H34 Water Tank Mystery

[Joe Mullee]

Let me set the stage. There are two water tanks on the H34 with the aft tank sitting higher than the forward tank. There is one pump servicing both tanks with a selector switch used to pick which tank is used. The pump is located next to the lower forward tank. One tank does not feed into another. I do not have a system to check the level in the aft tank and there is no easy access to it. In the forward tank I installed an inspection plate into the top so I could check the level in that tank. I filled the aft tank to the top but only filled the forward tank to the 2/3 mark.

I left the boat for a week. When I came back the forward tank was filled to the top. Did I screw up and mistakenly fill the forward tank more than I thought? I emptied the forward tank again to the 2/3 mark before leaving the boat for another week. When I came back it was again filled to the top.

I checked the filler cap and ring for the forward tank and they are in good shape. There's no water in my bilge nor leaks in my boat. I'm going to see if I can add water to the aft tank to see if that could be the source. I don't know where else the water could be coming from. Is it possible that the pump is failing and allowing water to pass via gravity from the higher aft tank to the lower forward tank?

Any thoughts are appreciated.

Thanks,
Joe Mullee

 

[Stu Jackson]

Joe, we have the same arrangement. If both valves are open, the aft tank feeds into the forward tank. I haven't filled the forward tank from the deck fill in 15 years. I open both valves, then fill the rear tank. Then I close the forward tank valve, and use the smaller forward tank as backup. When the aft tank empties I know I need a refill, and I fill the aft tank again with the valves both open. Never need a tank level gauge.

It's most likely not the pump, 'cuz the pump's on the outlet, not fill side, of the tanks.

 

[kloudie1]

Selector valve is probably leaking, Joe.. Mine got bad enough that it would suck air from the empty tank and do a lot of spitting at the faucets. The valve is easy to rebuild if ya feel like playing.. and it is an easily available part
On mine, the spring inside had rusted and the debris had scored the seats for the tapered plug. I found a stainless spring and carefully re-seated the valve .. has been fine again for 6 years..

EDIT: some folks replace the little three way valve with two valves on a tee so that there is more positive control of which tank is feeding and provides a better isolation.. There is no stop on the original three way so it can be confusing as to what is on and what is off ..

 

[splax]

OK, so how do you fill the forward tank? I just filled the aft tank twice last week and hadn't looked into filling the other tank.
How are you supposed to clean them? My boat sat for years before I got it and I really don't know what would be the best way to get reasonably clean water from the tanks.

 

[kloudie1]

Splax, on my '85 model, the forward tank fill is on the port side just forward of the chainplate .. the tank is under the port settee .. on mine the aft tank fill is under the hinged teak plate where the emergency tiller goes.. you can see the cap next to the toe rail .
EDIT:
The process for renewing the tanks issomewhere on this site..Was posted by user named Headmistriss. Peggy wrote a very clear and detailed post to accomplish that. I don't have it at my fingertips .. involved treating with bleach waiting, pumping down then a rinse out.. Good Luck.

 

[Stu Jackson]

Fresh Water System Recommissioning 101 http://c34.org/bbs/index.php/topic,5836.0.html

 

[splax]

Thanks for the information and the direction.

 

[Joe Mullee]

Thanks Stu & Claude. I'll check out the valve.

 

[splax]

I filled my Port tank and cycled the valve. I think it is bad since water would not flow when the arrow pointed to the line from the Port tank. ??

 

[kloudie1]

H-34 Tank Selector Valve

Splax, the valve is a bit wonky .. Mine is original, I think and is plumbed so that the pump suction is from the top fitting. Port tank is left side and aft tank is right side when looking at the handle.. When the arrow is pointed up, it connects pimp suction to port tank. When pointed to the right, it connects aft tank to pump suction.
The picture of the installation shows it with the the port tank selected

 

[Stu Jackson]

Claude, is there a position that both are open? I ask, 'cuz we have two separate simple plastic gate valves (OEM), so I can easily tell which is open or closed and can close and open both. As I mentioned, by opening both, I can fill both tanks from just the aft fill.

Also, your earlier post mentioned using two separate valves, which is simply what we have. Two ball valves would do the trick.

 

[splax]

Looking more closely, I saw the original owners wrote valve instructions in black magic marker on the fiberglass hull under the setee'. A both position would be nice since the aft tank would empty first, but being forced to select tanks makes you pay attention to boat trim and if a tank should spring a leak you don't lose the contents of both.

 

[Stu Jackson]

A both position would be nice since the aft tank would empty first, but being forced to select tanks makes you pay attention to boat trim and if a tank should spring a leak you don't lose the contents of both.

The Both position is ONLY used for FILLING the tanks from one source/fill line. Not for when in use. Kinda like the B position on a 1-2-B switch: ONLY when charging!

 

[Allan12210]

That three way valve only has a one or the other or both off position. There is no both on choice. The pump suction is from the center tap of the valve and the two tanks feed the outer taps, respectively. The valve rotates only 90 degrees to switch tanks. After 28 years I still turn it the wrong way when I switch tanks and I get no water. I like the dual valve idea. Its on my list of projects.

 

[Claude L.-Auger]

Looking more closely, I saw the original owners wrote valve instructions in black magic marker on the fiberglass hull under the setee'. A both position would be nice since the aft tank would empty first, but being forced to select tanks makes you pay attention to boat trim and if a tank should spring a leak you don't lose the contents of both.

I replaced the exact same valve last year (+/- $15) and I also used a marker on the fiberglass. Positions on mine are the same as Splax and there is not a "both" position.

 

[kloudie1]

Since the tanks are so far apart (maybe 15 feet of pipe), and are connected by small pipe, it would be difficult to fill the front tank from the aft without waiting a few hours.. but if allowed to gravitate....., the bottom of the aft tank is about the level of the top of the port tank.. so they'd try to equalize. A leaking three way would let this happen.