Blower air flow for genset

[NEDBETTY]

Brain,
What is your opinion on not having a fresh air blower to our engine room on our 2014 CB31
It was not done or available FM says not needed.
I worry about the D3 Volvo and the Jenny (Cummins - Onan) all running at once in summer but they say don't worry it is not req.
I had planned to add Fresh Air Blower but did not.
Thanks Jeff

 

[Jfrano]

So thinking about two blowers and other options. Lack of space
For second blower is an issue.

I think What I’m starting to prefer, is letting air get pulled through gen front slats per NextGen and out top to
Port Side louver but rewiring Blower so it comes on it when the engine starts, so it constantly removing hot air. Genset slats are high in the engine compartment, so perfect location to remove hot air. Perhaps
Replacing existing blower with higher volume unit?

Thoughts ?

 

[CAPTCRUNCH]

That sounds like a good arrangement. Could you find room for a second blower if it were an in-line one instead of like the existing squirrel cage? Would you want to wire it so you can run it when the gen set is running but the engine is not?

 

[Jfrano]

Good points. Yes inline unit would be helpful.
Maybe one wired to generator and one to engine.
More to think about.

 

[BB marine]

Brain,
What is your opinion on not having a fresh air blower to our engine room on our 2014 CB31
It was not done or available FM says not needed.
I worry about the D3 Volvo and the Jenny (Cummins - Onan) all running at once in summer but they say don't worry it is not req.
I had planned to add Fresh Air Blower but did not.
Thanks Jeff

Jeff, I have posted my thoughts on this in a past thread. if you read through them you will understand my thoughts on this matter and why I disagree with the fluid motion thought process of

viewtopic.php?f=19&t=9924&start=0&hilit=ventilation

viewtopic.php?f=2&t=10314&hilit=ventilation#p71137

So thinking about two blowers and other options. Lack of space
For second blower is an issue.

I think What I’m starting to prefer, is letting air get pulled through gen front slats per NextGen and out top to
Port Side louver but rewiring Blower so it comes on it when the engine starts, so it constantly removing hot air. Genset slats are high in the engine compartment, so perfect location to remove hot air. Perhaps
Replacing existing blower with higher volume unit?

Thoughts ?

I would use the starboard ventilator to bring outside air into the sound box plus use the sound box louvers. I would use Trident hose . The flow is much better. I used the cheap stuff on my first install and found the Jabsco blower drawing almost 6 amps and moving very little air. After changing to the trident, the air movement increased and the amps dropped to 4 amps. The trident doesn't kink or crush. An additional blower will help. Two blowers used in my system will reduce the complete engine compartment temperature by 20+ F. If you decreased the generator box by 20 F there would be no need to install a higher amp fuse or breaker and you will also increase the longevity of the generator and it's components.

The manual for NexGen
https://www.google.com/url?sa=t&rct=j&q ... QKpsXxp4CB

Installation Manual for Volvo D4 and D6
https://www.google.com/url?sa=t&rct=j&q ... waAQEI8ktP

There is some good information in both of theses. I question if the technicians at Fluid Motion have ever read these. There are several questionable procedures that have not been followed with the installation of my engine in the C26. Read the ventilation section. There was nothing followed in that procedure.

 

[Jfrano]

So Trident hose is on the way $5.99 a foot, but it will be done right.

Will take starboard air intake to bottom/front of Genset housing; then from top
of Genset to blower and out blower to port exhaust vent.

I’ll do that work myself. I’d like to have the blower rewired to come on when either the engine OR the genset are running. Should that be feasible?

 

[CAPTCRUNCH]

I think you'll want to keep the genset control 12v dc circuit from backfeeding the engine circuit through the blower and vice versa. I'm no expert so don't rely on this, but I suspect a couple of diodes would do the trick. Maybe somebody who knows the answer will chime in.

 

[BB marine]

So Trident hose is on the way $5.99 a foot, but it will be done right.

Will take starboard air intake to bottom/front of Genset housing; then from top
of Genset to blower and out blower to port exhaust vent.

I’ll do that work myself. I’d like to have the blower rewired to come on when either the engine OR the genset are running. Should that be feasible?

Yes the trident is pricey but will last forever and better flow. I would not have auto start from the engine. This could cause issues in isolating battery circuits. I would keep the auto start blower from the generator. If you want to have the blower run when the Generator is not operating I would install a manual switch to manually turn the blower on but have it wired to the generator start battery. This switch would over ride the auto switch relay on the generator. Very simple wiring. 12 gauge wire with 10 amp inline fuse coming from the generator battery to a 10 amp switch ,12 gauge wire from the switch to the blower. The wire would be spliced at the positive blower connection with the generator auto connection. The wiring would be the same as auto/manual bilge pump wiring schematic. Install a switch in the cockpit. Photo below shows my switch location for my two blowers.

gallery2.php?g2_itemId=51951

 

[Jfrano]

Yes , rehashing this one. Hope to actually complete reventing this week.

Does anyone have images or can explain how the vent hose reaches the port side vent louvre...I’m not seeing the path?

 

[BB marine]

Brain,
What is your opinion on not having a fresh air blower to our engine room on our 2014 CB31
It was not done or available FM says not needed.
I worry about the D3 Volvo and the Jenny (Cummins - Onan) all running at once in summer but they say don't worry it is not req.
I had planned to add Fresh Air Blower but did not.
Thanks Jeff

Jeff, I have posted my thoughts on this in a past thread. if you read through them you will understand my thoughts on this matter and why I disagree with the fluid motion thought process of

viewtopic.php?f=19&t=9924&start=0&hilit=ventilation

viewtopic.php?f=2&t=10314&hilit=ventilation#p71137

So thinking about two blowers and other options. Lack of space
For second blower is an issue.

I think What I’m starting to prefer, is letting air get pulled through gen front slats per NextGen and out top to
Port Side louver but rewiring Blower so it comes on it when the engine starts, so it constantly removing hot air. Genset slats are high in the engine compartment, so perfect location to remove hot air. Perhaps
Replacing existing blower with higher volume unit?

Thoughts ?

I would use the starboard ventilator to bring outside air into the sound box plus use the sound box louvers. I would use Trident hose . The flow is much better. I used the cheap stuff on my first install and found the Jabsco blower drawing almost 6 amps and moving very little air. After changing to the trident, the air movement increased and the amps dropped to 4 amps. The trident doesn't kink or crush. An additional blower will help. Two blowers used in my system will reduce the complete engine compartment temperature by 20+ F. If you decreased the generator box by 20 F there would be no need to install a higher amp fuse or breaker and you will also increase the longevity of the generator and it's components.

The manual for NexGen
https://www.google.com/url?sa=t&rct=j&q ... QKpsXxp4CB

Installation Manual for Volvo D4 and D6
https://www.google.com/url?sa=t&rct=j&q ... waAQEI8ktP

There is some good information in both of theses. I question if the technicians at Fluid Motion have ever read these. There are several questionable procedures that have not been followed with the installation of my engine in the C26. Read the ventilation section. There was nothing followed in that procedure.

If you read the post's in this thread you will get your answer. The image you are looking for is right in the engine compartment of your boat. The access is tight after the boat is built. It is an easy install as the boat is being built. I know ! I spent hours routing the trident hoses in my boat to get them from the compartment to the hull vents.
I was on board a R29 just like your boat that had improperly installed ventilation for the GenSet. In fact every R29 that I have boarded and looked at the install has been done incorrectly (2019 or older) This is not to say the installs are correct in newer R29's. I just have not boarded and looked. When boarding and looking at the routing and blower location as found. I determined the best way to install a proper functioning vent system would be to install a vent hose to the starboard hull vent. This hose would go to the bottom of the sound box. Attach a hose to the top of the box. This hose will go to the blower suction side ( you will need to move the blower for better hose routing and there is room to do that) The exhaust side of the blower will have a hose attached to it that goes to the port vent. I would remove the vent from the hull to make it easier to bring the hose up into place. It is tight but it can be done.

I am amazed at how many of these R29 are using the generator in this model with this vent system installed backwards or not at all. I have looked into the storage lockers below the deck and the engine compartments in theses boats that are less then 5 years old and found mold, evidence of wet wood, soot from the engine exhaust, odor, and summing it up to a damp environment because of lack of ventilation. Then add the element of (this is a machinery compartment) Machinery generates energy, energy generates heat, heat is a product of energy and needs to be removed from the compartment for proper operation of the machinery. If it is not the machinery will not operate to its optimum design. Every generator or marine engine manufacture has a ventilation specification for their product. This specification is located in the manual for installation. It is there for a reason.

 

[Jfrano]

Would it be easier to follow the route of the old vent, by tapping the new hose to the cut end of the old and pulling it through the port or starboard louver, until the Trident hose appears?

 

[BB marine]

Would it be easier to follow the route of the old vent, by tapping the new hose to the cut end of the old and pulling it through the port or starboard louver, until the Trident hose appears?

You could try that. If the old vent hose is still in place. I would use a electricians fish tape (non conductive) fishing it through the original vent hose. Attach the tape to the new hose and use that for your pull. It would be best to have 2 people, one feeding the hose and one pulling to the hull vent location. It is only an arms length of a pull. Completely doable.

 

[Jfrano]

Hi,

Any ideas...Spending hours trying to connect blue
Vent tubing to the starboard louver.
Two ways- pull the tube through the hole
Out The exterior of the boat, tape the tubing to the louver and try to push back into boat. Seems too tight to push back in, shreds the tubing.
Second - mount the louver and from the inside put the tubing onto the louver flange . Boat Doesn’t seem to allow for the correct angle the get tubing onto the flange. I have a ss ring on the tube ready to slide
Over the tubing if I could ever get the tubing in place .
All I have to show after hours of work, is a smashed
Louver and cut up hands.

I had lined someone up in the off season. Their
All too busy on big ticket items for all the new boat owners to deal with this
Minor stuff!

 

[BB marine]

There are many times that access panels need to be installed when installing equipment after the boat is built. Or getting to a component after the boat is built. The vent and hose in the R29 was installed before the cockpit liner was set. When I installed my vent hoses and vents it required removing panels and cutting holes to gain access. This needs thought. It must not be done in any structural areas and must be done so that after the install a Beckson plate can be installed.

example: https://www.googleadservices.com/pagead ... RBk&adurl=

Would use a 4" if that can be used in the area of the vent.

The other thing that I would change is the vent itself. It sounds that the one that was there broke any way. I don't like those cheap plastic lover vents that Fluid motion uses. A high quality boat with cheap runabout vents!!

I used stainless steal vents with 90 degree elbows. This eliminates the need to kink the hose at the vent location because of tight tolerances.

Example: https://www.google.com/aclk?sa=L&ai=DCh ... ggQ&adurl=
https://www.defender.com/ProductDisplay ... id=2071546

When installing this you must have a plan, measure the working area and use parts that will fit in the area of the repair or retrofit.

The install that I did in my boat to improve the ventilation in the engine compartment was not bad to install after I made a plan. Making the plan and figuring out how I was going to get vent hoses from the compartment to the exterior of the boat was what took time. It can be done and it is a lot easier once you dig into it.

Below is a link to my install you will see it was not "plug and play " the end results was favorable and worth the time. I agree with your frustration you should not have to do this work on a newer boat.

gallery2.php?g2_itemId=51750

Good luck with your project.

 

[shark86]

I hope someone is still monitoring this thread because I have the NextGen overheat issue to fix.

Our new to us 2017 C28 has the NextGen (<10 hours on the meter) and it is tripping the breaker in warm weather even in the morning. After reading this thread, I determined the blower was connected incorrectly and was blowing air into the generator compartment instead of exhausting. Changed the direction of airflow and helped some. But, as Brian said, the exhaust is now going directly into the below deck compartment. I plan to install the Trident hose to improve the airflow, but don't know where to exhaust the air from the blower since the C28 does not have any existing louvers for the generator. It appears there is sufficient space to put in a louver near the Pumpout port by cutting a hole in the sidewall. Has anyone else undertaken installing a vent on the C28, and if so, where did you put it?

Thanks.

 

[it4llc]

Mark - I'm not sure if you are intending to do this work because your generator is still overheating or as an additional precaution. If the former, we had issues with our very low hour NextGen overheating as well on our 2020 C28. It turned out to be the impeller on the water pump needing replacing. I think we had around 15-20 hours on the generator. Once I figured out how to access the impeller, the repair was fairly easy, other than the contortions required.

The advice given to me by our mechanic when I was chatting with him while he was doing some other maintenance was to run the generator regularly, and that contrary to what you might think, a low hour generator on an older boat is not necessarily a good thing because lack of use can cause these types of issues.

 

[BB marine]

Mark - I'm not sure if you are intending to do this work because your generator is still overheating or as an additional precaution. If the former, we had issues with our very low hour NextGen overheating as well on our 2020 C28. It turned out to be the impeller on the water pump needing replacing. I think we had around 15-20 hours on the generator. Once I figured out how to access the impeller, the repair was fairly easy, other than the contortions required.

The advice given to me by our mechanic when I was chatting with him while he was doing some other maintenance was to run the generator regularly, and that contrary to what you might think, a low hour generator on an older boat is not necessarily a good thing because lack of use can cause these types of issues.

Two completely different problems. Your engine was over heating because of an impeller issue and an engine over heat. The subject of this thread is engine compartment ventilation and sound shield improperly ventilated. This doesn’t cause an engine over heat it causes the breaker to trip because the elevated air temperature decreases the the breaker’s capacity. The higher the air temperature the lower the breakers amp capacity is. This happens in areas with higher air temperatures. Probably not a problem in the PNW. In areas that water temperatures hit 80F and Air temperatures hit 80+ it does. Many Band aid the issue by installing a higher set breaker. The best solution is to pull outside air into the Generator and exhaust the air outside the engine compartment. This is known as engine compartment ventilation. A common practice throughout the marine industry.

To answer the question to the previous post. Take a look at my photo album. I installed vents in the cockpit, side of my hull, and the port side fake vents. I installed a manifold. This was used to exhaust the hot air out of the engine compartment. I lowered the compartment temperature by 30 to 40F when cruising in the Midwest and Florida. If you attachthe exhaust hose from the sound shield to any installed through hull vent you will not have any more issues. I know of a few C28 owners that used one of the cup holders in the cockpit to install a vent so they didn’t have to cut a hole. After they did this the breaker trip went away.

 

[shark86]

Brian,

You hit it directly on the head. I do not want to go the higher breaker route. That is not a good idea in my book.

I was thinking a cowl type vent in the side of the hull, but the thought of cutting a new hole makes my wife cringe.

Cockpit cupholder did not even come to mind. I will have to see how to make that work. Hopefully, just some extra Trident hose.

Thanks.

 

[dbsea]

I've wondered about this for my D6-435 as well, as I don't see any sort of fresh air ventilation into the engine compartment. Is that actually the case, or am I missing something? That seems preposterous...

 

[BB marine]

I've wondered about this for my D6-435 as well, as I don't see any sort of fresh air ventilation into the engine compartment. Is that actually the case, or am I missing something? That seems preposterous...

That was my thoughts too back in 2017 when I made a trip in my boat and found that the compartment temperature exceeded 160F where my engine air intake was located. My alternator was operating over 200F and my waste tank with waste in it was at 140 F causing a bad odor in the bilge. I thought that the vent hoses were restricted. When I checked the vent hoses I found that there were none. I have started many threads about this. The only ventilation is the air gaps between the cockpit liner and the hull. Basically the engine is the exhaust blower. I was on board a R29 that the engine was starving for air. The drain through hulls at the transom were pulling air into the compartment. Unfortunately the exhaust from the engine was being pulled in too. There was soot all around the hatch trough drains. Poor design, maybe that’s why they are building boats with outboards!! :shock: