Hot Water Heater Drain

[denpooch]

Hey there.
On my 2005 Mariner there is a thru hull 'drain' for the hot water heater.
Does anyone know how to have the unit drain through that plumbing? It's there, I just can't figure out what combination of 'valves' leading into the heater will make it happen.
in the past I simply open the spigot on the heater, lift the pressure release and the water flows onto the deck.
It would be nice to use it as designed but don't know how.
Thanks.

[Midnightsun]

in the past I simply open the spigot on the heater, lift the pressure release and the water flows onto the deck.

Thats how it is supposed to be done, nothing more. It can happen that deposits start to plug the drain hole so you may need to remove the valve and run a wire in there to flush out the crud a little. Obviously take care to do this when the heater has been off for quite some time to avoid burning your hands.

[denpooch]

Hans there is no drain hole. The water just runs forward on the deck and into the sea.
It's odd because a diagram in the owners manual details 'water heater drain'.
I wonder if it has to do with a specific combination of the three 'on-off' valves. There is the cold water 'into' the unit. A hot water 'out' and also a 'bypass' valve which I turn on when draining the heater. This bypass allow me to get by using just a couple of gallons of pink instead of filling up the heater.
Thanks for your input.

[Viper]

The three valves on the water supply lines are for a by-pass system so the unit can be by-passed when winterizing or servicing. On a Mariner with the water heater under the helm, I've only ever seen them drain onto the floor and down the port side stairs to the bridge. Some Mariners have the water heater under the bench in the salon but I've only seen them drain into the bilge. A new practice is to have the pressure relief discharge overboard for safety reasons but that's a newer thing, pretty sure not the case on a 2005.

[Midnightsun]

QR_BBPOST Hans there is no drain hole. The water just runs forward on the deck and into the sea.
It's odd because a diagram in the owners manual details 'water heater drain'.
I wonder if it has to do with a specific combination of the three 'on-off' valves. There is the cold water 'into' the unit. A hot water 'out' and also a 'bypass' valve which I turn on when draining the heater. This bypass allow me to get by using just a couple of gallons of pink instead of filling up the heater.
Thanks for your input.

The 3 valve bypass is rather common on most boats however this will not drain the heater and is used exactly as you described to bypass the water heater when introducing antifreeze. How are you draining the water heater with no drain? Not following you on the "water just runs forward on the deck and into the sea".

[denpooch]

I mention 'the water just runs....'
The water heater is forward behind the 'rumble seat' on the bow of the boat. When I open the spigot and release the pressure valve, the water runs forward (Mariners list slightly forward due to 150 foot chain in the anchor locker)
and 'off the boat'.
Thanks to you and Viper. I will proceed as usual.

[bud37]

On that same boat ( earlier year ) with the AC unit behind the seat and the water heater under the salon bench port side.... there were two drains.......condensate and the raw cooling water from the AC unit.....that one went out the port side hull about mid ships......perhaps the hose and fittings are all there but not used....have a good look on the port side, ya never know. I know your boat has the redesigned salon.

Yes there is no way the water would drain anywhere but down the deck to the bow considering the deck slope.

[denpooch]

Done!
Open the spigot...release pressure valve and walk away.
Bypass the heater, add 2 gals of pink into fresh water system, run pink out of each faucet. Force pink thru 'city water' input and the fresh water system is ready fo hibernation.
Ran fresh water through A/C system. Forced pink til it came out of both thru hulls and done.
Engines this weekend.
Thanks again guys.

[Midnightsun]

After all these years of fighting with a drill pump that never seems to work to force the pink stuff into the city water inlet, I finally had a revelation. I forgot to bring the drill pump and was stuck so my tiny little brain had to work a bit. It was so obvious I guess I never thought of it, KISS. While introducing pink into my wash down via the on board wash down pump, I simply connected the wash down spigot outlet with a hose to the city water input. Why in the world did I never think of this before, so easy. In my case the wash down outlet and city water inlet are only a few feet apart, easy peasy.

[bud37]

Did it that way for years, .....it works just fine and is quick, just one caveat to mention and if all are aware then they can proceed how they want.

What ever little organisms are swimming around in the raw water side you will introduce to your fresh water side by pumping this way.......we never used our fresh water system for drinking even though it was sanitized in the spring at start up.....so be aware. If unsure, a fresh water test sample can be taken and analyzed to ensure safety.