Generator blower on or off?

Have a 3.5 kW generator with sound shield with a blower plumbed to it located in the ER. Two switches on control panel, on/off (turns blower on) and start/stop. Question: does blower need to stay on the whole time gen is running? Boat manual does not reference the blower and generator manual is not clear on this. Generator engine has closed cooling system.

Our 16KW is interlocked to the blowers. Blowers need to be on to start it and the gen will shut down if the blowers are turned off.

I am sure you can have it disconnected but you would want to know why it is set that way before you do that. If your genset has blow-by having the out blowers on will make your life a lot more comfortable.

TBed said:

Have a 3.5 kW generator with sound shield with a blower plumbed to it located in the ER. Two switches on control panel, on/off (turns blower on) and start/stop. Question: does blower need to stay on the whole time gen is running? Boat manual does not reference the blower and generator manual is not clear on this. Generator engine has closed cooling system.

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Gas or diesel?

oscar said:

Gas or diesel?

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My question too.

If gas, after filling, open hatches and do a sniff check. Then turn your blowers on for a minimum of 4-5 minutes before starting.

Not required for diesel.

If there's a blower ducted right to the sound shield, especially on a diesel, it's probably for cooling. Many generator heads are air cooled, so some air exchange is needed.

Diesel. The reason for the inquiry is that I woke up on the hook last week to a depleted battery that could not crank the generator. I had battery load tested and it showed OK and after charging the gen started fine. I just checked and the generator will not start with the blower switch off but will continue to run if turned off after start up. The blower sucks air through slots in the shield and vents into the ER about 2 feet from the slots so it must be for cooling. I was thinking the blower may be drawing too much power from the generator battery even though the AC battery charger is on.

TBed said:

Diesel. The reason for the inquiry is that I woke up on the hook last week to a depleted battery that could not crank the generator. I had battery load tested and it showed OK and after charging the gen started fine. I just checked and the generator will not start with the blower switch off but will continue to run if turned off after start up. The blower sucks air through slots in the shield and vents into the ER about 2 feet from the slots so it must be for cooling. I was thinking the blower may be drawing too much power from the generator battery even though the AC battery charger is on.

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The genny should have been charging the battery while it was running?

Can you move the blower to the house bank?

Does it look like blower is and add-on, or does it look factory installed?

If gen was designed right, the gen head should have internal fans and soundbox should have vents placed so those fans move air in and out of the box.

Sometimes this is marginal cooling for the gen end, and the fan could be a good idea.

My ride has a 5kW NL diesel, and on a hot summer day after running the main engine to temp, then anchoring and running the gennie, it gets HOT down there!! So I have a blower that evacs the engine room through a venturi nozzle. It does help. My choice to run it or not.

You could wire it up so blower is tied to fuel solenoid. That way when ever unit is on, blower is on. Unit shuts down, blower shuts down.

I don’t think the blower could possibly be draw more power than the battery charger can supply. Is the blower huge?

I really don’t understand why you need a blower that pulls air into the gen housing and blows it back into the engine room. Once the generator is running it’s pulling huge amounts of air from the engine room and pushes it out through the exhaust.

HopCar said:

I don’t think the blower could possibly be draw more power than the battery charger can supply. Is the blower huge?

I really don’t understand why you need a blower that pulls air into the gen housing and blows it back into the engine room. Once the generator is running it’s pulling huge amounts of air from the engine room and pushes it out through the exhaust.

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It could be similar to my set up. I have blowers in and blowers out. The blowers out are on when the gen set is running. This circulates air in the ER, and evacuates heat and blow-by from the gen set.

TBed said:

Have a 3.5 kW generator with sound shield with a blower plumbed to it located in the ER. Two switches on control panel, on/off (turns blower on) and start/stop. Question: does blower need to stay on the whole time gen is running? Boat manual does not reference the blower and generator manual is not clear on this. Generator engine has closed cooling system.

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I am going to guess that you have a 3.5kw diesel nextgen based on your boat description in your profile. The 3.5 genny does not have the ability to charge the battery while running. There are 2 blowers, one for the engine room and one attached to the generator. I have found that during long trips while the engines are running and I am running the genny having the engine room blower on makes little difference. While at anchor I have never run the engine room blower, but I have never run the genny for several hours at a time. If I remember correctly Rgano replaced the blower assembly on his genny set up so perhaps he will chime in or you can shoot him a pm. All in all I don’t think it is necessary to run the engine room blower but I don’t think it would hurt either but on or off it should not affect the starting, running, or stopping of the genny. Unless someone wired it that way.

If the generator doesn't have an alternator or method of charging the generator battery, I would rectify that first. Something as simple as a 120 VAC to 12 VDC battery charger could solve both problems.

Ted

The blower for the generator sound enclosure is there to help cool the generator's electrical head - which is only air cooled - despite water cooling for the engine. Some oems used a dc blower running off the DC system (dudh??) and will run the battery down. Many have been changed to AC blowers running off the generator, not the batteries. Many have been removed all together. An AC blower Last longer and more hp per cubic inch. Most are vented overboard not back into the ER. Your 34 has the same set up as my 30 Pilot II. Mine was removed and the sound shield removed. Been looking at putting the sound shield back on (noise reduction) but will add an ac blower to keep it cooler. I think there is write up on the next gen web site.

My blower has a minor effect in lowering engine compartment temperature when wishing to enter the compartment when the engine has just turned off. That's my only interest in the blower, having a diesel engine. When the diesel operates, it brings in fresh air and exhausts the waste.

Two different blowers - main engine room blower and Generator sound housing blower.


The generator housing blower is for cooling the generator electric power head - most when the main engine is not running and there is little circulation the the ER.


The main engine room blowers are employed to remove any combustible fumes from the ER - and don't think because it's a diesel, you don't need to run them before cranking her up. Lower potential but not impossible.