Plumbing in a manufactured home can be quite different than plumbing in a site-built home. In fact different enough that plumbers in many areas will not work on mobile homes. Why? Some plumbers don't like to work on the new plastic waterlines. Others don't like the fact that things such as tub faucets and drains aren't standard. Another reason is just plain laziness -- too much work to crawl under a home to get at a waterline. There is also, "You just never know what kind of plumbing mess I'll find, so why mess with it at all?"

Today's plumbing in manufactured homes can be described as on the cutting-edge of technology.' Because codes for site-built houses are strict and hard to change, mobile-home manufacturers are often the first to test new technology. Thanks to mobile home manufacturers, this country is now seeing a shift towards plastic waterlines -- more specifically, a shift to cross-linked polyethylene (pex).

Working with plastic waterlines is very simple, easy and fast. So why would plumbers scoff at that? One reason is that in many areas, codes for site-built homes have changed very little over the years. This has given many plumbers a good reason for not wanting to learn anything new. In fact, those same plumbers probably despise the new technology; therefore, they refuse to work on mobile homes.

If your having trouble finding someone to work on your plumbing and you don't want to attempt it yourself, try contacting a manufactured home repair company instead of a plumber.

Waterlines

In the past many mobile homes were built using galvanized pipe or copper for waterlines. If you have an older mobile home, most likely you have the metal galvanized pipes. Today, galvanized pipe has become the headache of the industry as it tends to corrode shut. Galvanized pipes are no longer used for waterlines, and homeowners who have galvanized will experience loss of water pressure or rust particles in their water due to the corrosion in the pipes. The only solution to that problem is to replace them.

Copper, on the other hand, is still occasionally used but has become quite expensive and much more time consuming to install. Although copper waterlines will not corrode, cold weather can be deadly on them. If it freezes, copper either bursts or expands so no fittings will fit, making repairs about impossible. Plus, both products are difficult for the average homeowner to work with. This gave life to another alternative -- plastic waterlines.

At first the most popular plastic waterline was polybutylene, a flexible gray or black-colored plastic waterline. In the late eighty's and mid nineteen-ninety's, many of the plastic fittings (right picture) that were used to connect polybutylene tubing were substandard; they would become brittle, crack and break. A class-action suit resulted and today polybutylene is no longer manufactured.

Anytime work is being done and plastic fittings are discovered, they should be removed. Brass or copper fittings are used today with the pex waterlines, polybutylene's suitable replacement.

Between pex and CPVC (hard rigid plastic) waterlines, pex provides the most resistance against corrosion and has an ability to “remember” its shape. That feature helps prevent the pipe from bursting under extreme conditions such as freezing. CPVC, copper and pex are waterlines available on the market today, and pex is by far the more superior. Both pex and CPVC products withstand heat very well. One advantage of CPVC is that it can be glued (solvent welded) which requires no tools for assembly. But like copper, it cannot withstand freezing without damage. At the current time CPVC is probably the most widely available, but pex is rapidly making its way onto retailers shelves. When choosing your new waterline, consider using pex and investing in the crimping tools necessary to do the job.

If you want to know how to work with CPVC, copper or any other type of waterline, numerous books are available. The rest of this chapter will be devoted to working with pex.

No matter what type of waterlines (galvanized, copper, black, polybutylene, cpvc, pex) your mobile home currently has, you can easily repair leaks or do other plumbing projects by using materials available at your home improvement center or hardware store. For instance, several companies have available universal compression-type fittings and couplings designed to easily connect together about any type of waterline using only basic tools.

Most all homes have two sizes of waterlines -- ½ inch and ¾ inch (inside diameter). ¾ inch waterlines are generally only used as the main waterline leading in and out of the water heater. ½ inch is generally used everywhere else in the home. One exception may be the risers leading to the toilets or sinks which sometimes are 3/8 or 1/4 inch.

Today pex waterlines are pretty much the standard in the manufactured home industry. In many areas pex is also the plumbers choice for new conventionally-built houses. Probably the only turn-off with pex is that it is installed with crimp rings which require a special crimping tool. Not that long ago a crimping tool sold for over $150. Thanks to the popularity of pex, crimpers now sell for well under $100 and the costs will continue to fall. Investing in a pair of crimpers is a wise decision for anyone considering tackling their own plumbing. You could save 1 or 2 calls to a plumber and the tool would be paid for (and your neighbors would appreciate borrowing them!) You could delay the purchase of a crimper by skipping the rings and using compression fittings, the only other way to connect pex waterlines. But compression fittings aren't as secure as crimped fittings and the damage you could get from a blown compression fitting would pay for a whole box of crimping tools. The above picture shows a pex crimper, pex cutter, go/no go gauge (page 14-4), crimp rings and a few of the available insert fittings.

PEX to Polybutylene

As mentioned in the beginning of this chapter, pex is polybutylene's replacement. Once only available in clear or white, pex can now be found in a variety of colors including red, blue, white and clear. Because so many manufactured homes still contain the gray polybutylene, repairs are still necessary. Since parts for polybutylene systems are no longer available, repairs have to be made using pex. The repairs are simple, you just have to remember that anytime you connect pex to polybutylene, you need a pex to polybutylene' adapter (pictured right) available anywhere pex fittings are sold. In the adapter kit, the gold ring is used on the gray polybutylene line and the black ring is used on the white pex line. Besides being a different diameter, the polybutylene side of the fitting contains a lot more rings than the pex side. Do not use a regular pex to pex' coupler as the inside diameter of polybutylene is larger.

In the photo to the right, the top coupler is a pex to pex' adapter. The bottom coupler is a pex to polybutylene' adapter. On the right side of the pex to polybutylene adapter is the polybutylene connection. Notice how its thicker and the ring spacing is tighter.

Installing New Waterlines

As mentioned earlier, if you've got the old metal galvanized pipes, you're probably experiencing loss of water pressure and occasional chunks of rust coming through your waterlines. The only way to repair it is to replace it. When installing new pex lines, never worry about removing the old waterlines. If they aren't in the way, let them lie. The toughest part of replacing waterlines is working underneath the home in cramped space. But before you start doing the back stroke, be sure you understand how your home's plumbing system functions. Basically, there's not much to understand. In fact it can all be summed up in one paragraph. The ¾” main waterline comes into the house by the water heater and makes a tee. One side of the tee goes into the hot water heater which then feeds all the ½” hot waterlines. The other side of the tee feeds all the ½” cold waterlines. Congratulations! Go pick up your diploma as you just passed Plumbing 101. Codes Manufactured homes are built to a HUD code. Homes built to a UBC or any other code have stricter plumbing requirements. In most areas pex waterlines are acceptable but all fittings have to be accessible. In other words, connections cannot be made inside walls or underneath floors as they typically are in a manufactured home. For pex to meet codes under those conditions, manifolds are used. Think of a manifold as a hot and cold control panel. The hot side of your main line would flow into the hot control panel. The cold side would flow into the cold control panel. A separate waterline would run from the control panel to each fixture in house. For instance, in your bathroom three ½” cold waterlines would run from the cold panel to your bathroom sink, tub and toilet. To accomplish that and meet code, each waterline would need to be one long piece with no hidden fittings connecting additional pieces of waterline. The beauty of this system is that you wouldn't need to install shut-off valves at each fixture, but rather simply turn off the valve for that line at the manifold. Depending upon your area, your waterlines may need to be inspected by a building inspector. Find out before starting any major work. If your area is like most, building inspectors don't require mobile homes to meet any code but HUD. Making a crimp connection Step 1 – Using a pipe cutter, make a square cut. Remove any burrs or jagged edges. Step 2 – Slide the correct-sized crimp ring over the end of the pex waterline. Step 3 – Insert the fitting into the pipe until it hits the shoulder. The ring should be positioned 1/8 to ¼” from the end of the pipe. If you encounter difficulty with keeping the ring in place until crimped, gently squeeze the ring using a pliers. Do not oversqueeze with the pliers or you may not be able to get the cimping tool over the ring. Step 4 – With a properly calibrated crimper, squarely center the jaws over the ring and squeeze the handle one time. If crimped more than once, the connection must be cut out and redone. Step 5 – Remove crimper and check the ring using a GO/NO-GO gauge. A GO/NO-GO gauge will tell you if you've made a proper crimp. For each size of pipe the gauge will have two slots. The GO slot will slip over the ring, the NO-GO slot will not. If both slots (or neither slot) slip over the ring, then the connection must be cut out and redone once the crimper has been recalibrated. To recalibrate a crimper, one screw loosens and the other adjusts. Since all brands of crimpers adjust a bit differently, refer to your manual for more details Tips: When installing new waterlines, here are some tips for making the job easier. A) Purchase pex waterline in 20' sticks or lay out rolls several days ahead of time. Straight sticks are a lot easier to feed through the belly than rolls of pex that won't lay straight. B) Help feed long lines of pex through the belly by occasionally cutting an 8” slit in the belly and using your hand to help feed it along. Patch the belly once the line has reached its destination and has been tested for leaks. C) Run both the hot and cold lines together. Tape them together at the ends. D) Before feeding the hot and cold lines into the belly, label the cold line by wrapping a piece of black electrical tape on it every 5 feet or so. E) Never use a crimp ring that isn't quite round. F) Check the calibration of a crimping tool before each project. Check by crimping a ring on a scrap piece of waterline and checking with the GO/NO-GO gauge. G) When installing a copper to pex adapter, solder the adapter to the copper before crimping on the pex. H) Properly support the pipe on long open runs with fasteners every couple feet. Automatic fasteners make the job a cinch as they work somewhat like a staple gun. I) Do not expose pex pipe to UV light (sun) for more than 24 months. J) When running new lines, leave some slack for any future adjustments. K) But any polybutylene waterline left in your home in most cases will function properly if the plastic fittings are removed and the pipe is kept straight. Polybutylene with sharp bends in time will crack and leak. . Mark Bower owns Aberdeen Mobile Home Repair and is the author of "The Manual for Manufactured/Mobile Home Repair and Upgrade" available on this website.