I have a shower that frequently loses pressure on the hot side.

This has happened around 10 times in the last 5 years.

Each time I have to have a plumber come out to look at it for $150 or more.

Usually, installing a new Moen cartridge fixes it, but sometimes a new cartridge does nothing and the valve itself has to be blown out by turning on the water with no cartridge installed. The shortest amont of time a fix has lasted is less than 24 hours and the longest a fix has lasted has been 2 years

The last time it was fixed was this Monday and less than a week later, the issue is back. The plumber thinks a new valve might fix it. However, “might” is not a good enough answer for a job that may cost over $1000 after paying both the plumber plus a tile guy to repair the hole the plumber cuts to access the valve.

I was thinking maybe there is debris in the hot water line (maybe solder from the hot water heater), but wouldn’t other faucets in the house get clogged then or are shower valves just more prone to get clogged by any debris?

I would hate to pay the money for a new valve and tile repair and then a week, month or year later, the same issue is back with a new valve.

If I get a new valve, I would get a different type that lets me control temperature a flow independently, but I don’t want to waste the money if the issue is not a defective valve.