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Post by lollygagger on May 10, 2017 9:46:02 GMT
Yes, me again.
I'm trying to work out why my hot domestic pressure release valve is filling up the engine bilge. It didn't do for the first 6 months I had the boat.
I think I may have inadvertently dislodged the end of the pipe which then fell into the bilge so I've been looking for where it may have been connected. There's no suitable skin fitting for it and it's not long enough anyway.
Last night it occured that maybe it connects to the rear deck drains. The main ones are just holes at deck height, but there's a hatch in the middle with drainage for the gaps. You can see in the photo these gutters drain into a piece of vertical box section. This is where it gets confusing and someone might know the answer - I can't see where the bottom leads to. If it was straight through the hull I'm pretty sure I'd remember seeing them when it was out for blacking.
I'll post pic in a mo...
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Post by lollygagger on May 10, 2017 9:48:19 GMT
Excuse the mess, I'm working my way front to back and only just got here. Got to get it dry and sort the overflow to keep it that way first.
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Post by lollygagger on May 10, 2017 9:53:34 GMT
The end of the pipe is the black one tied to the green one in the centre of the pic, directly below the drainage box section. It would reach which is why I'm looking, but as yet I can't see how it could have drained into it.
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Post by bills on May 10, 2017 10:08:25 GMT
In any case, I don't think you should be losing much from the valve unless it has developed a leak.
Unknown to me, my hot water pressure release valve was teed into my shower drain, but upstream of the gulper pump. When it developed a slight leak, the shower tray would slowly start to fill, but only when I was on the boat. That caused a lot of head scratching until I finally worked out what was going on!
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Post by lollygagger on May 10, 2017 10:37:30 GMT
In any case, I don't think you should be losing much from the valve unless it has developed a leak.
Unknown to me, my hot water pressure release valve was teed into my shower drain, but upstream of the gulper pump. When it developed a slight leak, the shower tray would slowly start to fill, but only when I was on the boat. That caused a lot of head scratching until I finally worked out what was going on!
Perhaps that's the answer. I have mucked with pump and although I reckon I have the pressure set lower that it was, so it only just kicks in to keep the shower running, the pressure it builds to isn't individually adjustable and may now be higher - skanky shurflo pump. A bit of expansion then increases pressure enough to operate the valve. That makes sense. Meanwhile I've poked down the holes which do indeed continue down to the canal, I can't think how I missed them, but there's nowhere to connect a pipe. I'll fit a skin fitting for future disaster staving and sort the pressure, which I do know is higher than the release valve is marked. New pump or better pressure controls externally? That is the next question.
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Post by lollygagger on May 10, 2017 10:41:26 GMT
Maybe I should dismantle the pump pressure switch. Could be gummed up with limescale and making too bigger difference between on and off pressures? It does seem to have trouble deciding when to stop pumping and often has a few more bursts after first switching off.
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Post by tonyb on May 10, 2017 15:19:59 GMT
I consider the built in pump pressure switches only toys. Fit a Square D external switch and you can adjust both the cut in and cut out pressure to suit.
Its hard to see but the steel the deck board sits on looks like a right angle to me although it may have an kick up on its outside edge. I think it may leak rain into the bilge, especially if it of the boat trims up by the bow.
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Post by lollygagger on May 10, 2017 16:00:32 GMT
I consider the built in pump pressure switches only toys. Fit a Square D external switch and you can adjust both the cut in and cut out pressure to suit. Its hard to see but the steel the deck board sits on looks like a right angle to me although it may have an kick up on its outside edge. I think it may leak rain into the bilge, especially if it of the boat trims up by the bow. I see what you mean Tony, I'll tip some water in the channels and see what happens. However, I'm sure it is the pressure relief filling the bilge, I've watched it do it. Meanwhile, with nothing to loose and following random advice on the internet (I know, I know) I've drilled out the teeny hole inside the pump that feeds the switch to see if it makes it better. It was about 0.5mm, now 1.5mm as I couldn't find a 1mm drill. I realise the hole is deep and small to damp the action, so maybe it'll go bananas now, but I won't have lost anything by trying. Next step external switch, I read your Square D recommendation elsewhere and looked on Midland Chandlers as suggested but without success, it was a 10 year old thread somewhere. I'll look harder if the hole drilling doesn't work.
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Post by lollygagger on May 10, 2017 16:51:34 GMT
Done and tested after turning the pressure quite a bit lower as well it kicks in more quickly of course because the accumulator isn't so full, but passes the continuous shower test with ease.
After I've eaten I'll put the pressure gauge on an see where we are. I plan to turn it up to get better use of the accumulator but keep it under the release valve pressure.
Relief valve is 2bar, so if I set pump to say 1.75bar, does that sound about right?
I have the end of the release pipe in a bucket now so I can monitor my success or otherwise when I heat the water up.
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Post by lollygagger on May 10, 2017 16:54:41 GMT
I think the teeny hole inside the pump is for systems without accumulators to prevent rapid cycling when a tap is running slowly. Not needed with an accumulator?
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Post by lollygagger on May 10, 2017 16:59:48 GMT
I hate plumbing.
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Post by lollygagger on May 10, 2017 17:24:30 GMT
Now at 1.75 bar, heater on, pipe in bucket, won't run the hot tap while it heats up.
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Post by Deleted on May 10, 2017 17:28:27 GMT
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Post by Deleted on May 10, 2017 17:35:37 GMT
Add me to the list.
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Post by JohnV on May 10, 2017 17:39:14 GMT
ditto for me as well
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