Our rented house has an individual plastic water tank to which the colony supplies water from their tanks regularly. The main water pipe fixed to the tank that comes from the colony had a ball valve (PP-R type) which was failed recently.
As these pipes are of PPR, it is hard to get an expert plumber to fix things. Because of that reason my plumber replaced the ball valve with a Globe Valve that lets us replace "washer set" instead of the entire valve if failed in future.
Thought it was a good suggestion, but now I heard that using gate and globe valves to the main water supply is not a good idea. Also, while turning it off, the pipe above it shakes (not a big problem as it is PP-R).
Could anybody tell me if these issues worth worrying? Is it really not a good idea to use a Globe valve there?
Best Answer
A gate valve does not have a "washer set". The valve in the photo appears to be a globe valve.
I agree with your plumber that a globe valve is proper in that place. A gate valve or ball valve is intended to be seldom closed, usually to empty out pipes for winter exposure or to repair the plumbing. If you must operate a valve often, as part of your household routine, then a ball valve may not stand the wear.
Some differences among the most commonly used valve types:
A gate valve stops the flow by sliding a flat plate across the flow path. The advantage of a gate valve is that when fully opened it offers almost no restriction to the liquid flow. The main disadvantage of a gate valve is that the end of the gate must slide into a pocket to complete the seal, and this pocket is not flushed by the normal flow of liquid, so that scale and debris collects there and blocks the valve from fully closing.
A ball valve controls the flow by rotating a ball with a large hole in it. The advantage of a ball valve is that when fully opened it offers less restriction to the liquid flow than most other types (except perhaps a gate valve). The main disadvantage of a ball valve is that when the ball eventually wears down, there is no adjustment to tighten the mechanism and stop the leaking. The ball type should not be used where the valve must be operated frequently.
A globe valve operates by screwing a small disk, faced with a rubber washer, directly down onto an opening in a smooth plate, called the seat. The advantage of a globe valve is that it is simple to manufacture and maintain. As the washer and seat wear down, simply turning the handle little further completely stops the flow. Most users do not even notice this. When the washer becomes too worn to seal properly, it can easily (and almost intuitively) be replaced by an amateur. Even a damaged seat can be reground without special training -- just the proper tool. The disadvantage of the globe valve is that even when fully opened it still significantly restricts the liquid flow.
In your case the flow restriction will not be a problem because you are not using the flow directly in your shower etc. Even if you notice a difference, it will just take a bit longer to fill your tank.