Hot water surges

[leftheart]

I have a tankless water heater and I have 2 showers one is fine, the other starts off normal (hot) then gradually gets colder and colder until it's ice cold. If I play with the handle then it sometimes spurts a higher pressure like air was in the line, and then get warm again and repeat itself.

It seems to be just this shower. The plumber came over and he said he tightened the device inside of it and it should fix it but it didnt work when i took a shower today.

Should I just replace it?

FYI - this shower is the closer then our other shower to the heater. The kitchen which is the closest doesnt do this.

 

[havasu]

It may be a faulty "anti scold" valve. Replacement would be my first thought.

 

[leftheart]

does each shower potentially have one or is it a central location... Because all the other faucets work good, just that one..

 

[havasu]

Each shower would potentially have one, if so equipped. If they are a higher end or a newer shower valve, chances are they have them.

 

[leftheart]

So our well is sending up either calcium flakes or maybe gypsum flakes. Which plug the faucet and shower heads enough to decrease water flow, which freaks out the in-line heater thinking there is not enough demand or fast enough water use rate.. so it turns off and on. The reason why one would do it and not the other is due to the one with the issue was used more often and build up happens quicker. So i have been unscrewing the heads and dumping the flake build up. Now I'm Installing a softener with filter...

 

[phishfood]

Thanks for following up and letting us know what the problem was.