HyVac 1 Technical Support
Please read complete once, before starting.
Because of some of the end applications, we get a lot of calls about
this same problem. It seems to go like this, “I have a HyVac 1 and it
doesn’t make enough vacuum anymore.” Or “I have a HyVac 1 and it is locked
up.” The main culprit is water contamination. The main applications seem
to be asphalt-testing labs, soil testing and vacuum distillation. This is a
good choice in a pump for the application, but more care needs to take place
regarding replacement of the contaminated oil. This is especially so when
the pump is going to be put on the shelf for a while.
When the pump is used to de-gas / de-aerate the asphalt
mix or soil mix or distill product often times the water covering the mix is
turned into a gas phase and pumped by the vacuum pressure and ends up in the
oil sump. You are not doing anything wrong, it is just what happens (This
is physical chemistry). Using traps like desiccant traps are a waste of
time to implement in our opinion. Desiccants do not stop water under
vacuum. Better solutions include more frequent changing of the oil. Leave
the pump run 24/7, no problem with our pumps, they are for continuous duty.
It is more difficult for rust to form with the pump running, if the surface
that rust would form on is in constant motion then there is less opportunity
for scale buildup. The most costly solution and best, is by purchasing and
installing a “cold trap”. These traps freeze the water before it gets into
the pump. They turn it from a gas phase back into a crystal state (frost).
This process technically is called “sublimation”. The traps do cost some
money, sometimes even more than the pump but do protect the pump.
Ok the problem is already here and our pump is
Not enough vacuum but pump is running.
Unplug the pump from the electrical source.
Drain the oil.
Rotate manually the pump pulley and drain oil again. Do it again.
We do this because oil gets caught in the trap of the
pump. This is the design of the pump and we need to get “most” of the oil
out so humor us.
Chances are that one of the vanes in the pump, usually
the exhaust vane, is stuck in the up position. To review this, you need to
remove the 4 screws on the very top of the pump and remove the top cover.
Remove the cover gasket if it is not adhered on.
There will also be a sheet metal baffle plate that is a
little piece of sheet metal with 2 screws in it. Remove this animal also.
If you drop the screw in the pump, don’t have a heart attack, but upend the
pump later and make sure it falls out. Once the plate is out you should be
able to see the top working part of the pump.
Manually rotate the pulley while looking in the top of
the pump. You will see 2 springs attached to 2 lever arms. These lever
arms go up and down as the pulley rotates. If one is stuck, it doesn’t move
up and down with the action of the pump. Probably this is because of rust
formation in the slot the vane travels in. When we make these the vanes are
made to a thickness tolerance of -.0005” so a little rust can stop the
function of the vane going up and down. Don’t worry we have a relatively
Remove the springs from the lever arm and spring post.
Put aside. If the spring is not there or broken, you may need a new
spring/springs. Sometimes if the springs aren’t there it is may be in the
bottom of the pump oil case. Remove by upending the pump so the oil drains
out and check for spring/s.
Move the lever arms out of the way so you can see the 2
vanes. These are the thin piece of metal that generally go up and down in a
slot. Care should be taken as one of the vanes goes in a special way, the
one with the bevel cut on it. If the vane comes out of the pump please
immediately, before you let go of the pliers, mark which end of the vane is
into the pump and which way it faces on the pump. The perpendicular
specification is important and if put in backwards the vane may not make
Using a pair of blunt nose pliers it is possible to
pull the vane up not out of the slot but we really just want to manually
actuate it up and down so that it rides freely in the slot as it would if
just the spring pressure was applied. The pump can be manually actuated to
allow for the maximum penetration of the vane down into the slot. Do both
vanes, there are two. This is a gentle but firm effort, not a gorilla
thing. If the vanes will not actuate to full extension into the pump try
using some solvent or degreaser, whatever so you can get the vane actuating
down into the slot.
With the vanes running smooth re-hook up the springs to
the lever arm and spring post. Manually actuate the pump using the pulley
to see if vanes are now going up and down with spring tension only. If
doing good, replace the baffle plate. Fill the pump with oil. Replace the
top cover and gasket. Plug it in and check it out. This generally fixes the
On conclusion please review oil change interval for the
pump and increase frequency of changes. When the pump is put away change
the oil fully, like you did in this exercise.
If the pump is totally locked up the vane may be stuck
in the down position not allowing the rotor to move around. In this case
the pliers need to remove the vane so we can use a little scotch brite on it
to clean it up. Remember to fully document the vane removal which side is
what facing what.
If after vane removal the pump still is locked up
tighter than a tick chances are you have to send it to us for a rebuild /
cleaning. Call us for a Return Goods Authorization (RGA).