I currently have problems giving the kids a warm bath, because our
bathtub draws more water than our tankless indirect water heater can
produce. If I could just ask the tub to draw less water, that would
fix the problem. Are there tub/shower valves that will restrict the
water flow when the water is hot, adjustable between 0% and 100% of
the available water? Thanks,
My valves which are modern, Kohler, temperature balancing valves for tubs,
do not allow the volume of water to be restricted, They only allow the
temperature to be adjusted. I can therefore see how you could have a flow
which exceeds your tankless heater's capacity to maintain hot water.
Can you restrict the flow in a simper manner, such as installing a
threaded-in piece at the discharge of the filling spout? Some spouts have a
threaded discharge opening where an optional spray or other piece can be
installed. A restricted flow orifice would slow down the demand on your
water heater. Alternately, can you increase the water heater discharge
temperature so that you will need less hot water to mix to the blended
This became common in valve designs a few years ago and I could never figure out
why. I assume the design assumption was that you would never need the tub fill
less than full on and the shower flow would be adjust by a separate valve on the
shower head. What you end up with is a screw type valve that forces you through
full cold before it gradually opens hot.
Install a hand-held shower head with a 6' hose. The flow through that
will likely be restricted enough to let the heater keep up. If the
heater's still having trouble, install a shower volume control:
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