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Blower for engine

Printed From: myHanse.com
Category: General
Forum Name: Cruising
Forum Description: Chat about Cruising
URL: https://www.myhanse.com/forum_posts.asp?TID=13554
Printed Date: 12 April 2024 at 15:33
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: Blower for engine
Posted By: Ashtead
Subject: Blower for engine
Date Posted: 29 July 2022 at 12:29
hi - our engine blower on a Volvo 40hp seems to have packed up. Is there a fuse maybe which has gone and if so any thoughts on location?



Replies:
Posted By: Wild
Date Posted: 30 July 2022 at 19:11
model? Year?
The engine compartment blower is normally powered by a relay on the on-off switch of the engine contact
So if you donít have a wiring diagram try the following the wires of the blower to find the fuse.


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Wild and Wet
Belgium
545e#268


Posted By: Ashtead
Date Posted: 03 August 2022 at 19:58
hi we are a 2015 moody but built by Hanse so same Volvo set up maybe the relay has failed but I will investigate. It used to carry on running for a while after shut down of engine


Posted By: Mat
Date Posted: 17 October 2023 at 01:04
Hi, Iím on a Hanse 385 (2016) with a VP D1-30 and had encountered something similar where I thought my engine blower had given up. Motor and cooling worked perfectly fine, safe for the blower. My initial thought was something is wrong with the wiring or fuses but then I found out that the blower is actually not wired to the engine switch (at least not on my boat) but only turns on if you also have your service battery switched on concurrently. By way of reference, my blower draws about 6 amps.


Posted By: DJgun
Date Posted: 17 October 2023 at 01:39
An my 2007/2008 H400e, there was a blower which had seized. Strangely the wiring isn't even shown anywhere on the wiring diagram.  When I investigated by tracing wires I found the wires not terminated at the electrical panel end. Obviously the previous owner just disconnected it all when the blower failed.

I decided to put a timer relay on the blower, so it runs just for 5 minutes at engine start, and also 5 minutes at engine shut-down. 

Rather than use another axial blower I changed to a centrifugal blower which can handle bigger pressure differences  and is continuous rated not intermittent rated like most of the axial blowers. Reliability is important to me.


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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: Ratbasher
Date Posted: 17 October 2023 at 07:10
DJ - thanks; I hadnít realised that the axial type was intermittent rated.  Mine died at the start of the season and I replaced it with a more powerful Vetus for not much money more. Iíve had the boat for 600 of its 1600 engine hours so unsure if the blower had been replaced previously. In light of your comment Iím wondering if they should just be classed as a consumable item if you want to have them running continuously, as I understand they should be. 

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H400 (2008) 'Wight Leopard', Gosport UK


Posted By: Mat
Date Posted: 17 October 2023 at 07:59
Thatís a good one. I also thought the engine vent should be running as long as the motor is on. I guess the idea is to get any potential mono carbon dioxide out of the ship so if youíre sailing single handed and on deck with fresh air the 5 min in and 5 min out would possibly good enough for the one-man-band but if itís crew, I would think the blower should run all the time, no?


Posted By: H8jer
Date Posted: 17 October 2023 at 09:13
Hi 
I have a cheap attwood 3000 turbo fan.
Got it from svb, but their datasheet does not state anything about running it continuously.
But this English Chandler states both continuously and not... (in the Q&A section)
https://www.force4.co.uk/item/Attwood/Turbo-Bilge-Blower/TCR" rel="nofollow - https://www.force4.co.uk/item/Attwood/Turbo-Bilge-Blower/TCR
My 370 has an relay below the electric cabinet that powers the fan whenever the 'ignition' is on.
I would always have it running when the engine is running. The exhale from the fan is quite hot so it surely improves the temperature in the engine bay.

I have allready replaced the fan once (have just above 1000 engine hours with my 2008)
But from the thread I get it, that I perhaps should upgrade to a more sturdy and continuously rated fan.




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Hanse 370#487 30HP 3-cabin


Posted By: Wild
Date Posted: 17 October 2023 at 12:05
We still have the Hanse original ( 2010 and +2500 h) Jabsco 35400 100mm/12V
Running continuously and have a delay relay of a few minutes after switch off the engine ignition.
Not one problem so far.


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Wild and Wet
Belgium
545e#268


Posted By: DJgun
Date Posted: 17 October 2023 at 21:16
Hi Ratbasher,

I probably didn't word my post properly. There are some axial blowers which are continuous rated, but most of the cheaper types at chandlers are not.
Similarly some of the cheaper centrifugal blowers are intermittent rated. The published life of many blowers is shorter than I would like.

When the engine is running it actually sucks in significant amounts of air, including fumes in the engine room. For that reason I don't believe it is necessary to run the blower continuously, but if the blower is continuous rated it gives that option.

Running the blower before starting the engine is to ensure any combustible gases in the engine room are expelled before operating the starter motor,. Running after the engine is shut down is to remove any heat or fumes which may be created by the cooling engine.  The primary reason I changed to centrifugal is that it pumps higher volumes when there is back pressure due to the hoses etc.


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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: DJgun
Date Posted: 18 October 2023 at 00:35
Originally posted by Wild Wild wrote:

We still have the Hanse original ( 2010 and +2500 h) Jabsco 35400 100mm/12V
Running continuously and have a delay relay of a few minutes after switch off the engine ignition.
Not one problem so far.

Hi Wild,
The Jabsco 35400 is a centrifugal blower which I believe is the best option in this application. The manufacturer lists the maximum motor life as 1000 hours, so you have been very lucky if it is running already for 2500 hours. Nominally it is designed for intermittent duty.

Cheers, DJ


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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: Wild
Date Posted: 18 October 2023 at 07:26
Originally posted by DJgun DJgun wrote:

Hi Ratbasher,



When the engine is running it actually sucks in significant amounts of air, including fumes in the engine room. For that reason I don't believe it is necessary to run the blower continuously, but if the blower is continuous rated it gives that option.


I believe it Ďs the best running the blower continues when the engine is running.
The engine compartment in a boat is small and the engine need to suckís a lot of ,and best of all fresh clean air. In a car- our a 🏍 motor thatís not a problem on a sailboat engine compartment the natural fresh air flow is not very good.
On big motoryachts they used big heavy duty blowers with air intake gaps besides the boat.


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Wild and Wet
Belgium
545e#268


Posted By: DJgun
Date Posted: 04 November 2023 at 11:54
Hi Wild,
The problem with your suggestion is that the fan is sucking air out of the engine  room which is quite small on these boats. The fans are not blowing fresh air into the engine room.

The engine itself is a high flow air pump, which creates but better suction than any small axial air blower/fan, and transfers enough volume too. If the engine is running the electric fan proves nothing but a lower pressure in the engine room, and it is fighting the engine for air supply.

It could be that the engine running will increase rhe pressure drop across the electric fan enough to overload it electrically.


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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: Wild
Date Posted: 04 November 2023 at 15:29
Hello DJgun
Thereís no blower in the fresh air intake 100mm on the bottom of the engine compartment.
The Jabsco blower with 100 mm suction tube is at the top of the engine compartment.
So no obstruction for the engine air intake only continues fresh and cold air flow around the engine.IMO a good ventilation.
After a closer look we have the Jabsco 35770-0092 heavy duty-continues running instead the 35440


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Wild and Wet
Belgium
545e#268


Posted By: DJgun
Date Posted: 04 November 2023 at 23:05
Hi Wild,
That is an excellent blower you have, continuous rated. Interesting that you have 4" ducting. On my 400 ( l2007 build) I have only 3" duct, and only an extraction duct, no fresh air duct. There are various openings between engine room and the lazarette area which is where the engine draws it's air, as well as through the extraction duct in the reverse direction if the fan isn't running.

It looks like you have a generator tucked in the engine room too. Is that to power the 11 amp draw from the fan? 😉 Fisher-Panda?

I won't run my fan continuously as I see no need to it for the reasons I stated,  but if you want to run yours continuously that's fine too. I have seen the odd yacht which the OEM  has configured one fan blowing into the engine room, and another extracting air from it. I can't remember if they ran continuously or not.


Cheers
DJ


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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: alidal
Date Posted: 05 November 2023 at 08:28
On my H400 from 2010 there is no fan and it works too...



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Hanse 400#655


Posted By: sgrhma2
Date Posted: 05 November 2023 at 16:30
Iím the same my 2005 370 has no blower fan. The engine itself is an extremely high capacity air pump in itself and will shift vastly more air than all the blowers mentioned. 
Blowers were originally fitted to boats to clear fumes or dangerous vapours from gas appliances and petrol engines (which use to be all carburettor fuelled and off gassed at shut down) and the blower was run for a while to clear the bilges of potential explosive gases before starting the engine. This was done to minimise the risk of fire or explosion when activating the starter and the associated electrical spark risk. With the move away from inboard Petrol engines blowers were still fitted and then in general became a regulatory requirement. 
While not having one on my boat, I have considered fitting one as I still have gas onboard for cooking and a small amount of petrol. Having said that I feel it is more important to properly maintain the gas system and store the petrol correctly than go to the grief of fitting a blower. However if you already have a blower maintain it properly, but donít get hung up if it stops working, add it to the end of season maintenance list, but at all times look after your gas system and how you store any petrol onboard.

Simon 


Posted By: S&J
Date Posted: 06 November 2023 at 00:02
I think that the main purpose of the blower is to extract hot air and fumes and vent these at the stern rather than simply have them passively vent into the cockpit.  I don't think that it is required to facilitate the engine airflow.
On a previous Beneteau the engine compartment didn't have a blower and we got a distinct diesel smell from the vents either side of the companionway.  Installing a small blower resolved this.


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H458 #159 Primal Mediterranean cruising


Posted By: DJgun
Date Posted: 06 November 2023 at 00:52
The posts from various owners with different production year boats is very interesting.
From the various contributions  it appears that Hanse didn't even fit engine room fans in 2005, 2006, then fitted a fan in 2007/2008 but didn't include the fan in wiring schematics, and then a year or two after they stopped fitting them again.   In 2007 they used 3 inch fan and a single duct, but at some later stage it seems from posts they used 4 inch and two ducts. Clearly Hanse had trouble coming to a firm conclusion about what was needed.

I agree with previous two posts on a couple of points.
Firstly the fan should be run before starting the engine  to remove any combustible fumes which could ignite from starter motor/solenoid operation. Just a safety precaution.
Secondly running the fan immediately after stopping the engine to remove any hot air, diesel fumes etc. A matter of comfort.
During running the engine itself does create a slight under-pressure in the engine room as it is an effective pump,  which should prevent fumes and smells escaping into main cabin area. The fan is thus not necessary while the engine is running.  

While the engine is drawing in significant amounts of air, it is not as much as some might think. The 3JH4E Yanmar is just 1.6 litre, so at 2400 rpm it is only drawing 1920 litres of air per minute (67 cfm). A 3 inch Jabsco 36740 is nominally 150 cfm for comparison. As the engine room is less than 2 cubic metres the engine will effectively draw in all the engine room air in under 30 seconds  when running. The Jabsco will nominally do it in less than15 seconds.
My own personal opinion (as a retired engineer) is that a fan is a good idea, but that it only needs to run before starting and after stopping the engine. If you want to fit one then either axial flow or centrifugal fans will work, but a centrifugal offers superior characteristics for this application.

Cheers
DJ




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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: Wild
Date Posted: 06 November 2023 at 10:35
DJ gun
Our 2010 Engine is Yanmar 4JH4 HTE turbocharged 2 litre
Maybe thatís the reason ??



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Wild and Wet
Belgium
545e#268


Posted By: DJgun
Date Posted: 06 November 2023 at 21:03
Originally posted by Wild Wild wrote:

DJ gun
Our 2010 Engine is Yanmar 4JH4 HTE turbocharged 2 litre
Maybe thatís the reason ??

Hi Wild, 
Oh yeah!
For sure that would be an important factor.  2.5 times the power = 2.5 times the air flow. With the turbo there will be a lot more heat in the engine room too so air circulation is necessary. 



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DJ Sailor Ordinaire
HIN DE-HANJ0331J708


Posted By: Mark&Catherine
Date Posted: 28 November 2023 at 16:47
Our blower failed and I went to the chandlry to buy another and was asked do I want the intermittent rated one (fitted) or the continuous one.  The price difference was negligible so I fitted the continuous rated one from the same manufacturer, same size and everything.  For boats that cruise like us, some days we are on motor so the continuous one is just more sensible. 

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385 ubulukutu sail number GBR 3350L in Turkey and Greece with Mark and Catherine


Posted By: H8jer
Date Posted: 28 November 2023 at 17:24
Hi Mark

What brand and model did get?



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Hanse 370#487 30HP 3-cabin


Posted By: Borjebus
Date Posted: 27 February 2024 at 14:16
Hi HŲjer,
Could you please take a photo ot that relay. I am about to update 100% of the charging equipment/batteries and this means remove a lot of stuff below the electrical cabinet. I believe there is a relay that is not documented - Might be the one for the fan.


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BńSK, Hanse 370e #82 from 2006, Yanmar 3JH4E/SD50, 3-blade Flexofold, RMC(Lewmar) 185 Bowthruster, Vulcan 9, Simrad+B&G instruments


Posted By: H8jer
Date Posted: 27 February 2024 at 17:04
Hi
Follow the red arrow Smile




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Hanse 370#487 30HP 3-cabin



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