Water Pump Replacement

[mcpandt]

Has anyone replaced their Shurflo 3 gallon per minute water pump with the Shurflo 4 gallon per minute pump?

The two pumps are identical in PSI, and in looking at the pictures it appears that they would install exactly the same. It would seem like the extra gallon per minute might make showering a little easier for my wife, and give us a little better flow when using more than one sink at a time.

Any drawbacks other than the cost?

[d23haynes57]

Does your rig have nay complicated controls where the increase in pump current may be a problem? Do you have enough hot water capacity to take that extra flow?

[mcpandt]

Originally Posted by d23haynes57

Does your rig have nay complicated controls where the increase in pump current may be a problem? Do you have enough hot water capacity to take that extra flow?

Good thoughts. I don't think there is anything particularly complicated. I really hadn't thought about the hot water heater. My wife typically showers first and I don't need as much hot water as she does. With the shut off on the shower head we typically don't run into issues.

I am already assuming that I might be dumping grey water a little more often.

[shepardmike]

Definitely need to look at power consumption between the two models.

[ekim]

I upgraded to 4048 pump. I recall the mounting points are different and it's 10 amps vs 7. In my case the 10A seems fine. My pump circuit is on a 20A breaker circuit with thin(ish) wire - 16 gauge I think, maybe 14.

[shoreco]

If you boondock, you'll use your water capacity 25% faster

[garykk]

As long as the amp draw does not exceed the wire or fuse you should be fine.

[alank]

A pump with 3 gpm capacity won't pump any more or less water through a 2 gmp shower head than a 4 gmp pump will. You said the pump pressures were the same. The 4 gpm pump will just cycle ON/OFF more often. The byass valve and pressure shut OFF switch regulate the pressure. Using a pressure gage, I've found factory settings to be between 45 and 50 psi.

Now if you turn the kitchen sink on full blast while the DW is in the shower, you may get less screams with the 4 gpm pump.

[zombiewoof]

I just went through this exercise about two months ago. I seriously looked at the 4 GPM pump you mention versus the 3 GPM pump that is standard and came with the coach. The OEM solid state relay will handle the current load of the 4 GPM pump. I looked at the pump curve for this pump and it maxed out at 10 amps though under normal operating conditions it is less than this. Your electronic circuit should handle it without modification since it is rated for 10 amps. Note that the 4 GPM pump is rated for 55 PSI, the same as the 3 GPM pump. If you have a single faucet open in the motorhome (kitchen, sink, shower) the water usage will be restricted by the flow rate of the the faucet and will not change with a 3 vs 4 GPM pump both rated at 55 PSI, within reason. It is only when you have multiple faucets open at the same time that the water usage per unit time will be greater with the 4 vs 3 GPM. I thought a lot about this since I boondock a fair amount of time. For me the I decided to stay with the 3 GPM unit. I was willing to compromise on flow rates with multiple spigots open to reduce water usage since it would make a difference when boondocking. That 4 GPM pump is a very nice (and pricey) unit though. Just my take on this. If I spent most of my time at RV parks I would be more inclined to use the 4 GPM. I say this because at a lot of full hookup sites the water pressure is so low I fill the fresh water tank and run off it using the pump. In this case the 4 GPM pump would be of benefit.

[ernieh]

The Spyder system may not handle the increased amps. I had to install a 30a relay for the increased load. Not a bad thing since the TMH supplied wiring is undersized to start with.