DIYbanter - View Single Post - hot water in shower can only reach "warm" at its best in winter

wrote:
Hi,
I recently moved into a ten-year old house. The hot water of the shower
worked fine in summer. However, when the outside temperature begins to
drop down around 30, the hot water in the shower does not seem to work.
The faucet water is hot, but the shower water can only reach warm level
at the best. The heating system is in the garage and it is a new system
with only 5 months on it. Two bedrooms have shower, it seems both
showers have the same problem. The shower has one bolt - turning to the
right is cold water and turning the same bolt to the left is the hot
water. Would anyone please give me any hint on what might be wrong with
the hot water in the shower? Thank you very much. - Lily

That's a new one on me. Normally if there's a shower temperature
complaint it's because the hot water temperature on the water heater
might not be set high enough, or there are uninsulated pipes losing
heat on the way to the shower. Usually once the water is running the
heat loss in the pipe system is not too bad. Check the temperature
setting on the hot water heater to be sure.

If you have sufficiently hot water at the bathroom faucet, but the
shower is lukewarm, you might have a problem with the shower body
itself, or...you're mistaken on how the shower valve works. If you
turn the valve one way for cold and the opposite way for hot, how could
anyone possibly mix the correct water temperature?

I think it's time you played around with that shower control and find
out what it does. Sometimes they've a little non-intuitive and you
have to turn all the way past where you think it should be to get it
where you want it to be.

If you're still stumped, get the manufacturer's name off of the control
cover plate and give them a call. They'll tell you whether it's you or
the valve.

R