What is it?

[Grafunkus]

We had a Sealand 8600 with Bidet toilet in our aft cabin head. While tightening the connections we snapped the plastic check valves. This head is a discontinued model! We looked into getting replacement parts and decided to purchase a new head. Yesterday, we were at the boat and taking measurements, adding some shut off valves and other things. We have always known that this part was in the boat and thought it was a part of the head. Taking a closer look at it, we have no idea what it is or what purpose it serves, so before we haul it out, we thought we would ask here. It is attached to the water lines. Has an input line but no output. There are no identifying marks on it anywhere. Sorry the photos are all rotated 90 degrees clockwise. This is on a 3607.

[bud37]

Looks like an accumulator tank for the water system.

[km1125]

I agree with Bud. That looks like a fairly large one, but it's hard to tell the actual dimensions. I put one in under the aft berth on my 3607. They definitely smooth out the pressure variations on the potable water system.

That looks like one with a bladder (all the bolts around the 'top' where the hose connects to). That means it should also have a air valve to check and adjust the air pressure on the other side of the bladder. You adjust the pressure based on how your potable pump pressure is set.

Also, the way that's mounted you need to be concerned about draining it in the "offseason". Mine was mounted with the hose at the base and above the water lines so that it would always drain down into the water line so that water could be evacuated from the system. The way yours is mounted there's no way to get the water out of the tank, so it could freeze in the offseason (and it'll also be some stanky water after sitting MONTHS AND MONTHS in there!)

It looks like that's right inside the cabinet door and to the right on the port side of the aft berth. Am I correct? I'm wondering where that hose goes to when it goes "up"? I it's like mine, the potable pump is under a hatch in the bottom of that cabinet.

[Midnightsun]

Yep, agree about it being an accumulator. I do question the vinyl hose they used on that though. Definitely not up to spec for a pressurized water line. Should have used pex or other similar lines rated for water pressure. It is still rated at about 200psi however this is bursting pressure not working as opposed to pex @ 480psi. It's not like it is going to bust tomorrow but it is the weak link in the system.

That being said if it has been there for a decade plus, the bladder is probably dead and pretty much useless at this point. Just like tires in your car, they do need air addition/adjustment once in a while, not just install and forget.

[Viper]

Ya if the accumulator is still doing it's job, it'll minimize the amount of times your water pump comes on up to a certain demand. It also helps smooth out the pulses while it's pumping. If you open a faucet a bit and your pump doesn't stop periodically for a few seconds or so, then the accumulator is low on air. It either leaked out through the schrader valve (if applicable) or the bladder is shot. Look for a valve at the top of the tank. If there's one there, check the pressure with a tire pressure gauge. If it's zero, try adding air with the pump off and a faucet open. If you hear air coming out of the faucet, the bladder is toast and the accumulator is doing nothing.

[Grafunkus]

Thanks for all the info.

km1125 - that is exactly where it is located. However it is not mounted to anything at all. This is it pulled out of the cabinet.

20220626_110104.jpg

I don't understand where the air valve is located. Are you guys saying it is in the container?

I am sure the bladder is "dead". It almost looked like there was "dried" stuff in the lines. If the boat had been on city pressure, then this wouldn't have been required - correct?

[bud37]

Source of the post I don't understand where the air valve is located. Are you guys saying it is in the container?

Likely under that black cap on the bottom of the tank.

[Midnightsun]

If the boat had been on city pressure, then this wouldn't have been required - correct?

Correct, simply will aid in removal of pulsing pressure when using the potable water pump. Serves no purpose when connected to city water.

[Viper]

Ya look under the black cap at the top of the tank for the valve. If the tank is still okay, you need to mount it upright with the hose on the bottom and fasten it down properly.

[tomschauer]

As everyone mentioned, that is a pressure tank, just like one you would use at home if you had a well water (albeit a bit smaller). It seems it is not fastened in place, if so, lift it a bit, if it weighs more than a couple pounds the bladder is shot and the tank is pretty much useless, and you will soon see rust in your water. Don't bother to check the air pressure, it should only have to be done once at the time of install. You can replace it or eliminate it.
It should be fastened so it can't bounce around in your boat, but it can be mounted in any position.