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The article for this month will be about how to handle the failure of the water pump. This
pump supplies coolant to the still and refrigeration condensers and in many cases the solvent
cooler of the drycleaning machine.
In order to cool these components, a liquid called “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. 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, 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.
Frequent shutdowns
Another harbinger of doom is frequent pump motor shut down due to the motor overheating,
which trips the motors 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.
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 electrical 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. Excessive head pressure 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 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.
Make a coolant bypass
OK, we’ve done our best to avoid the problem, but what to do when the pump fails so you can
continue 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 5/8 - 7/8".
One length needs to reach from a water source like a hose bib outside the plant or a faucet or
valve inside the plant in order to supply cold water; the other length needs to reach outside
through a door or to a toilet, sink or drain in order to remove the water which has flowed
through the machine.
In addition, two adapters from the garden hose type fitting to pipe type fittings will also be
required.
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 thermometers as well as other locations where you can break into the
cooling water supply on the water inlet and outlet sides in order to attach these hose
connections.
If not, you will need to open unions, 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 angled valves that you use for connecting garden hoses) and you will have a
permanent emergency connection for future use.
OK, now we’re all “hooked up” (different meaning today 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 the dry cycle (some machines will prevent water flow when not required).
You may not be able to distill and dry at the same time, but at least you can operate while
awaiting a new pump.
All new pump or just parts?
On the subject of new pumps — in many cases there is no need to replace the entire pump
requiring 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!
The illustration for this month shows a really simple and inexpensive method to prevent the
pump motor from overheating. Whether you’re currently experiencing overheating problems or
not, it’s well worth it to install this cooling device.
The dreaded water pump failure

Bruce Grossman is the
chief of R&D for EZtimers
Manufacturing, a
company that offers
several products for
testing and protecting a
plant’s boiler and steam
system — the Sentinel,
EZ-Level and Tattler
steam trap tester. Also,
the company has a line
of separator water
processing and disposal
equipment for
drycleanings machine
using any type of solvent
— the Sahara and Drop
in the Bucket misters.
Questions can be
addressed to
bruce@eztimers.com or
call (702) 376-6693.
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