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Onewheeler

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Posts posted by Onewheeler

  1. I have a similar problem. 4mm steel tank on our barge, too large to remove in one piece, it's wedged in between the generator and the engine, corroded beyond repair. I'm reluctant to use a cutting wheel as it's in the engine room and sparks and dust would go everywhere. Looking at cutting it up with a jigsaw, or maybe just cutting the top off and dropping a polyethylene tank inside it.

    Martin/

  2. If you've only got one vent pipe and it's going from under the bed via an airing cupboard to the roof, it sounds as if there's not likely to be much exchange of air to the tank.

    Smells develop if the tank goes anaerobic (assuming you're not using blue liquid which will make it stink whatever). You need to encourage as much air flow as possible, ideally by having two vent pipes with their outlets separated by as much as possible.

    Before we got rid of it, our holding tank had two 25 mm vents from either end of the tank with hull outlets about 1.5 m apart. Pipe runs were less than 50 cm each. No loo blue ever added and never had a pong even when pumping out.

    Of course you might also be getting pongs from your long horizontal run!

    Martin/

  3. 17 hours ago, Sea Dog said:

    Has anyone actually had a 'burst'?

    We had an implosion during a pump-out at a service point in Warwick. I think the bloke doing it must have managed to block the vent pipe. We only realised later when it dawned that the persistent stink wasn't from something industrial on the bank but from under the bed. No brown stuff in the boat but the blue liquid which he'd added had gone onto the floor. It was last thing on a Friday and the nice technical bloke at Elsan told us to use sodium carbonate to neutralise it. Not an easy thing to find in the next local shop - indeed, we never did. Mopped it out thoroughly with water. Had to sleep at the front with the doors open for a few nights and used a bucket found in the hedgerow for number twos and for the wife's needs.

    That was a rather crude tank which had been made from one of those blue industrial plastic drums. It was replaced with a sturdy polyethylene tank (available if anyone wants to make an offer, it's now in my garage) before that was taken out in favour of a portapotti.

  4. Yes, I was wary of the common statement that the Willis is usually used on a vented system. The one I am looking at is rated to 3 bar, which is adequately above our system primary pressure and the accumulator / expansion tank is plenty large enough to cope with heating up the water.

    Still thinking about it but there don't seem to be major issues that can't be resolved.

  5. Wondered if anyone has experience of using an external immersion with a marine calorifier. It would be nice to use shore power, and easier to plumb on our boat than installing an Essex flange [note to moderators: that's only rude if you have a filthy mind] on the tank. Is convective circulation likely to be sufficient or would a pump be needed? Thinking of using a 1 kW heater as our shore power capacity is only 6 A. It would take a few hours to heat up a respectable volume of water but fine if on a timer for the morning shower.

    Martin/

  6. Replace the bubbler fittings with a 1/4" BSP male to 12mm compression on the outlet side and a 1/4" bsp to 10mm fulham connector (or 8mm depending on what size hose you need for your regulator) on the inlet. More or less what I've just done. Use some liquid PTFE sealant on the BSP threads (Screwfix 5321J is good stuff). Ebay has all the bits: e.g. 120964642905 for the outlet.

    As said above, the ones fitted to the bubbler need a bit of force to undo: a good spanner and a vice are essential.

    Martin/

  7. There was a tale, of dubious origin, that someone was prosectued (1950s or 60s?) for stealing electricity from the Brookman's Park MW station of the BBC. The talke was that he had erected a resonant antenna powering part of his house at the end of his garden adjoining the transmitter site, and the engineers noticed a "hole" in the distribution of RF energy in that direction.

  8. 2.5 L / h is high unless you're going faster than most canal speeds. On our narrowboat we use less than 2 L / h (15 T displacement, 38 HP Beta) and most of our cruising is at about 7 km / h.

    We're just back from our month share in a converted oil tanker on the mainland: that's 35 T with a DAF 575.  From 300 km and 150 locks with 85 h of engine running, cruising mostly at about 9 km/h, we averaged 2.4 L / h.

    Martin/

  9. The Snug at Carnforth is wonderful, but quite restricted opening hours.

    In Lancaster the canalside White Cross is (in my opinion) much nicer than the Water Witch. Excellent food. Lancaster is full of nice pubs, and there's a wheelchair-friendly slope from most of the bridges in the centre.

    On the Glasson arm the Mill at Conder Green is a bit smart and foody, but still a nice place for a meal or a pint.

    The Plough at Galgate is easily reached from the canal: food is quite good, but I always found the beer rather disappointing. The New Inn just up and over the road from it is a nice "proper" pub.

    They should all be wheelchair accessible.

    (I've never been there by boat, but the boy-child was at uni there so we visit regularly)

    • Happy 1
  10. 2 hours ago, Midnight said:

    My inverter is pure sine wave. Where would I fit the heat sink and would I need one given that the pump never runs continuously for more than a few minutes usually less.

     

    Looking at the spec sheet you might just get away without one, but my preference would be to fit one. Either find a handy piece of *flat* steel to mount it on, or buy a heatsink from RS or wherever. If the heatsink is bigger in area than the device it should have a low enough thermal resistance for your application (unless you then wrap it up i foam!) You might find a CPU heatsink that could be adapted.

  11. 4 hours ago, Scholar Gypsy said:

    Does this suggest that your skin tank (or heat exchanger if you have one) is a bit undersized? I understood that the pressurization was to reduce local  boiling near hotpsots in the engine, not to enable the coolant leaving the engine to be much hotter than the thermostat rating? 

    Yes, it probably is, but at our normal speeds the temperature seldom goes into a region that gives me concern.  Pushing against a river in flood needs a careful eye on the temperature gauge though!

  12. 4 hours ago, Tony Brooks said:

    I do not see any need for thermal relief valve - if that means it vents the cylinder if it overheats.

    Many boats have thermostatic mixing valves fitted and unless you have a solid fuel stove the water transferring heat into the calorifier is controlled by the engine or central heating thermostat. This is why some marine engines with fresh water cooling may have a thermostat around 66C. Many boilers also have a safety cutout overheat thermostat.

    The engine thermostat does not control the coolant temperature if the thermal output from the engine is too high for it to control. My engine regularly goes way above the engine thermostat temperature as most of my cruising is at 8 - 10 km/h. I'm not in the market for a thermo/pressure relief valve, but where the engine coolant could exceed 100 C without raising an alarm it could be argued that there is a case for a combined parameter valve to protect the occupants from secondary side boiling. An engine temperature warning set at an accurate level under 100 C would be more useful: I am not convinced of the accuracy of the one on our engine although it should be under 100 C.  The pressure cap on the primary coolant is, according to the manual, 13 psi, which with antifreeze added could enable it to reach 124C before relieving. It therefore does not give significant protection to anything but the engine.

    Open to argument over whether a thermo/pressure relief valve improves safety...

    Martin/

     

  13. 22 minutes ago, Tony Brooks said:

    I don't fully understand what you are saying but ordinary "boat type" PRVs are available from 1 bar or less.

    We are discussing combined thermal and pressure relief valves. I've never seen one in a chandlers, or a DIY shed come to that. Lowest pressure available on a quick search is 4 bar, most are 7 bar or more.

  14. 1 hour ago, Mike the Boilerman said:

    No it's direct feed, known in the world of building as 'unvented', the same as a boat calorifier.

    I.E. no open vent pipe on the outlet discharging over a header tank.

    OK! I've never come across one before but it does seem a good idea. A quick search shows nothing available at under 4 bar, which is a bit high for many calorifiers. How many boats actually have one fitted? One could tee-off a separate PRV at a lower pressure rating.

  15. 42 minutes ago, Mike the Boilerman said:

    On a household system there will be two PRVs. One in the cold water supply to the calorifier, and another connected directly into the calorifier. The second is actually a "temperature and pressure regulator", and also opens if the temperature in the calorifier rises above 90 degrees C. 

     

    Is that not for direct feed systems only, or am I behind the times? (It would not be unusual!)

    Are the plastic containers indicative of where the leaks are coming from? It looks from the slightly fuzzy photo as if there is a bead of water on the tee-fitting above the white container.

  16. I have similar, it works fine. Mine has an external shunt. Only minor grumble is that with low loads which should be within the resolution of the current metering it doesn't register. Planning to investigate further this week. It's fascinating to watch the Webasto consumption changing through its cycle.

  17. 36 minutes ago, nicknorman said:

    Anyway, I presume you are plugging the IT into the shore bollard first, then plugging the IT into the boat or otherwise switching on the boat's supply (e.g. at the consumer unit) - if there is no load on the transformer output then obviously the peak current will be minimised.

    Not obvious at all. If you happen to make the connection at zero degrees phase the current into the transformer will be maximum. The minimal load usually connected is of minor significance.

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