Any tips on the tankless water heater

If you do a search you will get a lot of hits.

tmmar
We have a Precision RV 550 in our coach shown below. We like the tankless system but it has taken some getting used to. The plus is that you cannot run out of hot water. There are several things to know about the system:
1. Pressure- You must have good pressure for it to operate. We rigged up a Watts home style pressure regulator which we hook up at the faucet. We maintain 50-52 pounds of water pressure through the regulator. A 45 pound RV regulator bought in a RV supply store WILL NOT WORK.
2. If a park has low water pressure fill the fresh water tank and run the pump.
3. The temperature is controlled by the flow rate at the water heater. There is a valve at the heater where the adjustment can be made. With good pressure and the right flow rate you will never run our of very hot water.
Good luck

Wish i could help. I have an Atwood and seems to be ok so far but generally you will probably have to balance incoming water temp with flow. As far as the 40 psi you have, where are you measuring it. And is it still 40 with the faucet open. I would at least try it with the filter and regulator removed. I think you have see if it is getting cold because the burner goes off or runs out of capacity. If it is capacity, close the valve a little. If the burner cuts off because it is too hot, turn the hot water on on the sink at the same time. If it then stays hot, remove the restriction in the shower head. My guess is it's getting too hot. Also, if it is getting too hot you might be able too turn the gas pressure down a bit. The problem is that the flow requirement changes with the season.
Good lick and let us know if you solve it or throw it out.

I have seem some RVs I think Jayco has some models with tank less heaters

I have looked into it. Only thing I can find out is they don't work very well in an RV situation. But of the ones that don't work some work better than others
:-)