Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: ScubaGuy on April 01, 2015, 09:41:45 pm

Title: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on April 01, 2015, 09:41:45 pm
Our water pump has been making more and more racket the last week or so.... to the point where we have been turning it off before it gets to full pressure (which is also when it reaches full noise).  :thumbsdown:

I took down the panels covering everything to take a look around and was a bit suprised by a couple of things.

Pump was made in Dec 1996, so it's original, it seems.  Shurflo 2088-403-144  2.8gpm 45psi
There's no strainer of any kind that I can find.  I half expected to find a clogged up strainer.
All plumbling is ridged PEX.  I thought there would be flexible lines from the tank to the pump and the pump to the water manifold. 

Lots of options on (non variable speed) Shurflo replacement pumps:
200-210-39 2.8GPM, 45 PSI (I think) Spare that came with the coach, FREE

2088-554-144 12 Volts, 3.5 Gallons Per Minute, 45 Psi  (Basically the same pump, same pressure, higher flow) $75.00
Shurflo Fresh Water Pump Model 2088-554-144 12 Volts, 3.5 Gallons Per... (http://www.amazon.com/Shurflo-Fresh-2088-554-144-Gallons-Minute/dp/B00C1M6B1C/ref=pd_sbs_auto_2?ie=UTF8&refRID=0YBZA7SRYT8P77VQGRQY)

4008-101-E65 3.0 Revolution Water Pump, 3 Gallons Per Minute, 55 Psi (More pressure, but less flow than option above?)  $62.50
Amazon.com: SHURflo 4008-101-E65 3.0 Revolution Water Pump: Automotive (http://www.amazon.com/SHURflo-4008-101-E65-Revolution-Water-Pump/dp/B002XM5G70/ref=sr_1_1?s=automotive&ie=UTF8&qid=1427934330&sr=1-1&keywords=4008)

4048-153-E75 4 GPM, 55 Psi  $154.50
Amazon.com: Shurflo 4048153E75 Electric Water Pump: Automotive (http://www.amazon.com/Shurflo-4048153E75-Electric-Water-Pump/dp/B007RYMT7O/ref=sr_1_1?s=automotive&ie=UTF8&qid=1427934482&sr=1-1&keywords=shurflo+4048)

I don't mind spending the extra $90 for better water pressure, but if the shower head is 1.75GPM will I actually get a better shower?  Would this make it less likely that turning on the sink scalds the person in the shower? 

Are there other brands I should be looking at?  I don't have to stick with Shurflo, but getting almost 19 years out of a water pump seems pretty impressive to me.  ^.^d  Also, I'm not really interested in a variable speed pump, unless someone has a really good reason to consider one.  I have plenty of room for an accumulator tank or even two.


Some other things I think I should do:
Install flexible lines from the tank to pump and pump toward manifold, which I understand should help with any noise.  Amazon.com: SHURFLO (94-591-01) Pump Silencing Kit: Automotive (http://www.amazon.com/SHURFLO-94-591-01-Pump-Silencing-Kit/dp/B000WN5F96/ref=pd_bxgy_auto_text_z)

I think I should install a strainer?  Any reason not to? Amazon.com: SHURFLO (255-313) 1/2" Twist-On Pipe Strainer: Automotive (http://www.amazon.com/SHURFLO-255-313-Twist-On-Pipe-Strainer/dp/B000V2W0GE/ref=pd_bxgy_auto_text_y)

I also need to replace the accumulator tank which has been shot for a while.  I was thinking of using the 3 gallon one at the bottom of this page.  RV Water Filter Store: Standard Filter Canisters for Whole RV (http://www.rvwaterfilterstore.com/Pumps.htm)
I have tons of room here, any reason to be looking for a 5 gallon or bigger tank?
Sorry this is so long.  All thoughts are appreciated.

Thanks,
Douglas
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: John S on April 01, 2015, 10:26:06 pm
I do not know that I would get a bigger accumlator tank and I have no reason to dislike my current setup.  I know some people have gotten the variable pump and eliminated the acc tank and then put it back inline.  The flexible hose would help eliminate noise and be easier to install the pump too.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Barry & Cindy on April 01, 2015, 10:57:15 pm
We and others find the Shurflo 4008 works ok.  4048 is also ok.  Both are not variable and do not require an accumulator.  These pumps have a clever internal bypass to reduce pump cycling on low water flows.  We have used both and not noticed any pressure difference with shower or any other faucet.

We think that the small space saving plastic Shurflo 182-200 accumulator is an optional way to further help reduce pump cycling and probably extend pump life.  We recently added this accumulator  to our 4008.

Flexible lines in & out of pump may reduce sound transmission, but these pumps are pretty quiet.  But it is a very good idea (maybe a requirement) to add an input Shurflo input screen to keep stuff out of the pump rubber valves.

Very worthwhile to add ball valves on input and output pump lines to facilitate replacing future water pumps and to help if there is an unexpected leak.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Ecurb on April 01, 2015, 11:20:29 pm
I read his and got to wondering....the Aqua hot is rated 1.5 gpm continuous, the shower head is 1.75 gpm. If you increase the pressure will you force more than the 1.75 gpm thru the shower head. Of course you're mixing hot with cold water for a desired temperature so not using all of the hot at once, but will you over run your Aqua hot and constantly have to readjust your shower temp?  If it's a water heater then it's a moot point I guess.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: steve on April 02, 2015, 08:15:29 am
I think Remco (formerly Aquajet) makes some non variable pumps as well.  May be worth a look as well.

Remco : The Towing Experts (http://www.remcoindustries.com/RV/index.php)
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Gary Bouland (RIP) on April 02, 2015, 08:43:07 am
Douglas, Too bad you are not near me in Georgia, I have a new accumulator tank that you could have and a new in the box 5.7 Shurflo that I will sell for a steep discount.
Gary  B
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on April 02, 2015, 12:27:20 pm
I think Remco (formerly Aquajet) makes some non variable pumps as well.  May be worth a look as well.

Remco : The Towing Experts (http://www.remcoindustries.com/RV/index.php)
Thanks Steve I had not found those.

I like the pressure and the GPM, but should I be concerned about amps
Remco
5264-1E1-80A 12 Demand        3.0GPM  60Psi Viton Santoprene 1/2 MNPT — 2-Pin  12.0Amps
5266-1E1-80A 12 Demand        4.0GPM  60Psi Viton Santoprene 1/2 MNPT — 2-Pin  12.6Amps
5267-1E1-80A 12 Demand        5.0GPM  60Psi Viton Santoprene 1/2 MNPT — 2-Pin  16.3Amps
Shurflo
4008-101-E65 3.0  12 VDC,        3.0 GPM, 55 PSI, 7.5 Amps
4048-153-E75                              4.0 GPM, 55 PSI, 10 Amps

I read his and got to wondering....the Aqua hot is rated 1.5 gpm continuous, the shower head is 1.75 gpm. If you increase the pressure will you force more than the 1.75 gpm thru the shower head. Of course you're mixing hot with cold water for a desired temperature so not using all of the hot at once, but will you over run your Aqua hot and constantly have to readjust your shower temp?  If it's a water heater then it's a moot point I guess.
You definately have a point.  I do believe it's possible to over load the AquaHot, and I should definately have a 1.0 to 1.5 GPM shower head to help prevent that, but I haven't found a gold one I like yet, so I'm sticking with the Moen 1.75 for now.
I'm not to terribly worried about a bigger pump causing me to overwork the AquaHot, otherwise you would think it would be a huge problem in the Newell community, and as far as I know it isn't.  Seems a common Newell water pump is the Headhunter MACH 5 Multistage Fresh Water Pressure Pump - 115 Volt AC. Max Pressure 67 PSI (4.5bar) Max Flow - 20 GPM (76 lpm)  This thing has a cruise speed of 8GPM at 50MPH, errr 50Psi. 
Unfortunately, it exceeds my water pump budget by about a coach buck.  Amazon.com : MACH 5 Multistage Fresh Water Pressure Pump - 115 Volt AC - by... (http://www.amazon.com/MACH-Multistage-Fresh-Water-Pressure/dp/B0029K8K10/ref=sr_1_1?ie=UTF8&qid=1427990793&sr=8-1&keywords=headhunter+mach+5+water+pump)


Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on April 02, 2015, 12:44:58 pm
Barry & Cindy

You seem to have a unique perspective, having used both the 4008 and the 4048.  Can you expand on your experience a little.  It sounds like you didn't find any difference in performance between the 4008 and the 4048.  Is that really the case?  If someone flushs the toilet or opens another faucet does the cold pressure drop and the shower goes totally hot? 

Also, seems you have had both pumps but are currently using the 4008, why did you settle on that one over the 4048?

Thanks!
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: MAZ on April 02, 2015, 05:37:08 pm
I just replaced my pump yesterday with the original type. I don't know if this type would be of any interest.

Amazon.com: Flojet R4525743A 4.5 GPM VSD Pump: Automotive (http://www.amazon.com/Flojet-R4525743A-4-5-GPM-Pump/dp/B000KKB3G0)

Mark
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Bill Willett on April 02, 2015, 08:22:50 pm
When you replace the accumulator tank, get one that is for hot water, they use a different bladder material, we changed all of these on commercial laundry equipment, they just last longer.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: steve on April 02, 2015, 08:59:37 pm
I like the pressure and the GPM, but should I be concerned about amps
Good catch and certainly something to check further.

I would suspect the wire gauge in the coach is fine, but in addition you would have to check what fuses are in place.  And if you have one of  the 2 or 3 way relay switches on the pump, some of the older ones may not be rated for those amps.  So lots of extra checks, but you do get 3X the flow rate at the high PSI for those extra amps.  Probably easiest to stay with what you have if its rated at the same amps  ^.^d
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Barry & Cindy on April 03, 2015, 12:19:31 am
Quote
  It sounds like you didn't find any difference in performance between the 4008 and the 4048 
Our Shurflo 5.7 started to act up like many other 5.7 pumps, so it was replaced with a 4048.  We don't use water in our motorhome like we did in our stick home.  (California would be happy with us).

The 4048 & 4008 handle low faucet flows by bypassing water within the pump.  And if more bypass in needed, the electrical pressure switch opens and the pump cycles.  Since we don't usually run our faucets wide open, we found the 4048 with its higher capacity cycled.  We decided to install the 4008 to see if it would cycle less, and found it did cycle less but it still cycled.  So we recently added the small plastic accumulator and found the 4008 cycled less often.

We find the 4008 handles all of our water needs ok.  If we still had the 4048 plumbed in with our new accumulator, the 4048 would handle our water needs just fine.

We fill our water tank once a week and use our water pump for 100% of our faucet needs and our shower has a kitchen sprayer hose that is off unless button is pressed, so we don't usually have high water flows.

Normally no one turns on faucets or flushes toilet when shower is used, but I assume that water temp or volume will change if shower is flowing water at the same time with either pump.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Dave Katsuki on April 03, 2015, 12:39:31 am
Like Barry and Cindy, we have the 4008 and a little accumulator, installed with flexible lines, and very quiet!

The shower temperature change is IMO a different problem.  I installed a pressure balancing valve in the shower a while back, and it takes care of pressure changes in the coach whether on water pump or city water pressure.  Has a little shuttle in the valve that responds instantly (OK very fast...) to changes in pressure between the hot and cold supplies, so no problem if someone uses water in the kitchen while someone else is showering.

Pressure balancer is somewhat expensive, but SO worth it!

Here's the one I put in:

Moen 3570 M-PACT Moentrol 1/2-Inch CC Valve with Stops - Bathtub And Shower... (http://www.amazon.com/gp/product/B000XH9KF6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)

Soldering required (remove rubber gaskets before soldering...)
You can also get a version with new bezel and control knobs for significantly more $$.
I used the old bezel and knob.  Needed to drill holes for the new mounting screws, which were positioned differently.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: fouroureye on April 03, 2015, 06:27:29 am
My tank went south..

This is my solution, smaller, lighter but simpler and no bladder. It will last as long as the pvc. What's that a 1000 years? ^.^d
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Ed on April 03, 2015, 10:06:02 am

The PO of my coach replaced the water pump with an Aquatec pump. Model 55-Aquajet-AES. As Steve pointed out, Remco took over Aquatec.

I've owned many boats over the years and have had most every fresh water pump at one time or another. This Aquatec pump is very impressive. It is a variable speed type; 3.5 gpm; 60 psi; 6.5 amps max.

It's quiet, excellent water pressure, can be run dry, and needs no accumulator. If it fails, I'll replace it with the same pump.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Keith and Joyce on April 03, 2015, 01:06:42 pm
Gary,

Tried to send you a PM but your in-box is full.  I am interested in the water pump.

Keith
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on April 03, 2015, 01:33:55 pm
Wouldn't you know since tearing the bay apart to see what's going on in there, the pump has gotten quieter and quieter.  It's now, completely back to it's normal "slight rattle" sound. 

Like Barry and Cindy, we have the 4008 and a little accumulator, installed with flexible lines, and very quiet!

The shower temperature change is IMO a different problem.  I installed a pressure balancing valve in the shower a while back, and it takes care of pressure changes in the coach whether on water pump or city water pressure.  Has a little shuttle in the valve that responds instantly (OK very fast...) to changes in pressure between the hot and cold supplies, so no problem if someone uses water in the kitchen while someone else is showering.

Pressure balancer is somewhat expensive, but SO worth it!

Here's the one I put in:

Moen 3570 M-PACT Moentrol 1/2-Inch CC Valve with Stops - Bathtub And Shower... (http://www.amazon.com/gp/product/B000XH9KF6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)
Dave,
Thanks...you got me thinking and I think you are right.  We have pretty good pressure where we are so, I'm going to try taking a shower on city water and have Siren flush the toliet or run water at the kitchen sink.  If the temp changes wildly, like I think it will, then that is a totally different issue.  While more pressure might help the problem, it's not going to go away until I fix the actual problem.  I actually hope you are right.  Thanks again!
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on April 03, 2015, 01:46:06 pm
I think my next step is to get a new accumulator and flex lines and plumb in my "new to me" spare pump.  That should give me a baseline and if I'm still not happy with the water pressure, then I can go looking at bigger pumps.  (Which I probably will)

As far as accumulators go, I don't now why more wouldn't be better.  Other than the issue of space, which I have plenty of in that bay, why not go BIG?  It's only $13 to double my capacity.

WaterWorker HT-2B In-Line Pressure Well Tank, 2-Gallon Capacity, Blue  $44.05
WaterWorker HT-4B In-Line Pressure Well Tank, 4-Gallon Capacity, Blue -... (http://www.amazon.com/gp/product/B000BQOTOQ/ref=gno_cart_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER)
or
WaterWorker HT-4B In-Line Pressure Well Tank, 4-Gallon Capacity, Blue  $57.38
WaterWorker HT-4B In-Line Pressure Well Tank, 4-Gallon Capacity, Blue -... (http://www.amazon.com/gp/product/B000BQOTOQ/ref=gno_cart_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER)

I just don't see a downside to going with the larger accumulator.  What do I not know?

Thanks again everyone, very helpful info.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Michelle on April 03, 2015, 02:59:52 pm
Douglas,

We have found good service and prices from RV Water Filter Store for pumps and other water accessories (we just got a couple of new soft loops for our AquaJet, some very high quality fresh water hoses, and got our Travelsoft water softener a few years ago as well.

Here's the link to their pumps and accumulators (the latter are priced competitively to the ones you listed) RV Water Filter Store: Standard Filter Canisters for Whole RV (http://www.rvwaterfilterstore.com/Pumps.htm)
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Don & Tys on April 03, 2015, 03:14:25 pm
Ooh... me likey! They have a 12/24VDC version that is only about 10 GPM, but it is $100 more ::) I do like the idea of silent power though :o Probably cost more than a new HWH control box!
Don
Snip...
Seems a common Newell water pump is the Headhunter MACH 5 Multistage Fresh Water Pressure Pump - 115 Volt AC. Max Pressure 67 PSI (4.5bar) Max Flow - 20 GPM (76 lpm)  This thing has a cruise speed of 8GPM at 50MPH, errr 50Psi. 
Unfortunately, it exceeds my water pump budget by about a coach buck.  Amazon.com : MACH 5 Multistage Fresh Water Pressure Pump - 115 Volt AC - by...
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Barry & Cindy on April 03, 2015, 06:42:25 pm
FYI, Shurflo Extreme 5.7 water pump was an electronically controlled variable speed pump.  Many have failed in various ways and if the pump was within warranty (I think 3-years) Shurflo replaces them with a 4048.  Dealers can exchange them.
Shurflo found that their electronic control just did work well and over time most failed.  So a new or used 5.7 pump within warranty has value as a trade in.
The 5.7 electronic board can be bypassed and usually the pump can be used as a fixed speed pump cycling on the pressure switch.  An accumulator should probably be used.  We have a bypassed 5.7 pump that we use to pump water into fresh water tank, if needed.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on April 03, 2015, 07:08:07 pm
The 5.7 electronic board can be bypassed and usually the pump can be used as a fixed speed pump cycling on the pressure switch.  An accumulator should probably be used.  We have a bypassed 5.7 pump that we use to pump water into fresh water tank, if needed.
Barry,
Just out of idle curiocity, did the 5.7 have the same "water bypass" as the 4048 that replaced it?  Or if you disable the electronic is it 5.7GPM all the time.  Would that lead to frequent cycling?  And finally, if it's max pressure is 65Psi do you happen to know what the "cut in" pressure is?

Thanks again for all your help with this,
Douglas
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Barry & Cindy on April 04, 2015, 01:20:45 am
The Shurflo 5.7 did not have any internal water flow bypass.  As I remember it, the 5.7 has an epoxy covered circuit board in its base.  This board has a current sensing circuit with programmable instructions to slow down pump speed with Pulse Width Modulation (PWM).  Extensive testing showed this approach could work, but once the pump went into production, after a few years too many problems arose, so the pump was phased out and replaced with the clever 4048.
The 5.7 has a strong large motor and a normal pressure activated micro switch that opens when pump reaches an adjustable pressure.  Bypassing the electronics turns the pump into a fixed speed water pump, which normally needs an accumulator to smooth out the cycles caused by demand being less than the pump capacity.  Cycling does not necessarily hurt the pump, but can make for unsteady water flows.
Yes all fixed speed pumps without internal bypass may have frequent cycling.  Cut-in pressure is adjustable by turning a screw on the pressure switch located on the head of the pump.  A PSI gauge will show cut in and cut out pressures.  I don't know the differential between in & out, so for a 65psi cut out (which may be set higher), I don't know the cut in psi, but assume it to be about 10-15 psi lower.
The 12-volt positive wire goes into the 5.7 circuit board, and another positive wire comes from the circuit board to the pressure switch, which feeds the pump motor windings.  To bypass, just disconnect the wire from the board and connect the 12-volt positive directly to the pressure switch.
I have not used a bypassed Shurflo 5.7 for normal RV water pumping, so I don't know for sure if there are any supply issues.  Our use is when we need to fill fresh water tank from external buckets, which works great.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Roger & Susan in Home2 on April 04, 2015, 11:03:41 am
Hi Douglas, I think the flex lines might help reduce noise but you probably want to mount the pump on some sort of isolation base as well.  You will always get some pressure variations with an accumulator tank, the range is determined by the on/off pressure settings in the pump. A bigger accumulator tank will make the cycles longer.  If you are getting temp variations in your shower when the pump cycles then check your shower valves or cartridge, one (side) is probably more clogged than the other. (More flow resistance on one side than the other)  This may be somewhere else. Thse are usually pretty cheap to replace.  New showers have temperature compensating mixing valves built in so that changes in pressure or flow rates on hot or cold sides shouldn't make much difference in temp.

The AH has a mixing valve so that the hot water coming out of it is limited to a max temp.

More random Saturday morning thoughts.  Roger

Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Don & Tys on April 04, 2015, 11:43:30 am
Hi John,
Nice idea which appeals to me because it would be easy to craft a tank which maximizes the available space for it. However, it seems like the bladder would be necessary to gain the most benefit. The air pre-charge on the bladder will stay as long as the bladder is intact but without a bladder, once the air in the PVC tanks is gone and there is no pressurized air space to pressurize the system, the benefit of having an accumulator tank is gone also until you drain the tank and start over... at least that is my understanding of how it works. I know that if the hot water tank loses its air gap, the expansion will cause the pressure relief valve to vent. I am thinking the principle is the same, but with the accumulator tank, it is the pump supplying the pressure instead of heat expansion caused by the boiler.
Don 

My tank went south..

This is my solution, smaller, lighter but simpler and no bladder. It will last as long as the pvc. What's that a 1000 years? ^.^d
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: krush on April 05, 2015, 08:06:14 pm
I installed a Remco variable speed pump. http://www.rvupgradestore.com/category-s/317.htm?Search=AQUAJETES&Submit= This place had the best price I could find.

I also used flexibible hoses to/from the pump to isolate it. It is much quieter. Installed winterizing bypasses too and orderd other stuff from that site as they seemed to have the best prices.

I left my accumulator in place, but I will probably pump it up to 80-90PSI. Just above pump cut off, but still be there to allow it to absorb expansion from the hot water heater if needed. I haven't used the new pump except to winterize--I will say it is very quiet.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: ScubaGuy on June 20, 2015, 12:43:31 pm
I've installed my new Shurflo 4048 water pump and I'm having two problems.

1.  With the pump and water fill solenoid off , if I hook up to city water, the city water flows back through the pump and fills the fresh water tank.  My 18 year old pump never did this, and I thought this pump was supposed to have a built-in check valve.  :help:

2.  The pump is causing some flickering in the led lights in my kitchen.  It maybe causing it in the ones that are still halogen, but it's especially bad in the cheap wafer leds over my kitchen sink.  Could this pump be drawing to much power for the relay that's powering it?  I seem to recall reading about that being a problem with some other pumps.

On the plus side, it's very very quiet, and has very good water pressure.  I just need to get the bugs out.
Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: jor on June 20, 2015, 04:41:49 pm
Quote
but should I be concerned about amps
One thing to keep in mind if you go with a 10a or more pump. You may (probably will) have to replace your water pump latching relay if you still have the original. If you do, might as well replace the relay for the water fill too. The photo shows both of the original relays in a 99 320.
jor

Title: Re: Time to replace water pump, accumulator, fill valve...maybe more
Post by: Roger & Susan in Home2 on June 20, 2015, 05:17:26 pm
Hey Still...

Amazons info on the Shurflo 4048153E75 Electric Water Pump says it has a back flow preventer.  If the plumbing is correct seems like it should not flow backwards.  Not good to be filling the tank when you don't want it to be filling.

I have noticed my LR LED pulse once for a fraction of a second when the water pump is turned on.  I only notice it at night when all,the lights are off and the pump gets turned on.  I have not solved it yet. In my coach the power for the ceiling lights on the slide side went through a relay above the MW somthat when the room was in those lights were off. The lights back in the kitchen area have a relay as well for the same function.  When I added a LR light dimmer the relay buzzed so I bypassed the relay.  Now all the LR lights are on even if the room is in but the dimmer works.  So the question is how does the three way water pump switch set up work? They are all momentary contact switches.  When the water pump is on the lights on all three switches are on. Probably a latching relay of some type.  Closing any switch closes the relay if it is open or opens the relay if it is closed.  Really not sure what happens next, why the indicator lights come on.  I think something is goofy in the ground paths as it pertains to the dimmer.  I should bypass the dimmer and see if it still happens.  Just haven't had enough time.

Here is what Steve had to say ...
"I've seen many odd things in the 12V systems, really there is no earth ground, just a return loop, so when things get noisy it can effect quite a few things.  Since the LED's are diodes they should only be on when current is flowing in the right direction.  So for them to pulse you have to be getting a positive voltage of at least several volts at them. 

Pumps / Motors will create quite a few spikes on the 12V line, they switch a lot of current and cause inductive kickback. When the motor's windings are carrying current, they generate a magnetic field. If the current is suddenly cut off, the magnetic field collapses and this will induce a current / voltage in the windings that is much higher than usual. It is very short lived but the values can be pretty high, this is often referred to as "back EMF" or "flyback".

The pump should be taking care of that, but sometimes a little extra help is needed.  If you want to experiment, and who does not, you can placing suppression / "free wheeling" diode across the pump voltage leads or at the relay.  Any regular rectifier diode should work.  Just put the diode in reverse (diode anode on negative side of pump and diode's cathode (stripped end) on positive lead). When switch opens, the diode will dissipate the "flyback".  Likewise a capacitor with a series resistor may work as well, sometimes called a snubber, it just trying to dampen the spikes and lengthen the time of the spike event."

Like a wild pictch at the ball game ... Right over my head.  Still digesting, still trying.  I wonder is this happens in the newer coaches with all LED lights and the fancy mulitplex control system.

My guess it that you need to have a clean ground path that is not in common with anything else other than the chassis.  Maybe some big diodes here and there too.  This is one that is tough to solve.  I have LED lights in a cabinet (not where the (Genie is) that come on when I open the door.  If the DirecTV Genie is on the HDMI signal gets interupted.  Close the door, good to go.  There is no 12v anything in the Genie.  Steve thought it might be an RF pulse from the LED lights coming on but it doesn't happen when the LED lights in the cabinet where the Genie is located come on when that door is opened.

Don't stay awake at night thinking about it.  Enjoy the LED lights.

Roger