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Topic: Fresh Water Systems

Presenter: Steve and Andra Savage (See website)

Note: Presenter teaches occasionally at Camping World tech school. Taught several technical courses at the Conference, and is very knowledgeable. Maintains website that publishes motorhome owner reviews of their own units.

Water system in RV is very similar to the water system in your home -- the main difference being the pulsating pump. It's not mandatory to have two separate tanks, one black one gray. No such thing as a "standard size" holding tank. There is a great variation among manufacturers in the size holding tanks used. Need to read the specs for each unit.

Don't travel with full holding tanks, because this puts more stress on the tank and its mountings. Tanks are made out of polyethylene, and are repaired by a process called hot air welding. A repaired tank has about 90% of the strength of the original.

Piping to holding tanks is not the same material as used in homes. RVs use ABS, black in color, rather than PVC, which is white. The difference is PVC is not as impact resistant in cold temperatures. The only "parts" are the termination valves, which can benefit from lubrication. Simple to lubricate -- there are additives you can buy at RV supply stores that will do the job.

Suggests not staying connected to city water. Would prefer to fill fresh water tank and "live off of it", using the onboard water pump. This helps keep water fresh.

Problem: shower runs hot and cold intermittently: This is often an easy repair problem involving the check valve.

Low point drains are supposed to drain all water from the system. However, usually you can't count on them to do so...especially for winterizing.

All systems designed to operate on 40-50 PSI. But CG pressures vary greatly. That's why it's important to use pressure regulators. With higher pressure you may find what appears to be leak. When you take it in to be fixed, the tech hooks it up to his system which is lower, and can detect no leak.

Everyone needs a filter. It's used anytime you're hooked up to city water; or anytime you fill the fresh water tank. Some areas have poor water quality. These are not "purification" systems. The pump will pump 3.5 gallons per minute; but the purification unit will slow it to one half GPM. The filter under your galley sink needs to be removed when winterized, and is best stored "in water".

RV water systems need to be "winterized" when stored in cold weather to protect against freezing. Draining the water heater and emptying the low point water drains is NOT enough to winterize. Two basic ways:

1. Use air pressure to blow all the water out. This is the faster and least expensive way for those who own an air compressor. Start by draining water heater and low point drains, so all the easy water goes out. Run the water pump to empty fresh water tank. Close drains and reinstall water heater drain. (treat hot water tank per next section) Pressurize the system to 40-50 PSI. Open faucets and supplies to appliances until no water runs out (one at a time). Don't forget showers, outside showers, and even icemaker. Pour one cup of RV antifreeze into each drain and each holding tank. Let small amount run out of termination valves.

2. Safest way -- use RV antifreeze. Start by draining water heater and low point drains, so all the easy water goes out. Antifreeze is added to fresh water tank. Always use RV antifreeze, as automotive anitfreeze is toxic. Several gallons are dumped into the fresh water tank....perhaps 3 or 4 gallons. [Note: there is an aftermarket device that attaches directly to the water pump and requires much less antifreeze.] Hot water heater should have bypass valves on back of water heater. This is why you don't have to use antifreeze in hot water tank...it takes the water heater "out of the circuit", so no water is flowing into it. Turn valves so water is bypassed from hot water tank. Once there is sufficient antifreeeze in the fresh water tank, turn on water pump and pump sequentially through each and every water fixture.

Sanitize the fresh water system: Use 3/4 cup bleach to each 50 gallons of capacity -- or 1/4 cup for each 15 gallons. Fill tank completely and open faucets until smell of chlorine is distinct. Let stand for four hours. Drain system and flush with fresh water. Don't leave bleach solution in system as 12 vold pump can be damaged by bleach.

Pumps are noisy due to design and installation. It's supposed to be installed on a solid, non-reverberating surface. The rubber feet should be secured with #6 screws and not overtightened. Water pump noise is often the result of having the screws either backing out, making the unit loose; or having the screws torqued too far, nullifying the dampening effect of the rubber feet. The number of elbows and fittings increases noise. A pump upgrade can be achieved with Shurflow 2088 being replaced by WhisperKing. Even higher end pumps are now available for around $200.

Accumulator tanks reduce the frequency of pump cycling. However it has both upsides and downsides, and on balance may not be terribly valuable.

All pumps work by maintaining 40-50 pounds; and when it drops to around 20 PSI it automatically comes on. Most have strainer in front of the pump. They can be cleaned if necessary.

Common problems:

1. Pump cycles when nothing is turned on. Can be air in line, or a leaking fixture. Sometimes it's the commode invisibly leaking.

2. Pump doesn't run: Battery discharged? Pump not turned on? Fuse blown?

3. Monitor problems: If black water problem, it's often caused by dumping before the tank is nearly full. If you dump less often, it will flush the system out more completely. Can buy a bag of ice, dump it down the commode before you leave the next morning. This helps clean it. Bottom line, it's always better not to leave even the gray dump valve open, and to empty tanks when they're full enough to generate a strong cleansing action when emptied.