Hot Tub Plumbing

Manual Three-Port Values

The design of three-port valves takes water flow from one direction and divides it into a choice of two other directions.

Picture a Y, for example, with the water coming up the stem, then a diverter allows a choice between one of two directions (or a combination thereof). Conversely, the water flow might be coming from the top of the Y, from two different sources, where the diverter decides which source will continue down the stem, or mix some from each together.

Construction

The unit is made watertight by gaskets (items 5 and 6), and the diverter is held in the valve body by a cover (item 4) which secures to the housing with metal screws (item 1).

Maintenance and Repair

As the simple parts suggest, there's not too much that can go wrong with manual three-port valves; however, a few procedures are common.

INSTALLATION RATING: ADVANCED

Most three-port valves are glued directly to PVC pipe, using regular PVC cement as in any other fitting. Care should be exercised not to use too much glue, as excess glue can spill onto the diverter and cement it to the housing. Excess glue can also dry hard and sharp, cutting into the gasket each time the diverter is turned, creating leaks from one side to the other.

LUBRICATION RATING: EASY

For smooth operation, the gasket must be lubricated with pure silicone lubricant. Vaseline-like in consistency, this lubricant cannot be substituted. Most other lubricants are petroleum-based which will dissolve the gasket material and cause leaks. Lubrication should be done every 6 months or when operation feels stiff. This preventive maintenance is particularly important with motorized valves since the motor will continue to fight against the sticky valve until either the diverter and shaft break apart or, more often, an expensive valve motor burns out.

Lubrication is the most important maintenance item with any three-port valve. When the valve becomes stiff to turn, it places stress on the shaft. On older models, the shaft is a separate piece that screws onto the diverter. Particularly on these models, but actually on any model, the stress from forcing a sticky valve will separate the stem from the diverter. You will be turning the handle and stem, but not affecting the diverter. To repair this, remove the handle and cover, then pull out the diverter and replace it with a one-piece unit. If the gasket looks worn, replace that and lubricate it generously before reassembly.

REPAIRS RATING: EASY

Few things go wrong with these valves, but the breakdowns that do occur are annoying and recurrent. Before disassembling any valve, check its location in relation to the hot tub water level. If it is below the water level, opening the valve will flood the area. You must first shut off both the suction and return lines. When installations are made below water level, they are usually equipped with shut-off valves to isolate the equipment for just such repair or maintenance work. If the valves are above the water level, you will need to reprime the system after making repairs.

Leaks are the most common failure of these valves. The valve will sometimes leak from under the cover. Either the cover gasket is too compressed and needs replacement, or the cover is loose. The cover is attached to the valve housings with metal screws. If tightened too much, the screw will strip out the hole and not be able to be tightened. The only remedy is to use a slightly larger or longer sheet metal screw to get a new grip on the plastic material of the housing. Be sure to use stainless steel screws, or else the screw will rust and break down, causing a new leak.

If this has already been done and there is not enough material left in the housing for the screw to grip, you must replace the housing. I have managed to fill the enlarged hole with super-type glue or PVC glue and, after it dries, replace the screw. These repairs usually leak and are only temporary measures. You can also fill the hole with fiberglass resin, which usually lasts longer.

Leaks also occur where the shaft comes through the cover. Remove the handle and cover, and replace the two small 0-rings. Apply some silicone lubricant to the shaft before reassembly. This will lubricate the operation of the valve, decreasing friction that can wear out the 0-rings. The lubricant also acts as a further sealant.

Leaks can occur where the pipes join to the housing ports. In this case, the only solution is to replace the housing. I have tried to reglue the leaking area by removing the diverter and gluing from both inside and outside of the joint. This has never worked! Try if you will, but I think you'll be wasting your time and patience.

Hot Tub Plumbing Page:    1  |  2  |  3  |  4  |  5  |  6  |  7  |  8  |  9  |  10