Possible Fresh Water System Freeze Damage
Dear RV Doctor:
We are purchasing a 2007 Winnebago motorhome with 16,000 miles on the odometer. Unfortunately, it was exposed to freezing temperatures with fresh water still in the system, and the water heater froze and cracked. The dealer replaced it. When the new water heater was installed, the water line from the engine (it has a motor-aid feature) was not sufficiently tightened. The water line gave out and caused the engine to blow, which also was replaced by the dealer. If nothing else goes wrong and the system is ready, we are considering going through with the purchase. However, we are worried that the water system was stressed by the freezing temperatures. What tests to the water system do you suggest that will catch any potential plumbing problems that may show up in the future? I am thinking of using higher than normal air pressure behind a filled water system. What water pressure should the system be able to handle?
Michael Lieberman, F371744, Las Cruces, New Mexico
Freeze damage to the fresh water plumbing system is indeed a concern, and proper testing is paramount prior to finalizing your purchase. The formal testing procedures performed at the factory during manufacture included pressurizing the system with air or water to between 80 psi and 100 psi for 10 minutes. Typically, in the aftermarket, these same tests can be performed by any certified or master certified RV technician using a specialty test device composed of a gauge, a manual shutoff valve, and a special adapter that keeps the city water inlet check valve depressed during the test.
Since the city water inlet employs a check valve that opens under incoming pressure “” typically between 1 psi and 5 psi “” testing through the city water entry without using the special fitting could allow small leaks to go unnoticed. So it’s important that the check valve be held open continually during the test. Here’s why. Until enough pressure leaks from within the system to create a loss in pressure sufficient to open the check valve, no loss in pressure would be noticed on the gauge upstream of the check valve if it’s not held open.
Air pressure is my preferred method just in case there are leaks. If you use water during the test, you could have quite a mess to clean up. In your case, it really doesn’t matter, since the system probably still has water in it. The test fitting is attached directly to the city water inlet and subjected to 80 psi of clean compressed air. Since this is the fresh water system, shop air, which could contain tool oils and contaminated moisture, should be avoided. In the not-so-distant past, the fresh water system plumbing was tested at 100 psi, but the National Fire Protection Association (NFPA) standards now only call for a minimum of 80 psi. If you have an ice maker, it is probably best to remove it from the system prior to testing in case the inlet valve is not designed for that much pressure. Check your owner’s manual to be sure. If no drop in pressure is noted after 10 minutes, it would seem that the water system could be deemed sound. In your case, I’d recommend a redundant test be performed after a road test, just to be sure. I also would suggest extending the test to 15 minutes rather than 10 minutes. Make sure to have some type of rider written into the purchase agreement in the event that additional leaks develop later.
It is very important to note that when testing is complete, residual pressure must be released through a faucet or low point drain to avoid damage to the check valve device. Backflow preventers and check valves are designed for directional flow, and pressure induced in the reverse direction may cause O-rings to be dislodged from their seats, resulting in a damaged product. The service provider also should check to make sure that any appliances or components (washing machine, ice maker, water filtration system, toilet, etc.) that utilize the fresh water system and include a shutoff valve are not leaking or damaged. They may have residual water left in them and hold pressure during the test but leak once they are used.
It does take a technician with sufficient training to perform this test correctly. The test gauge can be inserted anywhere in the fresh water system, but it usually is easiest at the city water inlet. If an alternate location is used and it is necessary to tap into the system to insert the test device, those fittings also will need to be tested under pressure with a soapy solution once the test device is removed and the system is fully pressurized and made functional.
If any drop in pressure is detected during the test, a leak exists somewhere. Soapy solution is applied to each fitting until the leak(s) are totally eliminated. If the leak is a crack somewhere along the length of the tubing, further troubleshooting will be necessary to locate the crack and replace that section of tubing. Remember, a new test should be run after replacing any component until the test proves there are no leaks anywhere in the entire fresh water system.
Time For New Tires
Dear RV Doctor:
I purchased a 2001 Fleetwood Bounder with original tires that have been regrooved and show no sign of cracking. I would like to know if it is safe to travel with these tires, or would you recommend that we replace them? They have 56,000 miles on them. We also have a side-to-side rocking condition that seems to have gotten worse over the last year. Could this be due to worn shocks?
Steve Walker, Madisonville, Kentucky
Just about every safety expert I know would cringe at the thought of you driving on 11-year-old tires (they actually may be older). The general consensus is that five years after manufacture, tires need to be inspected for damage inside each tire. A telltale history of any tire can be determined by inspecting the insides of the sidewalls and casings. Tires between 5 and 7 years old should be inspected annually and probably replaced at or near the 7-year mark, regardless of the remaining tread.
It’s widely known that motorhome tires rarely wear out; most simply age out. All tires sold in the United States have a four-digit code molded into one sidewall. The code begins with DOT, and the four digits indicate the week and year that the tire was produced. Have an experienced tire expert inspect your tires after determining the exact date of manufacture. If they are, as you say, the original tires for that Bounder, they most assuredly need to be replaced now. Likewise, you should have the motorhome inspected to determine what is causing the rocking motion you experience. It could indeed be the shocks, but a detailed inspection will reveal the true culprit(s). All suspension components “” not just the shocks “” should be thoroughly examined.
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