Water pump

[the road tribe]

While at campgrounds where there are no sewer typically fill our fresh water tank and just limit our water usage. My question is about the water pump. Is it bad to run the water slow so the pump is turning off and on repeatedly or should I just crank it up so it's on fully until I am done?

 

[Tulecreeper]

While at campgrounds where there are no sewer typically fill our fresh water tank and just limit our water usage. My question is about the water pump. Is it bad to run the water slow so the pump is turning off and on repeatedly or should I just crank it up so it's on fully until I am done?

Drive it like you stole it. If you have to baby it to make it last longer, it's better to have it fail and replace it with a better model sooner rather than later. IMHO, of course.

 

[Isaac-1]

There is a 3rd option, add a pressure accumulator to the cold water plumbing to slow pump cycling. The accumulator tank can be located anywhere on the cold water plumbing and does not need to be located near the pump. I have one T-ed into the cold water connection under the bathroom sink, Mine is I think a 2 gallon accumulator, which has the bonus of giving me enough water to flush the toilet and wash my hands a time or two during the night with the pump turned off. The do make smaller 1 quart accumulators that do much the same thing.

p.s. this looks just like the one I have Expansion Storage Tank 2 Gallon 1/2" FNPT

 

[the road tribe]

There is a 3rd option, add a pressure accumulator to the cold water plumbing to slow pump cycling. The accumulator tank can be located anywhere on the cold water plumbing and does not need to be located near the pump. I have one T-ed into the cold water connection under the bathroom sink, Mine is I think a 2 gallon accumulator, which has the bonus of giving me enough water to flush the toilet and wash my hands a time or two during the night with the pump turned off. The do make smaller 1 quart accumulators that do much the same thing.

p.s. this looks just like the one I have Expansion Storage Tank 2 Gallon 1/2" FNPT

This is a great idea, I don't know if I have the space under the sink but I am sure I can find somewhere to mount it near a cold water line. Thank you!

 

[Matt_C]

Tribe,
There is no problem with letting the potable pump start and stop as its control is set to do.
The accumulator can be in the cold water line anywhere and it will do the same thing.
Matt_C

 

[Gary RV_Wizard]

While at campgrounds where there are no sewer typically fill our fresh water tank and just limit our water usage. My question is about the water pump. Is it bad to run the water slow so the pump is turning off and on repeatedly or should I just crank it up so it's on fully until I am done?

No worries - just run the water at whatever flow rate suits you. It's not gonna wear it out or break anything. If the on/off chatter annoys you, swap it out for a variable speed model, which self-adjusts for different flow rates.

In my opinion a small accumulator tank doesn't help much. There isn't enough water volume and pressure head to do much more than delay the start of the pump cycle a moment or two. But that is subjective and more than a few RV owners love their accumulator tanks. It's worth a try if you have space for it..

 

[CharlesinGA]

Also, make sure that the water heater tank has a head of air on it, as the water heater owners manual describes. Both Suburban and Atwood require this, and it will act like an accumulator also.

PRESSURE-TEMPERATURE RELIEF VALVE WARNING SCALDING INJURY • Valve is not serviceable, it must be replaced. • Tampering with valve will result in scalding injury. • Tampering with valve will void warranty. WARNING EXPLOSION • Do not place a valve, plug or reducing coupling on outlet part of pressure-temperature relief valve. A Pressure Temperature Relief Valve, dripping while the water heater is running, DOES NOT mean it is defective. During normal expansion of water, as it is heated in the closed water system of a recreation vehicle, the Pressure Temperature Relief Valve will sometimes drip. The Atwood water heater tank is designed with an internal air gap at the top of the tank to reduce the possibility of dripping. In time, the expanding water will absorb this air and it must be restored. WARNING SCALDING INJURY • Turn off water heater before opening pressure-temperature relief valve to establish air space. Storage water must be cool.

From the Atwood manual

TO REPLACE THE AIR GAP FOLLOW THESE STEPS:
1. Turn off main water supply (the pump or water hook up source).
2. Let water cool or let run until cool.
3. Open the hot water faucet closest to the water heater.
4. Pull handle of pressure temperature relief valve straight out and allow water to flow until it stops.
5. Allow pressure temperature relief valve to snap shut; close faucet; turn on water supply.
6. Turn on water heater and test.
• At least once a year manually operate pressure-temperature relief valve (FIG 3-G). When pressure-temperature relief valve discharges again, repeat above procedure. For a permanent solution, we recommend one of the following: • Install a pressure relief valve in cold water inlet line to water heater and attach a drain line from valve to outside of coach. Set to relieve at 100-125 PSI. • Install a diaphragm-type expansion tank in cold water inlet line. Tank should be sized to allow for expansion of approximately 15 oz. of water and pre-charged to a pressure equal to water supply pressure. These devices can be obtained from a plumbing contractor or Service Center.

From the Suburban manual

WATER WEEPING OR DRIPPING FROM PRESSURE RELIEF VALVE You may experience water weeping or dripping from your water heater’s Pressure and Temperature (P & T) Relief Valve when your water heater is operating. Water weeping or dripping from the P & T Valve does not always mean the P & T Valve is defective. As water is heated, it expands. The water system in a recreational vehicle is a closed system and does not allow for the expansion of heated water. When the pressure of the water system exceeds the relieving point of the P & T Valve, the valve will relieve the excess pressure. Suburban recommends that a check valve not be installed directly at the inlet to the water heater tank. This will increase weeping of the pressure relief valve. WARNING Do not remove or plug the relief valve. One way to reduce the frequency of this occurrence is to maintain an air pocket at the top of the water heater tank. This air pocket will form in the tank by design. However, it will be reduced over time by the everyday use of your water heate

To replenish this air pocket:
1. Turn off water heater.
2. Turn off cold water supply line.
3. Open a faucet in the RV.
4. Pull out on the handle of the Pressure Relief (P & T) Valve and allow water to flow from the valve until it stops.
5. Release handle on P & T Valve - it should snap closed.
6. Close faucet and turn on cold water supply; as the tank fills, the air pocket will develop. Repeat this procedure as often as needed to reduce the frequency of the weeping of the P & T Valve. If the weeping persists after following this procedure, you may elect to install an expansion or accumulator tank in the cold water line between the tank and check valve to relieve the pressure caused by thermal expansion. Contact your local dealer for assistance.

Charles