Our selection includes pipe adapters, twist-on valves, 90-degree elbows, side valves, waste valves, and many more. Otherwise, a 17/32” orifice will simulate the. I run to home Depot and buy a hose bib with the same thread. Airstream Lead Free Low Point Drain Valve is made of brass and has a 90 degree turn, 1/2' barb fitting, and a 1/4' male pipe thread. Low point drains hook to the water lines inside the unit. Drain the water heater via access valve on the outside of the RV near the kitchen. The valves on the outside of the RV are likely to have ‘black’ and ‘gray’ labels. They are located near the city water connection (valve shown open in the photo). The other one allows the “stem” to move up and down but for some reason it will not snap closed. One valve when pushing down snaps shut as it should. This tank will have it's own Waste Gate Valve to drain it.

The manual says to 'Drain system by opening faucets, low point line drains, and removing water heater drain plug. Here’s an illustration of the shower drain and vent line plumbing: Drain the fresh water system: Open all exterior low point drains. Not much came out and the tank was 3/4 full. For Jayco Motorized product: Move the valves to the “Sanitize/Winterize Lines” position. Most Trailers have a drain for the FW tank that is located very near the FW tank. I have temporarily carved a piece of wood to slip over what is left and operate the valve, but would like to replace or upgrade the original. In order for the relief valve to crack open, the following inequality must be satisfied.Rv low point drain valve size Shut the valves and remove the drain plug from the water heater. The “cracking pressure” is a required specification for each valve type. Cases 2 and 3 both relieve directly to ambient conditions (ie, the atmosphere) and hence, an exit pressure (ie, the ambient pressure) is required as an input. Note that there is initially no flow in the pipe downstream of the valve until the relief valve cracks open (the pipes are assumed to be 100 % full of fluid and not empty).

In cases 1 and 1a, the relief valve is relieving into vent piping downstream of the valve.

There are three types of relief models available: Internal (Cases 1 & 1a), Relief Valve at Exit (Case 2), and Inline Exit (Case 3). The required inputs for modeling a relief valve are the valve type, cracking pressure, valve loss model, and the exit pressure in the case of relieving to the atmosphere. Relief valves can be modeled in four different configurations with AFT products and they are shown in the figure below.

Relief valve sizing cases