draining hot water tank

Be sure to flush out the Water Heater after draining. I use a wand-like device called Tank Saver from Camping World. Some make their own.
It gets the calcium/lime deposits out of the heater better than draining alone.

Matt_Colie wrote:
Hey Guy,

What nobody had out ans said is that you can't use the RV's water pump to clear all of the water out of the system. You need to either come up with at least a small air compressor (~ 3CFM @30PSI - a liitle 12v tire pump just won't make it) or set your pump up to pump RV (drinkable - watch out and read the label) anti-freeze into the system. If you don't do one of these to completion, there will be water left in low spots where it can freeze and break things. (The valve in the toilet is a favorite ~45$ for the parts).

Matt

I think everyone was saying you can't use the water pump to blow the lines out. There is a drain on the water heater and there should be low point drains in the supply lines that will drain most of the water out.

You're right though, no one mentioned using a compressor or RV antifreeze to remove the rest of the water. You also need to dump some RV antifreeze in all the drains to remove the water from the traps.

Hey Guy,

What nobody had out ans said is that you can't use the RV's water pump to clear all of the water out of the system. You need to either come up with at least a small air compressor (~ 3CFM @30PSI - a liitle 12v tire pump just won't make it) or set your pump up to pump RV (drinkable - watch out and read the label) anti-freeze into the system. If you don't do one of these to completion, there will be water left in low spots where it can freeze and break things. (The valve in the toilet is a favorite ~45$ for the parts).

Matt

Thanks my fellow camper friends! i understand now. You folks always come thru with solutions and answers. Happy Trails!!:)

The pump (and city water connection) put water into the cold water lines....and into the bottom of WH (cold inlet). The pump can not suck water out of WH.
The WH cold inlet is on discharge side of pump.

Depending on size of your WH....you could have 6 to 10 gallons of water in the WH tank.

Another way of looking it is the pump pushes water through the system. When the tank runs dry it mostly pushes air. It can't push enough air to drain the heater especially since the water heater discharge is at the top (hot water rises.)

Better to just open the drains on the water lines with the pump off. Open all the faucets inside and the water will drain out on it's own. Remove the drain plug on the water heater and let it drain. As mentioned the pump won't blow out the lines very well and certainly not the water heater.

The water pump sucks from the Freshwater tank and pumps into the hot water heater. The pump keeps the hot water tank full, it doesn't empty it. You stopped getting water out of the faucets because the pump ran out of water from the freshwater tank.

The only way to empty the hotwater tank is to drain it and that can be 6 or 10 gallons of water depending on your size.

The pump can only pump as long as the pump has water coming into it. Once air gets into it it doesn't do very well. Even if it did it could only pump out the water above the hot water outlet which is at the top of the heater.

Better to set the bypass valves and then drain the heater. I use a hose to siphon what is left in the tank after it drains.

I am thinking the outlet for the hot water is at the top of the tank.
Hot water rises and cold sinks, so they probably do not have the outlet to close to the bottom of the tank.
Thus when the hot water tap is open it will draw from the tank only down to the level of the outlet, thus leaving water in the tank until you open the drain at the bottom.
Also when you open the drain you should open the relief valve also to allow air into the tank to help it drain.