Water is hot in sink but not in shower/tub. Titan tankless heater. Also pressure drops in kitchen when running bath.

All plumbing fixtures should be on same pipe. That means, if you have hot water in the sink, you should have hot water in the tub, too.

How far is the sink from the tub / shower ? When all off, do you hear hissing sound like water is running ? When you open Hot water at the tub /shower, what happens ? - do you get any water ? cold water ? no water ?

Back to you

Milo

Hi Edward.

Most tub/shower faucets have a temperature limiting device... it's a safety device that reduces chances of burn/scald. Find your temperature limiting device and turn it up, but do not exceed 115F (buy thermometer at hardware store)... Not necessary to go above that!

The pressure drop you mention could simply be related to a volume issue. In other words, your pipes may be too small to handle multiple fixtures working at the same time, especially a tub and/or washing machine.

Mark