Walter,
The following was taken from the first page of the manual for the LG 3-MD-MT-HC which you can find here: http://www.franklin-electric.com/ir...iant-mag-drive/highly-corrosive-handling.aspx
"Your Little Giant pump is delivered to you completely pre-assembled
and pretested from the factory. It is ready for immediate
use. The pump may be installed in any position. It may be
mounted vertically with the pump head down. Proper plumbing
connections should be made, see specification table to determine
what size intake and discharge your pump has. Use a thread
sealer on all pipe connections and hand tighten only. Note: On HC
models a roll of Teflon® pipe seal tape is supplied. Do not use a
wrench to tighten the HC model connections, excessive force may
damage the plastic part. Make sure the wing nuts are tight before
operating the pump. Motor nameplates list all electrical data. Make
sure the pump is connected to proper voltage before operating.
When wiring pumps with no plug, the green (or green/yellow) wire
is the ground. The other two wires are line (live). Do not allow
the SC models to run dry (without fluid). However, because the
HC models utilize a carbon bushing in the impeller they maybe
allowed to run dry for periods up to eight hours at a time. These
pumps are not submersible, operate the pumps only in the in-line
mode. Do not put the units in liquid. Pump should be installed in
a dry area and protected from splash. These pumps are not self
priming models, they must be installed so that the pump head
(volute) is flooded at the time the pump is to be started. That is,
the inlet of the pump must be below the level of the surface of the
liquid being pumped.
With all due respect, I also think that what you said about air getting trapped in the pump head is B.S. Liquid passing through the pump head and the pressure differentials created by the impeller would rid the pump head of any air almost immediately if the pump head was properly flooded (primed) initially. Perhaps your comments are applicable to the March pumps only and if so, that would only serve to further convince me that the LG is a better way to go.
Here's what the manual says about the carbon bushings:
"The HC models utilize a carbon bushing between the impeller and
spindle. The use of this carbon bushing will allow these pumps
(HC series) to run dry (without fluid) for up to eight hours at a
time. Do not allow the SC models to run dry. They do not have the
carbon bushing and heat build up caused by friction will damage
the parts when SC models are run dry."
The following was taken from the first page of the manual for the LG 3-MD-MT-HC which you can find here: http://www.franklin-electric.com/ir...iant-mag-drive/highly-corrosive-handling.aspx
"Your Little Giant pump is delivered to you completely pre-assembled
and pretested from the factory. It is ready for immediate
use. The pump may be installed in any position. It may be
mounted vertically with the pump head down. Proper plumbing
connections should be made, see specification table to determine
what size intake and discharge your pump has. Use a thread
sealer on all pipe connections and hand tighten only. Note: On HC
models a roll of Teflon® pipe seal tape is supplied. Do not use a
wrench to tighten the HC model connections, excessive force may
damage the plastic part. Make sure the wing nuts are tight before
operating the pump. Motor nameplates list all electrical data. Make
sure the pump is connected to proper voltage before operating.
When wiring pumps with no plug, the green (or green/yellow) wire
is the ground. The other two wires are line (live). Do not allow
the SC models to run dry (without fluid). However, because the
HC models utilize a carbon bushing in the impeller they maybe
allowed to run dry for periods up to eight hours at a time. These
pumps are not submersible, operate the pumps only in the in-line
mode. Do not put the units in liquid. Pump should be installed in
a dry area and protected from splash. These pumps are not self
priming models, they must be installed so that the pump head
(volute) is flooded at the time the pump is to be started. That is,
the inlet of the pump must be below the level of the surface of the
liquid being pumped.
With all due respect, I also think that what you said about air getting trapped in the pump head is B.S. Liquid passing through the pump head and the pressure differentials created by the impeller would rid the pump head of any air almost immediately if the pump head was properly flooded (primed) initially. Perhaps your comments are applicable to the March pumps only and if so, that would only serve to further convince me that the LG is a better way to go.
Here's what the manual says about the carbon bushings:
"The HC models utilize a carbon bushing between the impeller and
spindle. The use of this carbon bushing will allow these pumps
(HC series) to run dry (without fluid) for up to eight hours at a
time. Do not allow the SC models to run dry. They do not have the
carbon bushing and heat build up caused by friction will damage
the parts when SC models are run dry."