I have a Girard tankless that was installed when we bought our 2021 Jayco Alante. It works like a champ.
It did take some getting used to how it operates as compared to a tank heater.
The tankless requires a certain amount of water psi to produce hot consistent water. Under psi results in the flame turning off (as a safety precaution) or sporadic flame and you get the cold blast shower, and trust me it’s really frustrating. It had me cussing up a storm like the retired sailor I am.
Over psi is too much water passing over the flame and doesn’t give the water enough time to heat up.
I decided to use the installed water tank on the RV and use the water pump which magically produced the correct amount of psi…35 psi. Once I figured it out it works like a champ everytime.
Prior to using the installed water pump, we used the city water hookup. I would check the psi at the connection and it would read 40psi or so. Well, 40psi at the connection doesn’t mean 40 psi at the flame of the tankless heater and that was the problem. Not enough psi at the tankless flame.
When we turn the shower on, it takes about 15-20 seconds and we have hot water. It uses LP so remember to turn that on AND the on/off switch on the heater or you’ll have another sailor potty mouth moment…again.