Low Water Pump Pressure

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brucegledhill

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Jul 22, 2017
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This relates to a 2015 Coachmen Catalina travel trailer.  The water pressure from my 12v water pump is very low.  The freshwater tank is full and the pump shuts off once system is pressurized.  The pressure is fine when I draw water in from the antifreeze fill line and quickly sucks a gallon jug dry.  All is fine when connected to city water.  Any thoughts?

Bruce G.
 
brucegledhill said:
This relates to a 2015 Coachmen Catalina travel trailer.  The water pressure from my 12v water pump is very low.  The freshwater tank is full and the pump shuts off once system is pressurized.  The pressure is fine when I draw water in from the antifreeze fill line and quickly sucks a gallon jug dry.  All is fine when connected to city water.  Any thoughts?

Bruce G.
Click to expand...

Maybe you're expecting too much from it. The shore power hose may be at 60 PSI and the pump may only be able to put out 40 PSI. Does it seem  to run OK?
I think thee is a place someplace on the pump to increase the pressure but I don't know where. Someone else may have that answer.
 
If you have a quick spurt of good pressure and then far less, there may be a restriction between the tank and the pump.
 
You said the pump drew well from the antifreeze jug ==> pump functions well.

The pump, drawing from the fresh water tank, never does get the job done.  ==> blockage between the tank and pump.

Sounds like a valve in the wrong position.

Is there a valve to select city water or tank?  City water filling tank or feed RV?  One of these may be in the wrong position.  Is the antifreeze jug valve closed?
There is usually a filter on the pump supply line somewhere.  It may be clogged.

Good luck in your search!
 
Did the pump ever work better?  Did you buy the unit new or used?

There should be a lever to choose between "fill tank" and "city water"  make sure after filling the fresh water tank that
the lever gets turned back to "city water" even if you are going to unhook from a water source.

One thing you could try is when hooked to a water source (and it's turned on) use the water pump too.  If there is any
air in the pump system it might push it out and then it might work better.  Worth a try???
 
First thank you for your replies and suggestions.  I purchased the TT new and occasionally used the water pump over the last 3 years, including recently, with great performance.  It still pumps full force from the antifreeze fill line t'd into the pump suction.  When I valve off the antifreeze line and open the freshwater tank line the system pressure builds up quickly but after an initial burst on opening the faucet, flow slows to a trickle.  There is no manual valve cutoff on the city water side but there is a checkvalve that prevents pressurized city water from backflowing into the pump.  Agree with one reply that there is likely an obstruction or restriction in the suction line from the freshwater tank to the pump, but not sure what to do.  Any further thoughts.

Thanks, Bruce G.
 
My guess is the check valve is stuck. You're not a newbie to this camper and had no problems with the pump before, and obviously know how to operate it. The pumps pulls suction good, and gets all kind of flow for the antifreeze mode, so to me that discounts a problem between the tank and the suction of the pump. I think it's a problem on the pump discharge side, and you are familiar with the valving arrangement. Check valves stick all the time. That's where I would look first since you have good supply from shore water, which comes in after that check valve. Good luck!
 
It seems the check valve is fine since you get full pressure from the winterizing line. If it doesn't seem to be the supply line from the fw tank to the pump, maybe the vent line next to the fill port is somehow blocked? If your fw tank fill connection has a cap on it, remove the cap and see if that might act as another vent and improve flow. (Assuming the tank fill line enters near the top of the tank since the exit from the tank to supply the pump will be at the bottom somewhere.)
 
Thanks for the very good feed back.

Does the system work on city water?

Try to isolate the problem area.  If city water works, the problem is NOT in any common flow paths.  Look at areas unique to the fresh water ==> pump  ==> RV water system area.  You have already eliminated major pieces of the system.

Check valves, filters and blocked vents are good places to check.
 
brucegledhill said:
First thank you for your replies and suggestions.  I purchased the TT new and occasionally used the water pump over the last 3 years, including recently, with great performance.  It still pumps full force from the antifreeze fill line t'd into the pump suction.  When I valve off the antifreeze line and open the freshwater tank line the system pressure builds up quickly but after an initial burst on opening the faucet, flow slows to a trickle.  There is no manual valve cutoff on the city water side but there is a checkvalve that prevents pressurized city water from backflowing into the pump.  Agree with one reply that there is likely an obstruction or restriction in the suction line from the freshwater tank to the pump, but not sure what to do.  Any further thoughts.

Thanks, Bruce G.
Click to expand...
Can you manually connect a water supply on the inlet side of the pump and "blow" that supply line in reverse to see if will, at least temporarily, solve the problem?
 
Thanks again, I'll try again with the latter suggestions.  I hadn't thought about the vent being blocked but I don't have a vent hole next to the fill line, not sure where it is.  I leave the fill cap open and see if that solves the problem, if so I know vent is blocked.  I'll also try backflushing from the antifreeze fill line into the tank to see if it clears an obstruction.

Bruce G.
 
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