JohnMarc

What is the KW rating of the heat pump you are using?

Apologies for the potentially dumb question but do I understand this correctly? Specs for 18.7kW ITS Inverter Pool Heat Pump tells me that it does 6.9 m3/h to 40 C....... my hot tub is 1500 L (or 1.5 m3) so does that mean I can heat up the hot tub in less than an hour? (or 21 mins being precise) Love it, in fact when we go 4x4ing we are the buggers who still have the paraffin storm lanterns...... yes of course we have gained a lot with technology but those were good days and I do try and hang on to a little bit of it when I can......... Love it, in fact when we go 4x4ing we are the buggers who still have the paraffin storm lanterns...... yes of course we have gained a lot with technology but those were good days and I do try and hang on to a little bit of it when I can.........

Yup have tried the wood burning hot tubs and as romantic as it appears and sounds I found (having recently rented one for a while) unstable as regards temperature control, not suitable for suburbia as it looked like the next pope was being elected with the amount of smoke...... or I had set up a crematorium in my backyard,,,,,,,

Thanks Scorp007 I have to operate each unit individually as they are to far apart from each other. I am ow thinking of using the 10 tube High Efficiency collector ( https://itssolar.co.za/products/solar-water-heating/ ) and treating the actual hot tub as the "geyser" then if additional heating is required, redirect the water through the Heat pump to boost the temperature....... I have in fact found an (rather beaten up) old jacussi and am going to run some experiments with different piping arrangements to see which works best........ I am still trying to find the best filtration system bearing in mind the constant temp of the water.....

Thanks ..... that comes back to my initial question, as to do I need the solar geyser (my thinking was to minimise the time it would take to heat the hot tub in as short a time possible ) or can I heat the hot tub quickly enough using a 7,5 KW heat pump? I am told the ideal temperature range is 37 to 40 C .......

What I have done is simply built a plywood enclosure with plenty of ventilation ...... I painted on a resin to seal the wood completely ....... I live in an area where even plastic rusts 😂 so although everything was IP65 i wasn't going to take any chances, two years in and all good.

Okay here goes ....... Please be advised I really don't know what I am doing (as I am sure will be shown in my attached drawings) but I am hoping to get advise back on the following: Can I run the solar heated water through the heat exchanger although it is not "in operation" or is it a sealed unit unless in operation, therefor necessitating the installation of a solenoid valve redirecting the flow when the heat exchanger is switched on? Does the level of the geyser affect the free flow of the water, I am trying to not use an electrical pump to drive the water through the system when the tub is not actually being used? Some feedback would really be appreciated..... Thanks

😂 maybe that is what is needed for me to actually get this design done.......😇

Thanks Bobster, you got me looking online and have found some good options...... one issue ticked off now to the rest of the list.......🙈 Merry Christmas to all by the way, I trust it was a good one

Yes I am actually doing the entire tub build due to the unusual sizes and shapes needed so plan to have very good insulation all around including the lids.....thanks

Hi Scorp007 Yes exactly my thoughts, but my complete ignorance about these systems even frighten me....... so could I run the water through the solar tubes all day and then at night depending on the temperature required turn on the heat pump to heat the water those few degrees more? The idea being that the ambient temp. of the water is significantly higher meaning that to heat the water to hot tub temperatures would be done a lot quicker.......my question is I guess would I design a water system that runs through the heat pump/exchanger which I only turn on when wanting to actually use the heat tub?

Thanks Frivan. In my ignorance I assumed that solar heated water (the evacuated tube type, if that is the right term) would have to be constantly circulated because of the pressure build up...... these would only be used when the tub is being used..... basically I am trying to take advantage of the sun but cannot see myself having 1500 litres (x3) worth of geysers to store the hot water...... Hence me thinking of some sort of system that keeps the water (slowly circulating) in a system through the tub, with a sealed lid, and then when they want to use the tub they would use the heat pump to get up to the desired temperature if its not already there. But even me writing this I am seeing errors in my proposals....... I am trying to find info about the best (quickest) way to heat a hot tub...... want to use a heat exchanger/pump (as I do have plenty of solar generated electricity...).. but at the same time I have a lot of sun throughout the year...so got me thinking of the water solar heating... trying to make the best of both worlds I guess........and how to combine them......

I have a guest house and I am installing 3 hot tubs for our guest units, my thoughts are the following: I want to use a heat pump/heat exchanger (7.5 KW) for each tub .... I would like to use a solar heater of some sorts to retain an ambient temperature in the system but limit the use of the heat exchangers only when the solar heater cannot provide the desired temperature, (say at night or on cloudy days....) .... I don't even know where to start. Can I for example have the solar system constantly circulating heated water in the hot tubs but when the temperature drops too low the heat exchanger kicks in to boost the temperature? If anybody can advise me where to start I would greatly appreciate it. John

Is the breaker there as a way to isolate the battery bank from the inverter? If we assume I go the breaker route then are the fuses still required

As this system takes shape there is still one question I haven't managed to get an answer on, that is on the battery side why is a fuse and a breaker necessary, surely just a dc breaker would have the same protection a fuse would offer

I haven't been very clear and should have laid out my expectations of the system that I am installing, Halfway there, the batteries are installed (48v 220 Ah) the Invertor is installed (connected to the batteries) BMV 702 is installed and all working well..I am in the process of sourcing solar panels and will install those later ... Now want to connect to the board..... I am looking for an interrupted power supply for when (not if) Eskom start playing their games again. All options are still on the table but when Eskom switch us off I simply want to have uninterrupted power. When the grid comes back on I am happy to use Eskom to charge the batteries and get ready for the next shut down..... Is this an issue I should be aware of....... are you saying that with the inverter disconnected I would not be charging my batteries Maybe you can help find a 3 phase changeover diagram so I can apply some of my own grey matter to the issue and have a better understanding of the points you raise

You'd be most welcome....thanks for everything

Yup very clear .... thanks for everything, one more problem, now how do I turn water into wine..... this shutdown is threatening my stocks......or is it not that type of shutdown that can be solved with a few switches.......

Aah yes got it thanks a lot

Hi Jaco if you go back a few posts of mine I said I did not want to run the 3 Ph hot water systems during a shutdown, as I mentioned they automatically switch over to gas with the use of solenoid valves, normally open but in a shutdown they redirect the water through the gas geysers automatically activating them. I don't have a particularly high usage house etc. so 5 KVA should be ample. I would like to avoid reinventing the wheel if possible and effectively switch from # Phase to a single phase supply.

Thanks so much Gerrie, really appreciate your concise response. Can you possibly elaborate on the neutral ..... there is no neutral feed to the water heaters...certainly not that I am aware of.... only three core cable connecting to heaters..... but a good point you raised, would the neutral from changeover switch connect to all three neutral bars, effectively bridging them, would this not have an impact on the earth leakages on the individual phases under normal operation?

Okay so I am thinking the best way would be to give a clearer picture of what I am actually dealing with..... I am really hoping the attached picture is self explanatory ......

Does anyone out there have a wiring diagram showing the operation of a changeover switch from 3 phase to single phase, battling to find one on the net. Well battling to find one that makes sense to me.......

Yes the geysers are fed directly from the DB.....

I am actually liking the idea of the changeover switch that turns the three phase into a single phase...... I had no idea this was possible, please elaborate..... If I can find a way to automatically switch off the feed to the three phase geysers everything else in fact is on single phase. So a far simpler solution is possibly the 3 Phase changeover switch scenario assuming I am able to switch the instant hot water systems off. Am i right I would simply do that with a three phase contactor ..... but then what would happen when the power comes back on....is there a delay in the switchover process back to three phase. Hell I hope I have made sense here......please forgive my ignorance .....