Trying to resolve multiple issues with "New" RV. Considering a couple changes

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CruzinCarlz

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Joined
Sep 20, 2020
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15
Location
Nevada
I know this is the remodel section, I figured this might be the best area since I am considering making some changes while also resolving these nagging issues. I'm a plumber so I guess a my first approach is to work on the plumbing.

1. When the water pump is turned on, it will cycle every 5-10s even without any water use. I have inspected for leaks and there are none. I suspect this is a problem with the pressure switch or the integrated check valve but have not had a chance to troubleshoot with Shurflo. Model 4008-101-A65. The technical sheet shows shutoff at 55psi and turn on at 40psi.

1.5 Water pump is very loud when running. I discovered that it mounted to the plastic cabinet enclosure through 3/8" wood, so I think this actually amplifies the sound by vibrating the entire cabinet. After solving the pump cycling issue, I'm going to have to find a way to quite it.

2. The fresh water tank is rated for 57gal. (Pic below) The low point drain and the pump draw line are both pulling from 1.5" above the bottom of the tank! The tank total height is 8.5" I don't understand how this makes any sense?? If I cannot fully drain the fresh water tank then I am left with stagnant water. If I do sanitize the tank, I'm going to be left with sanitizer in the tank. Aside from those two shortcomings, this prevents me from being able to use approximately 17.5% of the fresh water, 10gal! Now I'm not sure if the 57gal is a gross or net rating, but either way when you're boondocking that is a big deal! Maybe I'm missing something, but it seems that this is a big problem.

3. Suburban oven: Will light up, but after one main burner cycle (comes to temp, then reverts to pilot) the pilot will shutoff also. After investigation I found that initially the pilot burner will burn smooth, but for some reason after the main burner is on for a few minutes the pilot flame will start to flicker in and out. With this intermittent flame, the thermocouple no longer sends a signal to keep the pilot on after the main burner shuts of and I'm left with no oven. So I have a good thermocouple, but some type of thermal expansion is causing a failure in the pilot tube. I will be contacting support for a replacement pilot assembly and hopefully that will solve it. I just don't understand how this problem can slip through the cracks. An inconvenient discovery when trying to cook a pizza for hungry kids lol.

fresh water tank and pump.jpg
 

John From Detroit

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Apr 12, 2005
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24,339
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Davison Michigan
Pilot light on oven may need service.. if the flame is not proper it won't heat the thermocouple.. or the thermocouple (Flame sensor) may need repositioning

Water pump sounds like the pump is leaking back to the fresh tank. (the check valve(s) in the pump leaking.

On my RV I had a leak, took me a long time to find it. Long, Long time. . and damage happened as a result (it was the water heater)
 

Ex-Calif

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May 15, 2020
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1,036
My pump was cycling like that - turned out to be operator error. I thought the city water valve/fill to the tank stayed in "open" when off city water. Water was "dribbling" back out the fill check valve at the city tap connection. Closed the "tank fill" valve and all was good.

Tank usable capacity is what it is. They all seem to be like that. My procedures manual says a 10% bleach solution, followed by fresh water flush, followed by vinegar solution flush and another fresh flush if there is still a weird taste. The first time I did it, I did the whole banana as the RV was new to me and had sat a long time. I think by the time all that was done there wasn't any concentration of stuff that would kill me.

Everything in my RV is loud. Water pump, air conditioner, furnace. When it's all going at once I can't even hear the TV - LOL...
 

UTTransplant

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Jul 20, 2014
Posts
2,434
Location
Cedar Falls, IA
For sound insulation, get some foam and stuff it around the water pump. My son’s skinny arms and lithe body were very helpful for the task in our travel trailer! the insulation helped, but it didn’t make the sound go away.
 

Lou Schneider

Site Team
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Mar 14, 2005
Posts
10,638
A pair of flexible lines coiled into loops isolating the pump from the plumbing lines and mounting the pump on a rubber isolation block instead of directly to the wood will quiet it down.

One cause of nuisance cycling is the water inside the hot water tank contracting as the tank cools down. Since the RV water system is sealed, there's no place to get makeup water until the pump cycles to make up the difference.

A one gallon accumulator tank like what is used on hot water heating systems will solve this problem. Get one that is drinking water approved and put it on the water pump outlet. It will also eliminate the pump short-cycling when you just barely open a water tap.
 

Gary RV_Wizard

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Feb 2, 2005
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72,155
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At our Silver Springs FL home
Here are a couple of online articles/videos that may help with the water pump noise.

 

CruzinCarlz

Member
Joined
Sep 20, 2020
Posts
15
Location
Nevada
Thanks for the replies!

I just wanted to come back and update that I have resolved a couple of the issues:

I contacted Shurflo tech support and the pump cycling was caused by a bypass pressure setting being too high. This can be adjusted by one of the screws on the side.

The oven was fixed by replacing the pilot tube assembly. Apparently this is a common manufacturer defect.

Still working to sort out the usable fresh water issue...
 

John From Detroit

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Joined
Apr 12, 2005
Posts
24,339
Location
Davison Michigan
I had that fresh tank drain issue as well. I could give your my opinion of the design but I think you already have it and melt your monitor down I won't want to do (Kind of heated language reaqired)

I found a petcock valve.. It had a fitting for a hose and a half inch thread.
There was a 2nd outlet on my tank. .. I applied some clear tubing to the fitting and it was still able to slip into the half inch hole. Removed the 2nd outlet strainer (it is easy to remove onee you pull the plug andscrewed the petcock in

A 2nd plastic tube slipped snugly over the outlet of the petcock and extended below the RV and thus the Tank bottom when draining. Siphoned nearly all the water out. the rest evaporated over time I suspect.

A wet/dry vacuum with a length of tubing is faster.
 
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