Fresh tank inlet

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nisseven
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Fresh tank inlet

Postby nisseven » Thu Oct 08, 2015 10:34 pm

How strict are the rules?
" Fitted with an inlet of not less than 25 mm diameter, and has a cap or seal to
prevent foreign matter entering the tank;"
This wording appears in the rules, my tank maker, who seems to be well respected and has made lots of tanks, advised me not to put a direct inlet in the top but to pressure fill via a hose connection. The inlet will in this case only be 15mm?
Also what is the device that is to be fitted to the breather to stop foreign matter from getting into the tank?
Thanks for any advice
Bruce

beanpole
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Re: Fresh tank inlet

Postby beanpole » Fri Oct 09, 2015 8:50 am

4.1.3 (b) of the NZ Standard. "Should the tank be pressure fed,12 mm diameter is acceptable."
For the vent, the best is to bring it up somewhere and turn the pipe downwards. On the end use a piece of plastic fly screen material over it and hold it on with a cable tie. This is to stop the creepy crawlies going for a swim in the middle of the night.
Gordon

nisseven
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Re: Fresh tank inlet

Postby nisseven » Fri Oct 09, 2015 12:29 pm

Thanks Gordon, that will do me
Bruce

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Doit
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Re: Fresh tank inlet

Postby Doit » Fri Oct 09, 2015 12:57 pm

I added an outside tap between the fresh tank and the pump so I could fill direct from a hose. It has the added benefit of being to empty the tank and rinse feet, fill dog bowl etc.
Trevor
NZMCA member, 2005 Canter 3.6l. 370w solar. 220AH Gel house,195l Fresh/150l grey. VSR,12v Equaliser charger, 7 stage 240v charger, 1000w mod sine inverter, 300w pure sine inverter, 12v Vitrfrigo 90l fridge. Webasto diesel heater. Thetford WC.

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NeilV
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Re: Fresh tank inlet

Postby NeilV » Fri Oct 09, 2015 9:06 pm

This sounds ideal to me too! I already have a mains pressure fitting to my system as we're currently living aboard while awaiting a house build, but used a one way valve to stop the tank overfilling, and then needed to add another 1way to the pump output as the mains pressure wrecked my pumps pressure switch too. :roll:
How do I stop the pressure fill from negatively affecting my pump though? Sounds like I'll need a tap to allow the pressure to the tank?
8.5m 1990 Dennis Dart bus, 6L turbo -4 pax
- 24v system: 2x 104ah AGM, 20a PWM controller 500W solar; 1200w puresine inverter
120L grey/fresh water, 75L compressor fridge, gas Califont, Diesel MK85 heater [awaiting install]

beanpole
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Re: Fresh tank inlet

Postby beanpole » Sun Oct 11, 2015 2:33 pm

Sorry I missed this one Neil, I was away to the Board meeting in Invercargill.
There is quite a difference with a "mains" filling system and a "full" mains pressure system.
Any mains pressure system should be kept totally separate from the tank and pump and just go direct to the taps and so on. If I recall you have an externally mounted califont so this may be vulnerable to excess pressure.
If you wish to have a full mains system, this would need to be done by installing taps to isolate the vulnerable lower pressure items from the mains pressure.
Gordon

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NeilV
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Re: Fresh tank inlet

Postby NeilV » Sun Oct 11, 2015 3:32 pm

Thanks Gordon,

My Califont is mains capable and the pump is now protected by a non return valve (as is the mains pressure hookup point) thus allowing me to simply turn off the pump when hooked to mains and continue with "unlimited supply".

If i wanted this to be a "mains filling" system also, would I then just add a T junction from mains inlet to tank inlet with a tap to regulate flow, or is there something more needed?

I have 122L tanks from TTPlastics with a 50mm->25mm inlet, 15mm breather and 15mm outlet to the pump filter.
If I Teed in a 15->25mm join on the inlet pipe, would the 15mm breather suffice for pressure reduction at full mains injected flow rate?
Last edited by Mark on Sun Oct 11, 2015 6:27 pm, edited 1 time in total.
Reason: Redundant quote of immediately prior post.
8.5m 1990 Dennis Dart bus, 6L turbo -4 pax
- 24v system: 2x 104ah AGM, 20a PWM controller 500W solar; 1200w puresine inverter
120L grey/fresh water, 75L compressor fridge, gas Califont, Diesel MK85 heater [awaiting install]

beanpole
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Re: Fresh tank inlet

Postby beanpole » Sun Oct 11, 2015 9:00 pm

For the mains filling system all it needs is a tap to the tank to manually turn on to fill and off when full, teed in as you suggest.
If I read you right, I would be very wary of the tanks sustaining mains pressure for too long. But then if that was so, there would need to be a tap on the breather to retain pressure. ??????
Pressure reduction can only be achieved with a pressure reducing valve. Reducing the diameter of a pipe only reduces the flow as the pressure will eventually equalise throughout the system however small the pipe is.
Gordon


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