15 hours ago, rectangularBuilding said:

I just "discovered" the LPG tankless (inline) water heaters. These seem to be extremely cost effective once you have committed to LPG. Are these just great or are there problems?

@rectangularBuildingNever come across them. Do you have a link for them?

@rectangularBuilding & @Limpopoboy I have issues with these inline water units, quite often its too hot and when you adjust down, it decides to kill the flame (after all, you said it was too hot) and then doesn't come on again until after you've shrunken down to half size and are shivering... I still recommend a donkey, doesn't require much fire, doesn't have a tank and you just add from the cold water to the mix to suit, if, of course, you are one of those that shower for an hour, the donkey's not an option, unless you have someone else standing by to keep on feeding it combustible material as needed... in Namibia we used to feed it Elephant dung at the one location, since that was plentiful.

In case you don't know what a donkey is, think large 1.2m, say 200mm pipe with copper coiled up in the length of this, so a chimney is still formed in the centre of the copper coil. feed water in the bottom of the coil and out the top to the hot water pipe... mount 200mm pipe over a burn chamber, to become the burn chambers chimney and voila, hot water, when needed as long as you have some combustible material floating about.

In Namibia they used the smaller 15kg? gas bottle for the burn chamber, top cut off and a large hole cut in the side, maybe 200mm by 300mm? and then the large long gas bottle to make the chimney/heating chamber + copper piping, of course... ok, not so easy as assuming the gas will light up and heat the water, but it works every time and should cost less to make and run than the gas option...

*EDIT ADD*

To clarify, I would recommend an evacuated glass tube HWC as primary with the donkey as backup, for those cloudy days... to use PV power to run a heating element is hugely wasteful and not financially the best move either, let the sun heat the water directly and have the donkey switchable behind the HWC or parallel to it, when you don't want the extra piping, because the HWC is providing warm enough water anyway.

Edited February 27, 20215 yr by Kalahari Meerkat
addition

3 hours ago, Kalahari Meerkat said:

@rectangularBuilding & @Limpopoboy I have issues with these inline water units, quite often its too hot and when you adjust down, it decides to kill the flame (after all, you said it was too hot) and then doesn't come on again

OK good to know. Without myself having any experience, Bosch claims that their heaters need especially low pressure to switch on (and presumably stay on) and provide stable temperature.

Example: Bosch WRD11B23 11 Litre Battery Ignition NG Gas Water Heater, https://www.sustainable.co.za/bosch-wrd11b23-11-litre-battery-ignition-ng-gas-water-heater.html

I was once very impressed with an electric Stiebel inline heater in a guesthouse. Stable temperature. I vaguely remember it might use 5 kW. Too high for solar but just an example of instant heating. Benefit obviously not needing a giant water tank.

Edit: Small Stiebel electric inline heaters seem to start at 11kW.

Edited February 27, 20215 yr by rectangularBuilding