Another sagging vent line

[mermike]

Hi all,

I think this question was answered, but I would like to confirm. There's no good reason to have a sag (or two) in a freshwater tank vent line, is there? We scrubbed the tank on a new (to us) Y33, and found water and sludge in the vent line. It shouldn't be too hard to straighten out, but thought I'd check before performing surgery.

 

[dlochner]

There are no good reasons for a sag in the vent line, especially near the tank and there are some good reasons for not having a sag. (same holds true for vents in holding tanks and fuel tanks)

A low spot in the line will allow water (or fuel or the other stuff) to collect in the line, effectively sealing the vent. Think of the trap under the kitchen or bathroom sink. The trapped water will allow stuff to grow and in the case of the holding tank, plug it up and permeate the hose adding to the smell.

Water enters the trap because the tank will get over filled or it is filled to capacity and the action of the boat sailing causes some water to get into the vent hose. Or, if the tank is filled with cold water and it warms, the expansion will cause the tank to overflow into the vent.

 

[Peggie Hall HeadMistress]

I couldn't have said it better...except maybe to add that it's a good idea to have an ARCH in fuel and water tank vent lines to prevent sea water from contaminating them if/when you're heeled enough to put the vent under water for more than just a brief dip. Holding tank vent lines should be as straight as an arrow...no dips OR arches.
--Peggie

 

[dlochner]

Thanks Miss Peggie, I've been studying, even spelled your name right.

While I have your attention, what's the hose diameter on a PHII from the pump to the bowl. I forgot to measure it last fall and I want to install a vented loop.

 

[mermike]

Much appreciated. My partner and I were both scratching our heads trying to figure out why it was done that way. I don't think it's possible to have an arch there without a dip, so we'll make it as straight as possible. I'll let you know if the patient survives

 

[Peggie Hall HeadMistress]

what's the hose diameter on a PHII from the pump to the bowl. I forgot to measure it last fall and I want to install a vented loop.

3/4", same as the hose from the thru-hull to the pump.
--Peggie

 

[dlochner]

3/4", same as the hose from the thru-hull to the pump.
--Peggie

Thank you.