Parallelling fuel pumps
 

Unless you have isolation valves to allow servicing of a parallel pump,
series works just as well for backup.
fuel wil flow through the unpowered pump.
Kelton
W4IND
s/v Isle Escape

Larry W4CSC wrote:
(Steven Shelikoff) wrote in
:


That begs the question why are you going to put two pumps in parallel if
you only want to run one at a time?

Steve



Backup?

Larry W4CSC

Parallelling fuel pumps
 

"Kelton Joyner" wrote in message
.. .
Unless you have isolation valves to allow servicing of a parallel pump,
series works just as well for backup.
fuel wil flow through the unpowered pump.

Depends on the type of pump. A possitive displacement pump (roller, vane,
etc.) will block the flow from the other pump.. This isn't a problem with a
diaphram or centrifigal it would work, however would subject the idle pump
components to pressure or could be a source of leakage once it failed.

Steve
s/v Good Intentions

Parallelling fuel pumps
 

"Kelton Joyner" wrote in message
.. .
Unless you have isolation valves to allow servicing of a parallel pump,
series works just as well for backup.
fuel wil flow through the unpowered pump.

Depends on the type of pump. A possitive displacement pump (roller, vane,
etc.) will block the flow from the other pump.. This isn't a problem with a
diaphram or centrifigal it would work, however would subject the idle pump
components to pressure or could be a source of leakage once it failed.

Steve
s/v Good Intentions

Parallelling fuel pumps
 

Steve,

I may have misunderstood you comment about limited lift. Why not install the
pump close to the tank so that the vertical suction run (lift) is as short
as possible? The pump will have lots of head to deliver to the engine.

surfnturf


"Steve" wrote in message
...

snip
I'm preparing to install a lift pump in series with my engine pump to
assist
in priming both the engine and the generator after I change filters.
Unfortunately the pump I purchased (AC) can only lift 1 ft., according to
the specs. Tha't ridiculous IMHO... My tanks are all down in the keels and
the lift for my service/day tank would be about 30 inches when the tank is
low. Sorry, didn't mean to bring my problems into your post.

Steve
s/v Good Intentions

Parallelling fuel pumps
 

Steve,

I may have misunderstood you comment about limited lift. Why not install the
pump close to the tank so that the vertical suction run (lift) is as short
as possible? The pump will have lots of head to deliver to the engine.

surfnturf


"Steve" wrote in message
...

snip
I'm preparing to install a lift pump in series with my engine pump to
assist
in priming both the engine and the generator after I change filters.
Unfortunately the pump I purchased (AC) can only lift 1 ft., according to
the specs. Tha't ridiculous IMHO... My tanks are all down in the keels and
the lift for my service/day tank would be about 30 inches when the tank is
low. Sorry, didn't mean to bring my problems into your post.

Steve
s/v Good Intentions

Parallelling fuel pumps
 

"surfnturf" wrote in message
news:Oqyec.90907$Ig.50300@pd7tw2no...

pump close to the tank so that the vertical suction run (lift) is as short
as possible? The pump will have lots of head to deliver to the engine.


From the top of the tank to the bottom is about 24", so even if I put the
pump on the tank top (not desireable since that is the bilge. Tanks are
integral.) the suction life, when the tank is low, would be more than the 1
ft spec. Might work fine as long as I don't loose suction. However the whole
idea is to have it as a priming pump.

Steve
s/v Good Intentions

Parallelling fuel pumps
 

"surfnturf" wrote in message
news:Oqyec.90907$Ig.50300@pd7tw2no...

pump close to the tank so that the vertical suction run (lift) is as short
as possible? The pump will have lots of head to deliver to the engine.


From the top of the tank to the bottom is about 24", so even if I put the
pump on the tank top (not desireable since that is the bilge. Tanks are
integral.) the suction life, when the tank is low, would be more than the 1
ft spec. Might work fine as long as I don't loose suction. However the whole
idea is to have it as a priming pump.

Steve
s/v Good Intentions

Parallelling fuel pumps
 

The Walbro is a 'wobble plate' diaphragm and therefore not suitable for
series installation. If the wobble plate stops in a position such
that one pump is blocked then both pumps will not flow.

For parallel installation application - a simple thumb-cock on the
outlet of each pump would be sufficient.


In article , Kelton Joyner
wrote:

Unless you have isolation valves to allow servicing of a parallel pump,
series works just as well for backup.
fuel wil flow through the unpowered pump.
Kelton
W4IND
s/v Isle Escape

Larry W4CSC wrote:
(Steven Shelikoff) wrote in
:


That begs the question why are you going to put two pumps in parallel if
you only want to run one at a time?

Steve



Backup?

Larry W4CSC

Parallelling fuel pumps
 

The Walbro is a 'wobble plate' diaphragm and therefore not suitable for
series installation. If the wobble plate stops in a position such
that one pump is blocked then both pumps will not flow.

For parallel installation application - a simple thumb-cock on the
outlet of each pump would be sufficient.


In article , Kelton Joyner
wrote:

Unless you have isolation valves to allow servicing of a parallel pump,
series works just as well for backup.
fuel wil flow through the unpowered pump.
Kelton
W4IND
s/v Isle Escape

Larry W4CSC wrote:
(Steven Shelikoff) wrote in
:


That begs the question why are you going to put two pumps in parallel if
you only want to run one at a time?

Steve



Backup?

Larry W4CSC

Parallelling fuel pumps
 

Backup, of course.

"Steven Shelikoff" wrote in message
...
On Sun, 11 Apr 2004 21:57:42 -0400, "Doug Dotson"
wrote:

Is it possible/advisable to place 2 WALBRO fuel pumps
in parallel without any valves? My goal is to be able
to switch between pumps by just applying power to one
or the other without having to adjust valves.

That begs the question why are you going to put two pumps in parallel if
you only want to run one at a time?

Steve