I turn on the hot water tap for my bathtub, giving it maybe half a
turn, leaving it until the water is hot. I then turn on the cold water
tap, and only have to turn it a fraction of an inch or so before the
water is warm. If I turned it as much as the hot water tap, the water
wouldn't even be warm, it would be cold. What is the problem and how
can I fix it? (It's been like this for ages, and the distance you have
to turn the cold water tap before the temperature is optimum is
getting less and less.)
I don't know offhand what the temperature of the hottest water is, but
you would not want to stand in it in the shower (it is not scalding
hot). Similarly, you would not want to stand in the cold water either.
These are taps which turn in a round fashion counter-clockwise, by the
It would seem to me that if you have two taps, one hot, one cold, and
you turn the hot tap a certain distance like 2" counterclockwise in a
circle and the cold tap a fraction of an inch so it is barely "on" to
produce warm water, that something is wrong. There is virtually no
variation in the temperature of the water, it's either hot or cold
other than in a very limited range.
No. It means that you're using the tap to set a desired temperature.
If it wasn't meant to be adjustable, you'd have just one tap handle
and it would despence the hot and cold together equally and too bad
if you don't like the resulting temperature.
Your hot water feed path may be more restricted than the cold one which
can produce the kind of results you are seeing.
Put an empty bucket under the bath spout and time how long it takes to
fill it with hot water with the cold tap closed and the hot tap fully open.
Empty the bucket and repeat with the hot tap closed and the cold tap
If it takes significantly longer to fill the bucket with hot water than
with cold water you've located the problem.
Fixing it is another (and likely rather expensive) matter.
Expensive it may well be. But if one of the valves in the path has
never been fully opened after the last time it was closed, it might be
OP, your faucet works the way mine does. Once I learned that I could
control the temp with the cold water valve, it was actually simpler
than it was somewhere else I lived. I use the hot to set the volume of
water I want, and the cold to adjust the temperature.
If it the adjusting range is so small you can't get the right
temperature, that's a problem, but you seem to be bothered by more
than that, like the fact that they're not open the same amount. If
they ever are like that, it's a fluke.
You don't really have a problem. Your cold water is coming in at about
45 F and your hot water at 140 F or more. If you must have equal turns
of the taps, then cut down the cold water piping size a whole lot,
like to 1/4" pipe and even add a restrictor of some sort, like an
inline pressure regulator. Replacing the controls with a single handle
type will eliminate your worries, but you may get sticker shock over
the $$ for the change.
the comfort of our single handle temperature control valve was worth
every penny it cost and the miserable install job it was........
its used on our tub shower, tubs dont matter much but wild temp swings
on shower is horrible
Let's look at some hypothetical data. Assume your hot water is at 130F,
your cold water is at 45F, and your desired temperature after mixing is
110F. Further assume that both knobs allow the same amount of water to
flow through when opened the same amount and each allows 2 gallons per
minute (GPM) flow when fully open.
Open the hot knob half way. You now have 1 GPM at 130F.
Open the cold knob half way. You now have 2 GPM at (130+45)/2 87.5F--way too cold.
Although the physics is probably not this simple, you can see that
you'll never get the temperature you want by opening both valves
Others have pointed out that physical conditions in your water system
can effect the temperature, maybe more than the mixing temperatures.
I would start by replacing the washers. It's easy and cheap, and it
probably needs to be done anyway. Maybe it'll help, maybe not, but
you'll be out less than a buck.
It is very possible that the hot water supply is clogged somewhere
between the heater and the tap. If there is some kind of strainer on
the hot water, cleaning it may help. If the pipes are partly closed
off, they may be cleaned or they can be replaced. A partly clogged hot
water will reduce the amount delivered.
Then again it may be simply a matter of the temperatures of the
cold vs hot water.
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