We have a roman faucet in our jet tub. The hot water side starts hot then goes to cold after a short time. If I turn off the faucet and turn it back on hot water comes out again and only lasts for about 10 seconds.
By the way, we can get hot water out of everyother faucet/shower in our house this issue is only with the jet tub faucet..?

Do you have a mixing/tempering valve on the roman tub faucet? If so, I would start there.