propane instant/tankless water heater

mchammer

Hi all,
I'm looking at an off-grid project at the moment and trying to factor in my power requirements and came across this product which seems to be quite widely used in the USA. It's a Liquid Propane Instant Water Heater which is very efficient and would reduce my power requirements and setup costs significantly if I was able to use gas to heat my water. The equivalent electric instant water heater usually consumes around 9kw/h. The property will not be occupied except for weekends and the odd week here and there.
I was just wondering if anyone has used this kind of system and if they would recommend it or if anyone knows any reason why it may not be suitable for use over here.
Many Thanks
MC

Markcheese

Hi, can u give a few more details and possibly a link.
I'd be interested in it and could run it past my dad who's a plumber...
Would be a bit concerned if it doesn't have a flue or something, might be only suitable for an open shed or something.
Think falling asleep in front of a super ser(carbon monoxide) . Cheers

zagmund

I remember in the old days in my grandmothers house there used to be a water heater (broadly) like what you described. I'm sure they are still around.

It was basically a small tower with a burner underneath. When you turned on the hot water tap, you could hear the burner ignite and within 2 or 3 seconds you got hot water. I'm sure there were all sorts of health & safety issues, but no doubt efficiency, technology & venting solutions have moved on a long way since it was fitted back in 1940.

I always thought it sounded like the most efficient solution for water heating - just heat exactly what you needed. If you needed a bath, you just heated *exactly* the amount of hot water that you required and not a drop more. If you needed a basin of hot water 30 minutes later all you had to do was turn on the tap, wait 2 or 3 seconds and you had all the water you needed. No need to store anything and lose the energy over time.

z

doubledecker

I've a few over the years like this one::
http://www.ebay.ie/itm/NEW-12L-GAS-LPG-PROPANE-TANKLESS-INSTANT-HOT-WATER-HEATER-BOILER-STAINLESS-/320832621099?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item4ab31d4a2b

popular in the campervan world... most camper stores can order them in... I'd steer clear of the ebay ones from china/hong kong... not as robust as others...
They work fine, and seem safe enough..... the flue needs a decent 'draw' for the flame to stay lit... and should def. be 'flued' to the outside...

the only bother with them was dealing with the cold conditions... very narrow copper pipes inside and one I had cracked in the cold weather,, even though it was drained.. now I pump the water out every winter and wrap it in insulation... so if you were using it only the occasional weekend, you'd have to drain it every time... or make a plan of a insulating blanket of some sort to completley cover it while you're away...

eth0

Stay away from ones with a pilot flame, huge waste of gas. We used to call this type of device a 'geyser'

This crowd would make fairly decent ones I'd say. There are ones with battery powered ignition or from water pressure.
http://www.nefit.nl/consument/producten/geisers/Pages/Default.aspx

jinghong

you could always build a small biodigester and use the gas bleed for cooking and water heating, powered by your food compost
http://www.ideassonline.org/public/pdf/BrochureBiodigestersENG.pdf