Keep Up The Pressure

The job of most pumps found on boats is to move liquids around from one place to another as quickly and efficiently as they can. Correct installation of these pumps can dramatically influence just how long a pump lasts before disaster strikes and it stops dead. Clearly, most rotary and diaphragm pumps have to be of reasonable quality to do their job properly but generally speaking, like fuel tanks, once pumps are installed they are instantly forgotten until the day of reckoning arrives and it expires.

To ensure maximum life from water pumps, for example, the first rule is location, location, location. Pumps installed in dry, ventilated areas will fare far better than pumps that are stuck in some wet, airless hole. The dreaded rust will soon be into our defenceless little friends way down there! The second rule with pumps is to fit effective filters along the piping supply system to prevent impellor blockage and subsequent damage. Some filters are quite useless in some cases especially where aluminium tanks are concerned. The aluminium hydroxide that forms inside tanks can take the form of granules and powder and can easily slip through larger gauges of mesh and clog the pump body.

Lastly, the use of an accumulator tank is recommended to ensure reliable and effective system function. With an accumulator tank in the system, the intervals between cut out and cut out will be longer when only small amounts of water are drawn off. This amounts to much less wear and tear on the pump itself.

WATER SUPPLY
Little do boaties realise that if they have a dockside direct water attachment system on their boat, incorrectly set check valves can put excess loads onto the pumps (and pipes) on the boat putting sensitive flanges and valves out of the game. These pressures must never be taken for granted and should be checked on a regular basis.

Remember, too many pumps are prone to failure if air is allowed to suck into the pipes. The water pressure fails, air is sucked in and the motor responds to the reduced load then accelerates and helps to burn out the now dry impellor very quickly. It is critical to keep these pumps supplied with plenty of water at all times.

LOCATION
Youd think to look at a new $300.00 diaphragm pump that it would last a lifetime. Properly looked after, they could but what chance do they stand when they are stuffed into wet, mouldy bilges and never looked at? Most pump failures are due to corrosion inside the pump body. Water gains ingress to the electrics and the corrosion starts. After all, why shouldnt they get wet inside if they are in a soaking environment ? They arent a Rolex after all! So steps must be taken, WD40, fish oil and sensible installation could help here.

WIRING When installing pumps, wiring is extremely important. Once again a common fault is to wire up an expensive pump with ten cent wiring. This will inevitably lead to problems. Wrong rated cable, bad connections and lack of decent contact breakers will take their toll and fail without warning. Check all cables and if in doubt, run new cables into your valuable pumps.

SPARES TO GO All pumps, water, fuel or even air must have some kind of propulsive device to move the fluids along from source to destination. Generally, they are known as impellors and come in all kinds of materials, metal, neoprene, plastic and rubber. They all have one thing in common. They will, one day, fail. The causes can be expiry of expected life hours, structural failure, foreign object ingress or burnout. The methods of replacement are fairly well documented but the key rule is: Keep spares fuses, impellors, clips, brushes and even a spare motor as well as spare instructions!

WHAT IF MY PUMP FAILS?
Check the obvious first. Power connections, contact breaker or fuse blown? Impellor jammed? Burned out? Motor just stuck? Broken drive belt? After the first things are looked at youll have to take the pump out and disassemble it. They can be tricky so sketch out a diagram first. Be careful of damaging gaskets and have some cleaning materials to hand. Wire brush, bronze wool, not steel, WD40, small screwdrivers. Naturally enough do not pull the pump down if its under warranty because it will become void.

Often you will find the brushes worn or stuck. The impellor might be broken and a piece jamming the motor or valve. Check all flanges, valves, belts and brushes, spray thoroughly with WD40 and clean carefully, ensuring no damage occurs to the copper winding armature. Eighty percent of the time, the repair will be simple and a few more years of life obtained from the motor and pump. Most spares for all popular makes are available from the importers and manufacturers and fairly easy to obtain.

If the worst happens a full repair should be obtainable from your pump dealer or agent See Below for breakout boxes!!

REPLACING MOTORS TIP!
Often the hard part of replacing the motor inside a pump is getting the rotor back past the brushes, which are spring loaded. Often you can keep the brushes back with masking tape against the springs. Once in, cut the tape and remove completely allowing the springs to release.

TIP!
Before pulling any DC motor apart keep a diagram nearby for when you re-assemble. Keep all parts in a dry cardboard box!

TIP!
Dont use steel wool for cleaning an electric motor! The steel fragments will stick to the magnets and ruin the motor.

TIP!
Test your motor on the bench with a 12 volt battery before re-installing. You will save time and temper if the motor doesnt work!

Terry Buddell is a freelance journalist and a Marine surveyor, boat designer and shipwright, He lives on board his yacht "The Nicky J Miller' that he built himself in The Gold Coast Australia and has sailed his yacht up the East Coast to the beautiful Whitsunday Islands. He is currently resident in Gladstone Queensland where he is building another boat for his collection! Terry can be contacted on arcus1@bigpond.com or http://www.dolphinboatplans.com