. As in that position they act as a convection chimney (heat rises). And will starve the pot of oxygen.

A barometric dampener is not going to stop the stove from the dreaded back draft that fills the cabin with unburnt oil/carbon/fumes. The job of a barometric dampener is to stop the stove from running to lean.

Not exactly...

While it is true that hot air will rise and will vent from a dorade, There has to be balanced air flow, that is outside air must replace the hot air exiting the dorade from somewhere else, mostly likely a different dorade vent.

Most boats have two or four dorade vents. Me I like to have at least once forward and one aft, so when I'm swinging on the tide, I have one into the wind and at least one other away from the wind.

Actually a Barometric damper is used to balance air flow due to changes in atmospheric pressure and its installation promotes an even draft, that is it assists in promoting a balanced negative draft up the flue and balance the air flow at the burner.

Not having one could cause the flue gas to not vent under all atmospheric conditions or vent to fast. which would make the combustion mix rich or lean.

Sorry, I still feel that a Dorade vent provides a clear opening into the hull. Its a totally non issue with two or four vents. The intent of the requirement is to allow for the replacement of air and to balance inside and outside atmospheric pressure.

Dorade vents do just that...