Adding frest water pump switches

[Jim Shaw]

My 2003 Monterey came with only one fresh water pump, and it is in the kitchen.  I would like to install one in the bathroom, and maybe one in the water bay where the outside shower is located.  Where can I obtain a wiring diagram, and what switches should I use.  I am aware runing the new wires may be a little difficult, but I believe I can do it OK.
Jim

[Tom Rogers]

For the switches, I would give Bend a call .... or even Monaco now that they are up and running.  A schematic would be nice to have, but as long as you locate your "incoming" HOT wire (at the switch or at the pump), you can wire on from there. You need to understand how 3, 4 and 5 way switching works though.  I only understand 3 way switching which is 2 receptacles, so can't help you there.

[Gerald Farris]

Your water pump is probably controled by a latching relay. If it is you will have to wire to the relay and not the pump.

If you do not have a latching relay, and you want to install multiple switches, you should install one so that you can turn the pump off or on from any switch.

Gerald

[Joel Ashley]

We assume you meant you wanted more switches for the one pump, not more pumps as stated.  I would think you can wire as many switches as you like as long as each switch runs a red ("hot" or "+") wire to the positive post of the pump, and taps into an always-on source from the batterys' positive side.  Just be sure the added load of the pump won't overtax the tapped circuit's fuse or breaker.   A better method, though, involves a relay.

As Gerald mentioned, if there is already a relay for the pump you'll wire to it, not the pump, hooking to the same post as the existing switch's wire does;  in which case smaller guage wire such as #14 could be used.  If there is no relay, I would opt to install one, as Gerald said, or else use at least the same guage wire as is already on the pump from the existing kitchen switch - for significantly long runs, I'd use even heavier wire to avoid voltage drop.  A relay is certainly your best choice however, and I definitely would install one if it were me.  

I would think adequate switches, similar to the existing one and probably the rocker type, could be found at Camping World or any auto parts store.  You'll have the option of paying a bit more for lamped switches that light up when they are on;  that could be helpful in your water bay location, for example, so it catches your eye and is less likely to be inadvertantly left on - an inconvenience when you try to turn off the pump at another switch inside and have to hike outside to the bay to get it off.  Just get switches that are rated to the potential current (amp) draw you anticipate - low amps for smaller wire if the relay is involved, and much higher amps for heavy duty wire if you "direct drive" the pump from each location.  I plead ignorance about any "3-way" switches as Tom mentioned, other than modern multiplex systems - this is a different ball game than AC house wiring where 3 and 4-way switched lighting circuits are common.

I'd in-line fuse any "direct drive" leads;  probably not necessary if you wire to a relay instead and so use minimal amps.  If you need to install a relay, get one that is sized to handle the pump's current draw in amps, which I'd think is printed on the pump's label.  Ask at Camping World parts or other RV supply or dealer's parts counter about the appropriate relay if you need one.

[Gerald Farris]

The down side to direct wiring mulitple switches to one pump without using a latching relay is that you can only turn the pump off from the switch that you turned it on with.

Gerald

[Bruce Benson]

Matching the question to the system on my coach has proved an interesting puzzle.  Like many with my generation of coaches, I have no wiring diagram to refer to and can only surmise how it is wired and built, then follow wires to see how good a guesser I was.  

My 4 water pump switches are rocker type but are temporary contact, meaning that they rock to the on or off position but always return to a neutral position when released.  I can turn on the pump at any of the 4 switches and turn it off at any of the 4 switches as well.  

If this system is done with relays (which I fully understand) rather than transistors (which are P.F.M. and never seem to work like I think they should) it would require two relays to make it work.  

The "on" relay would latch once it was energized by rocking any of the switches to the on position.  The latching would occur through the making of one of two sets of contacts in the relay which forms a sort of endless loop, powering the relay through itself.  The other set would turn on the pump and the indicator lights at all 4 of the switches.  

The second or "off" relay would have a set of made contacts that would become open when the relay was energized.  These contacts would be wired in the latching loop that is holding the "on" relay down.  The off relay would be energized by pushing any of the 4 switches to the off position.  This would then open the contacts in the latching loop and release the "on" relay (by breaking the "endless loop") turning off the pump.  When the switch is released the "off" relay would return to static which leaves everything off and ready for the next time the pump is turned on.

Interestingly, off on the switches is really not off.  It is off when it is centered.  When the top is pushed one current (to the "on" relay) is activated, when the bottom is pushed a different current (to the "off" relay) is activated.    

For my system that would mean 4 wires to each of the pump switches, one for power, one to the "on" relay, one to the "off" relay and one to ground the indicator light.  It would require 2 relays (Radio Shack), one with two sets of normally open contacts and one with one set of normally closed contacts.  The indicator light could be connected to the wire going to the "on" relay as this wire would remain hot when the relay is latched.  

Bruce

[MarcRodstein]

I also have an '03 Monterey and I am thinking about the same mod. The preferred way to do it is to install an Intellitech Monoplex Water Pump Switch. This is what is used on most of the higher end coaches. It is not expensive. See http://www.intellitec.com/PDF/5300145.000.pdf

If you do it, please let me know how you wind up running the wires. That's what has put me off from doing it so far.

[Joel Ashley]

Good explanation, Bruce.  I wasn't up on latching relays.  But sounds like a lot of wire involved.

Thanks.
Joel

[Tim Westman]

If you need a latching controller I have a couple of spares from my '05 Monterey.  Both are in working condition and new.  I would be more than happy to pass them on if you can use them.  I can be reached at 231-730-0346.

[Gerald Farris]

A latching relay system can be wired very easily with 2 wires to each switch by using a pulse type latching relay like the Magnecraft 711 series relay. In a pulse type relay the contacts transfer and reset when a unidirectional pulse is applied to the single coil using two (2) control wires. Therefore with this type relay all that is needed is a 12V wire through a momentary switch to supply a 12V pulse to the relay to change it's state from on to off or off to on.

Gerald

[MarcRodstein]

That's exactly how the Intellitec Monolpex relay works. I just bought one online at mccampingsupplies.com for $37.

[Joel Ashley]

Thanks for the input, Gerald.  By visiting Magnecraft's website I learned something about electric systems I had no prior exposure to, other than some of the modern onboard systems I've used on our rig without a clue how they mechanically worked.

[Bruce Benson]

See, it is the magic in the transistors that makes the Magnecraft thing work.  I am sure that it uses a couple of transistors to replace the two relays that my ancient mind sees as needed.

This switch, however, differs from the factory installed system on my coach in that you turn the pump off and on by cycling the same button.  Mine has a clear off and on switch at each location.  Without an indicator light you would only know if you were turning it on or off by the sound of the pump or the flow of the water.      

For the wiring, it would be possible to to use a wireless remote switch to operate the Magnecraft unit or maybe even eliminate it all together with the proper wireless switch.  Finding one that works without AC is a hurdle.  Here is an example from West Marine:
     http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&productId=59308

I am sure there are other, cheaper sources.  Someone smarter than I could probably modify a battery powered wireless door bell to operate the Magnecraft.  You can pick these up for less than $7 each.   You would have to have a transmitter at each location that you want the switch.

Bruce