Will a small on demand water heater restrict water flow?

[Hobby_Man22]

Not sure if its the valve cartridge all gunked up or the small on the demand water heater. I had a shower valve not put out hot water once, but never restricted flow

 

[finn]

Not sure if its the valve cartridge all gunked up or the small on the demand water heater. I had a shower valve not put out hot water once, but never restricted flow

Depends if the shower valve incorporates a pressure balance feature or not. Lower end valves likely don’t.