Do remote / inline pressure balance valves work well? Alternatives?

I'm looking at various exposed tub fillers with hand shower. I haven't talked with county inspections yet but anticipate needing an anti-scald device to meet code. Very few of these have thermostatic or pressure balance valves...that would be incompatible with the 'classic' look anyway.

I'm seeing recommendations to use something called remote inline pressure balance valves, like the Grohe 35204. Do these things work?

Installation instructions are hard to track down but from what I can tell they aren't adjustable, even internally, and work by shutting off flow altogether when a pressure imbalance occurs. Since there appears to be no adjustment, I'm concerned whether I can get a good flow of hot water when I want a hot bath; also whether these severely restrict flow, or are otherwise problematic.

Is there a better alternative for this application?

If the remote pressure balance valves are an issue, one potentially hare-brained (non-plumber / engineer) idea I had was to use a thermostatic valve on the tub filler's hot line only, set it on the highest internal setting, and install in an out-of-the-way location. That would still give me the 'classic' look with hot and cold running water that's also temperature limited. Not sure if that meets code though.

Appreciate folks' ideas.

Valves come in various sizes, where 1/2" and 3/4" are the most commonly available. A 1/2" supply line can source about 5-6gpm safely. A 3/4" valve over double that. If your supply lines aren't larger all the way, a larger valve will have little effect (some, though) on the available flow. A pressure balanced valve will have no effect on the flow unless one side's supply pressure drops, then it compensates to try to retain the balance of hot/cold, which means slowing the flow to the side that still has higher pressure. The internal design of each valve differs, so look at its design flow in gpm, then choose one that meets your needs. Under normal conditions, it shouldn't reduce the flow below that figure (but note, that figure is based on your water pressure at a certain point, flow will change some as it either increases or decreases from the test value).

Like anything mechanical, it will eventually need service, so don't put it burried behind a tiled wall unless you have access in some manner that doesn't destroy your tiled wall.

They do NOT need adjustment. When the pressure drops in one line they automatically adjust the other one to the same level. They only "shut off the flow" when either the hot or cold water supply is turned off. One problem with them is that they have very small internal ports so they do reduce the volume.

Most valves do not maintain the same port size as the inlet pipe, so putting a pressure balanced valve in there may not make any difference in total available flow - nearly any tub/shower/sink valve will flow less than the supply pipe could straight through (so, adding a pressure balanced valve in, may not make any difference). Look at the spec sheet to see what the one(s) you are interested in can flow, and then, the only reason it should drop is if it is doing its job because the pressure is different between the two inlets.

Thanks guys. From what I'm reading here, a "remote" pressure balance valve is really no different than pressure-balance part of the ones I'm more familiar with that also have a mixer. That's what was confusing me a little. Good advice to make this accessible - moving part subject to wear and residue, so will eventually need service.

I've used them a few times, generally when a client remodels without a permit and gets tagged by the building department.
They make a great alternative to replacing the tile.

Work great and recommend them highly

Michael