Re: Electric fuel pump vs original mechanical fuel pump
Posted by HH56 On 2021/11/23 16:12:55
To farther expand on Don's comment this is the typical way an electric rotary or vane type pump needs to be plumbed in order for the mechanical pump to be able to pull any fuel thru when the electric is off.
When electric is off the mechanical is pulling thru the check valve and when on, the check valve prevents flow from going backward to the tank or just circulating thru the pump again. This same plumbing could be used if internal passages in a solenoid or diaphragm type pump is found to be restricting too much of the flow.
In cases where the electric is putting out too much pressure an optional regulator could be installed after the electric pump but before the second tee. That location would regulate the pump output but not affect the mechanical pump being able to pull thru the check valve.
A larger check valve could be used although finding the combo fittings for the different sizes used might be harder than straight size fittings.
Attach file:
Rotary pump and check valve install.jpg (22.37 KB)
When electric is off the mechanical is pulling thru the check valve and when on, the check valve prevents flow from going backward to the tank or just circulating thru the pump again. This same plumbing could be used if internal passages in a solenoid or diaphragm type pump is found to be restricting too much of the flow.
In cases where the electric is putting out too much pressure an optional regulator could be installed after the electric pump but before the second tee. That location would regulate the pump output but not affect the mechanical pump being able to pull thru the check valve.
A larger check valve could be used although finding the combo fittings for the different sizes used might be harder than straight size fittings.
Attach file:
Rotary pump and check valve install.jpg (22.37 KB)
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