Revised Bilge Blower Discussion

[paulr]

I had my Carver 396 (gas) for 2 years now and the blowers have never worked correctly. I replaced all 4 blowers and the 4 relays and only 1 blower works.
The owners manual that came with the boat has a wiring diagram and it doesn't even show the 4 relays that are installed next to the blowers in the bilge.
I called 2 highly rated ( 5 star) mobile marine repairs services and was shocked to here they will not service Carver blowers.
What I would like to do is to simply have the switch on the bridge or the switch on the main DC breaker panel turn on all 4 blowers at the same time.
I have read all the articles on this forum on this subject and it seams there is a significant amount of confusion on how these blowers are meant to work.
Does any have experience changing the blowers to a more simple logical control system?
Thank you for any help.

[g36]

I don't know your specific boat. Do you have a meter or just assuming to and guessing everything is wired correctly and its not been tickered with?. But using a volt meter should be easy to determine where you are losing voltage. If there's supposed to be relays in line they may not be wired correctly. If one is working you should be able to copy that setup for the others. The carver schematics on my 405 don't really do alot but they are what they are. Yours probably the same.

[paulr]

Thanks for the reply, I'm going back to the boat Friday to check things all over again.

[paulr]

Problem solved: To start, because the age of the boat 3 blowers were making a grinding noise and (1) was burned out. I replaced all 4 blowers. Then 3 blowers would run. There was burned out 5 amp inline fuse and (1) open ground wire.
I am not sure about this, of the (2) blowers on each side, should (1) blower blow in and (1) blow out?
Or should (2) blowers blow "in" on the port side and (2) suck out on the starboard side?

[Carverlvr2]

One side should suck the other side should blow. Otherwise one blower could be pulling back in the fumes the other right next to it just blew out. I’ll double check on my 366 but I think I only have one blower on each side. Can’t imagine why the 396 with Same 8.1’s would need double that.

[paulr]

There is a design code to determine how many CFMS blowers need to have to properly ventilate a bilge.
The cubic footage of a 396 is quite large. Although being large is not always a good thing as it very dificult getting around down there.
Thanks

[km1125]

I think on a gas installation they ALL should be blowing OUT of the bilge.

[Alanna Mo Cree]

All four on my gas installation blow out.

[bud37]

Source of the post There is a design code to determine how many CFMS blowers need to have to properly ventilate a bilge.
The cubic footage of a 396 is quite large. Although being large is not always a good thing as it very dificult getting around down there.
Thanks

Here is a read for those engineering types.....

https://safeafloat.com/wp-content/uploa ... l-4-14.pdf

[paulr]

Thanks for the article.
The article mentions the word blower several time in the beginning.
To me a blower can push air one way or the other.
The term "exhaust blower" is not mentioned until further down into the article. The term exhaust blower does mean something to me. It means it is pulling something out so this answers my question whether a blower blows in or out.
What started all this was the fact there are articles out there where the writer experienced poor engine performance due to insuficient air flow to his large displacement engines due to poor ventilation.
Anyway I will be sure my unofficial mechanic installed the the exhaust blowers in the proper orientation.
Thanks for the input.