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Topic: Water Pump Fuse Size (Read 2725 times) previous topic - next topic

Water Pump Fuse Size

When we added Seelevel we moved the water pump to the pump switch on the panel. It's protected by a 7.5 amp fuse behind the panel under the bathroom sink.

For the first time since the install I ran the water pump and it blew the 7.5 amp fuse and a replacement.

I'm guessing this water pump needs a bigger fuse?  Other than the display on the Seelevel the other switch is for the gas water heater.

Thoughts?
Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"

Re: Water Pump Fuse Size

Reply #1 –
I thought the water pump got its power from the water pump relay in the electrical service bay. Maybe that is the problem.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Water Pump Fuse Size

Reply #2 –
Always check the wiring diagram before making any changes, guessing will get you into trouble.
The selected media item is not currently available.Bill&Doris 97 U270 36'
University of Parris Island Class of 66
Semper Fi  Build# 5174 MC#17094

Re: Water Pump Fuse Size

Reply #3 –
Where exactly is this relay?  And how do I check it?
Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"

Re: Water Pump Fuse Size

Reply #4 –
It is behind the white removable panel in the bay ahead of the water tanks
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Water Pump Fuse Size

Reply #5 –
Call me I can describe where the relay is located. 813-215-3463
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Water Pump Fuse Size

Reply #6 –
The latching relay is probably behind the white panel on the side of the bigger bay, driver's side.  There are a couple different types of latching relays.  A flat gray/white one or a round VW relay.  It switches power to the water pump when any of the current water pump momentary switch closes a ground path to the relay.  That is how they get multiple switches to turn on and off the power to the pump.  I think the circuit breaker for the water pump is behind the same white panel.

From one year to the next and model,to model there are always a few small differences. 

It is generally a good practice to leave power to the pump off if you are not using the pump.  With the power on to the pump a broken water line or fitting that leaks will trigger the pump and it will empty the tank into your coach.

Here is a way to automatically switch the pump off ...
Water Pump Timer Automatically Switches Pump Off
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Water Pump Fuse Size

Reply #7 –
Don't think it's the relay. Looking at the Seelevel manual I noticed a code I'd seen in the panel prior to the fuse blowing:

"If a sender is unresponsive or there is an open circuit in the wiring so that the sender is not connected, the display will indicate an open circuit by showing "OPn" on the LED display."

Still not sure what to look for but continuing to read.
Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"

Re: Water Pump Fuse Size

Reply #8 –
If you are supplying power to the water pump via the switch on the SeeLevel panel then you need to use a relay.  The switch on the SeeLevel panel is only good for 7.5 amps.

The relay switches higher current power to the pump.  The switch engages the relay.  If it is an on/off switch then the relay probably draws power all the time the switch is on. 

This is not the same relay or the same type or relay as the latching relay.  The latching relay switches power on or off when triggered by a ground pulse.

From the SeeLevel Manual....
How to avoid damaging the display or pump switch due to excessive current:

Please be aware that the water pump switch circuit has a limitation on current draw of 7.5 amps, some large pumps can draw over 10 amps. These high drain pumps must use a relay or the display console printed circuit will overheat and damage the display permanently.
If the 12V supply line from the electrical panel does not have a 7.5 amp fuse rating, please be sure to install the supplied fuse holder with a 7.5 amp automotive style fuse inline on the +12V red wire.
WARNING: All power circuits must be fused. If a fuse is not provided with the system then it is the installer's responsibility to install a fuse with a maximum rating of 10 amps. A relay is required if more than 10 amps is needed for the pump.
 
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Water Pump Fuse Size

Reply #9 –
It's the in-line 7.5 amp fuse, at the display panel, that is blowing.
Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"

Re: Water Pump Fuse Size

Reply #10 –
Randy,

Check the amp draw for your pump's specs.  Most motorhomes are set up with a RELAY for the pump because there are multiple locations for turning the pump on/off.

If pump draw is within specs, but blowing the fuse, may need to use that circuit to close a relay with higher amp fuse and wiring "feeding the relay/pump".
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water Pump Fuse Size

Reply #11 –
 Thanks to all. With my limited knowledge and your help it appears the issue is a 12 amp draw Flowjet pump and a 7.5 am fuse.

Solution is either a lower rates pump or a relay.
Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"

Re: Water Pump Fuse Size

Reply #12 –
Blow the big bucks (listed here for $2.84) and use a 40 amp Bosch-style relay:
TE Connectivity - 1432785-1 - AgSnO Form C 12 V PI MINI-ISO Relay - Allied...

That will be better for the pump as well, as you can size the wiring so the pump doesn't see a big voltage drop.

BTW, unlike fuses, which are sized to protect the wire, going "bigger" on a relay just means more area in the points, so they last longer.  30-40 amp relays are available at any auto parts houses.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water Pump Fuse Size

Reply #13 –

Five including wiring harness and sockets for under $12.  Never hurts to have a few extras
Amazon.com: 5 Pack - EPAuto 30/40 AMP Relay Harness Spdt 12V Bosch Style:...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN
 

Re: Water Pump Fuse Size

Reply #14 –
Perfect Brett and Roger. Seelevel protects its display with a 7.5 amp fuse. If the draw in its switches is greater than 7.5 then a relay allows needed current to pass thru without harming display. Seelevel provides this info but we missed it on the install.

Will install relay this week.

Interesting that we missed this because it was only when we opened both spigots that the draw exceeded the 7.5 amps.
Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"