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The disaster for this month will be the failure of the water pump. This pump supplies coolant
to the still and refrigeration condensers of the drycleaning machine.
In order to cool the condensers, a
liquid called a “coolant” is forced
through the coils of the condensers
by a pump. In systems using a water
tower, the coolant is water; in
systems using a chiller it is either
water or a mixture of water and anti-
freeze called “brine.”
In water tower installations, the
pump is sometimes located on the
roof near the tower or on the floor near the drycleaning machine; in chillers the pump is
generally inside the enclosure housing the refrigeration components.
Before we get into managing this species of disaster, a few words about prevention.
Early warnings
These pumps seldom fail without giving ample warning of an evolving problem. If the circuit
breaker in the electrical panel that controls the pump trips frequently, it is a sure sign of
looming disaster.
If you are not afraid of electricity this would be the time to set the breaker for the pump in
the off position, remove the protective electrical plate at the rear of the pump, then take a good
look at the wire connections at both the pump.
There is precious little room for the wire connections in the end of the pump and pumps
vibrate, causing the screw connections or push-on connectors to loosen and eventually fail; in
many cases this is the problem area.
Using a flashlight observe if there is any melted insulation or bluing or discoloration of the
wires or connectors, if so replace them.
If you are not experienced in working with electricity hire an electrician for the following
procedures.
Remove the cover to the appropriate breaker panel and switch off the breaker controlling the
pump. Make sure screws holding the wires in place are securely tightened down.
Using a flashlight, observe if there is any melted insulation, bluing or discoloration of the wires
or circuit breaker connections or the area where the circuit breaker attaches to the power
busses in the breaker box.
Another harbinger of doom is frequent pump motor shutdown due to the motor’s internal
protective thermostat.
If this is the case, follow the same steps outlined in the previous paragraph and, in addition,
make sure the louvers that allow air to flow through the motor are free of lint, dust or
obstructions.
Temporary solution
You can drastically shorten the time this internal thermostat requires to reset by obtaining a
bag of ice, placing it inside another strong plastic bag and laying it on the far end of the pump
motor.
Remember, this is only a temporary solution.
The following goes for all equipment: Do not use the circuit breakers as switches to turn
equipment on and off!
This practice results in the degrading of the breakers’ performance and sometimes will keep
the breaker from tripping at the right current levels. Each machine should have a disconnect
close by; use this for switching instead of the breaker.
Excessive head pressure
The next pump killer is excessive head pressure.
This could be caused by a number of factors (see last month’s article) and will be indicated by
a high reading (45 PSI and above) on the pump outlet pressure gage, if you have one installed.
Also, the sound of the pump starting up will be different under high head pressure. Trying to
describe sounds is near impossible, but the best way I can do is to say that when starting the
pump the sound will take longer to even out (sorry best I could do).
Causes of this problem often lie in the bypass valve being shut or not sufficiently opened or
the clogging of strainers going into the drycleaning machinery.
When the pump goes down
OK, we’ve done our best to avoid the problem. What to do when the pump goes down in order
to keep running the drycleaning machine?
We give the drycleaning machine a “coolant bypass.”
You’re going to need two lengths of garden hose, preferably with an ID of 3/4 to 7/8".
One length must reach from a water source, like a hose bib outside the plant or to a faucet or
valve inside the plant to supply cold water.
The other length must reach outside through a door or to a toilet or sink to catch the used
water.
In addition, two adapters from the garden hose type fitting to pipe type fittings will also be
required.
On the drycleaning machine
Now let’s take a look at what’s available at the drycleaning machine end.
First, you’ll need to shut the valves going to the water pump on both the supply (high
pressure) and return (low pressure) side to prevent the city water that will be flowing from
bypassing the drycleaning machine.
On properly designed and installed cooling water systems, there should be connections for
pressure gages and thermostats as well as other possible locations where you can break into the
cooling water supply and return line to attach these hose connections.
If not, you will need to open unions to break into the piping and install tees to allow the hoses
to be hooked up.
If you are in the unenviable situation of having to install tees, also install hose bibs (these are
the valves that you connect garden hoses to) and you will have a permanent emergency
connection for future use.
Ready to go
OK, now were all “hooked up” (different meaning from when I grew up) and ready to go.
Turn on the water and make sure you’ve got flow through the drycleaning machine when it’s
in dry (many machines will prevent water flow when not required).
You may not be able to distill and dry at the same time. However, at least you can operate
while awaiting a new pump.
About new pumps
On the subject of new pumps — in many cases there is no need to replace the entire pump,
which requires lots of pipe disassembly and reassembly.
If you order exactly the same model pump it is usually possible to unbolt the motor/impellor
side from the raceway/piping side and just bolt on the new motor/impellor side onto the old
existing raceway/piping side.
The next logical question is, “In that case why purchase the entire pump?”
The answer is I have never been able to obtain a completely assembled motor/impellor
assembly, without the raceway, that’s why!
EZtimers has a new program available for obtaining illustrated instructions of these
procedures. Contact
bruce@eztimers.com for information.
The dreaded water pump failure
Bruce Grossman is chief
of R&D for EZtimers
Manufacturing, a
manufacturer of the
Sahara and Drop in the
Bucket line of high purity
separator water mister/
evaporators. For more
information on the
EZtimers product line
visit www.eztimers.com.
Questions can be
addressed to
bruce@eztimers.com or
call (702) 376-6693.
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