Pool pump configuration with heater - Page 1
Forum section: electronics / general

author: Sjp770
author_rank: Newbie
timestamp: February 14, 2025, 11:20:53 pm
content: After watching Dave's vid on eevblog2 channel I thought it might be a good idea to ask some questions here from more technical users. I have the same set of questions on Reddit, but keen to see this communities take on it.Single vs dual pump for heat pumpsI see a lot of single pump setups with heat pumps, using bypass valves to get the heat pump flow just right. How does this compare to a separate heat pump circuit?There are a few items to consider:- 2x pumps is more capital expenditure and more electrical cost.- Single pump systems may over chlorinate when the heater needs to run more than the chlorinator- Variable speed pumps - how well do they work when you set a bypass for a certain speed?- Can a sufficiently advanced clorinator automatically turn off electrolysis based on an ORP probe reading to stop over chlorinating due to a pool cover or running too long due to the heaters hours?During the design phase of the pool I want to make smart decisions based around running costs. I feel like the two pump system is designed to deal with less advanced or reactive chlorinators and back in the day two single speed pumps weren't that expensive to run./End dump from Reddit.So I feel like in this day / age etc we should be able to have control systems to save electricity. If a chlorinator is just an electroysis unit for splitting sodium from sodium chloride or magnesium from magnesium chloride, surely if an ORP probe can read something that allows the controller to understand how much chlorine is in the system and shut it off. Same as design the electrical circuit that the chlorinator can only run when the pump is powered. As I understand it the current way Todo this is a gpo on the chlorinator. How the heater then runs the pump relies on you buying the same branded components.For any smart home people, I'm considering controlling the run times of equipment via home assistant. If I setup the GPO for the cholinator to be powered through a contactor that also requires the GPO for the pump to be on, either by physical wiring or logic rules in HA then I'll never run the clorinator without the pump being on. I can do the same with the heater, so when the schedule for the chlorinator ends but the heater is on the pump must stay on. If I do this with a relay board controlling contactors between the breaker and the GPO for each item or the directly wired heat pump it seems to me that I could choose a far cheaper chlorinator? Just test and adjust the schedules manually, or even look at an ORP probe that can read into home assistant, and if all it does it block the chlorinator running then I shouldn't have the issues at all?Thinking more on this I would choose let's say a 24vdc contactor.Main sub board would contain the following:20A RCD-> 20A contactor -> Heat pump10A RCD-> 10A contactor -> Chlorinator10A RCD-> 10A contactor -> PumpLogic board would have 24vdc going into NC terminals of three relays.Output on relay #1- to Chlorinator contactor and to input of Pump relay trigger with inline diode.Output on relay #2- to Heat pump contactor and to input of Pump relay trigger with inline diode.Output on relay #3- to pump with diode inline .So anytime the chlorinator or heat pump are scheduled to run the pump must run. But I can also run the pump only for backwashing or manual pool cleaning. I'd also pop some local over ride switches with indicator lights at the pump.This way I'm still relying on the inbuilt controllers on the chlorinator and heat pump, but not their timers, which can't trigger the other items. Also means I get "wifi control" without paying for the top model.

author: BradC
author_rank: Super Contributor
timestamp: February 15, 2025, 04:33:27 am
content: Quote from: Sjp770 on February 14, 2025, 11:20:53 pmThe only comment I'll make is in Australia we tend to need a decent whack of stabiliser (20-80ppm) to keep chlorine in the pool with the UV exposure we get. Anecdotal evidence (read elsewhere, not mine) is that any stabiliser level above about 10ppm seems to screw with ORP readings.Just something to consider if you are really looking into ORP.

author: Poroit
author_rank: Frequent Contributor
timestamp: February 15, 2025, 05:21:40 am
content: G'day Sjp770,I have a 30 year old, 55,000 litre outdoor pool which was fitted a Heat Pump about 3 years ago.Single speed Davey Pump, Bypass Valves and a very basic chlorinator.How big is the pool you are planning and how many hours of direct sunlight will it get?

author: Whales
author_rank: Super Contributor
timestamp: February 15, 2025, 05:54:01 am
content: QuoteWhich vid is this sorry? I'd like to have a lookQuoteIs there an advantage to not sending all the water through the heatpump? I thought those valves were just for when the heatpump leaks and you want to take them out of service.My vague understand of refrigeration efficiency is that you want a maximum of medium (water in this case) moving through the unit. But I have only read about residential aircon, not sure about pool heatpumps.QuoteMany pool heating products have a set of terminals you can attach an ordinary (low-voltage) relay to to turn them on and off. Would be worth checking yours before spending money on a big contactor. Also this might let some of them do graceful shutdown cycles (?) as they stay powered afterwards.QuoteSome chlorinators have different power levels you can run them at.Safety concern: make sure your chlorinator can't run when no water is flowing. It can make hydrogen and oxygen gas (explosive).Consider what happens if one of your smart relay powerpoints/powerboards fails or loses wifi, then only the chlorinator gets turned on (not the pump).

author: Sjp770
author_rank: Newbie
timestamp: February 15, 2025, 10:38:41 pm
content: https://youtu.be/tA2qm1-BVCY?si=Z9U6XWlhbNG8EfqOMy plan is to buy appropriate sized equipment for my pool (39,000L) but not spend the extra on new fancy features that require their own apps. I run home automation so very keen to have direct control. If the equipment powers up then gets to work based in its settings I can avoid using the built in timers and use my automation system for all scheduling and remote overrides. This means full recording of activity and access anywhere in the world. If I'm away and forgot to turn off the heater I'll be able to flick a switch on my phone and it won't run while I'm away. Side note, I'll probably also try and find a good way to get pH and temperature of the pool into the same app. I'm not sure how useful ORP will be to me as I haven't researched it yet.I'll be getting a minimum of 3x Finder 22.32.0.024.4520 24v or 12v contactors (NC 25A). They will sit between the rcd's and the load, installed by the sparky. I'll trigger those with a Brainboxes ED-588 MODBUS Digital I/O boxhttps://au.element14.com/brainboxes/ed-588/ethernet-digital-i-o-device-8/dp/2357912mainly because it has a high operating temp and will be robust. I've used their 24vdc 5 port ethernet switch for years already.The chlorinator digital out will trigger both the chlorinator and the pump (with diode on the pump leg)The heat pump digital out will trigger both the heat pump and the pump (with diode on the pump leg)The pump digital out will only sen to the pump (with diode)As these are electrical connections hardwired and not some logic I can get wrong, they will never allow the pump to not run. I'll also add latching IP rated illuminated switches on the ourside of the control box so I can override the auto program. And if I move out I can take the control gear and just flick the contactors over to ON.I'll also have a DMX module in my control box to add the RGB light control to my home automation instead of relying on the light manufacturers options. The rest of my house is controlled by DMX so it will be easy to integrate.

author: Whales
author_rank: Super Contributor
timestamp: February 15, 2025, 11:51:52 pm
content: From the video comments, regarding why higher flow rates of water make the efficiency lower:QuoteHuh, interesting. It ruins the pressure dynamics of the refrigerant loop. I assume this means it doesn't have a TXV but instead a fixed orifice? Or maybe even with that there is not enough flexibility.Also a COP of 16 is insane when compared to residential aircon (typically COP 3-5). That would potentially make plumbed water heating in house more efficient than ducted air conditioning, unless I'm missing something important here.

author: Whales
author_rank: Super Contributor
timestamp: February 16, 2025, 12:19:15 am
content: Quote from: Sjp770 on February 15, 2025, 10:38:41 pmAny thoughts on cheaper stuff, likehttps://nixon-dce.com/search?type=product&type=product&q=contactor?QuoteGood, thankyouAlso make sure the chlorinator also has a proper flow switch or similar so it has a fallback if the pump stalls or relays fail.QuoteBonus points if your poolpump can be controlled over DMX-512. Dimming xD

author: Sjp770
author_rank: Newbie
timestamp: February 16, 2025, 02:04:55 am
content: The nixon gear looks ok, but I really need the ON-AUTO-OFF switch to bypass the automation without taking it out of the board.I'd consider a cheaper option for triggering the relays, but I like the industrial build quality. Means I dont have to worry about ventilation in the control enclosure.Another option for tracking the pool stats is here:https://atlas-scientific.com/kits/wi-fi-pool-kit/Expensive but i'll consider it above the aliexpress options.

author: themadhippy
author_rank: Super Contributor
timestamp: February 16, 2025, 02:12:04 am
content: Quotenext step dancing fountains

author: Sjp770
author_rank: Newbie
timestamp: February 16, 2025, 02:20:38 am
content: I was going to look to control the pumps speed too later, seeming it's a variable speed rs485 2Hp pump I'll definitely investigate. Hadn't thought about a DMX to pump translator Arduino solution though. Cool idea!

author: Poroit
author_rank: Frequent Contributor
timestamp: February 16, 2025, 06:06:52 am
content: Based on your pH & ORP readings, are you going to dose Acid and Chlorine into the pool?

author: Sjp770
author_rank: Newbie
timestamp: February 16, 2025, 06:21:43 am
content: Acid maybe. I'd like to track the pH and ORP, but the doser is $1400. If I have that atlas gear I can set it up to dose. The downside of it not working is I have to manually dose so that's not too bad. I'll only set hours per day of the chlorinator and let it take car of itself once on. And as I'll be charting the ORP I should be able to adjust the schedule as needs.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: February 16, 2025, 11:04:17 pm
content: Quote from: Whales on February 15, 2025, 11:51:52 pmTemperature differential, system losses and system scale.A pool heat pump is very powerful, it gets its efficiency from doing a lot of work relative to the system overhead. By contrast a hot water service is a very small unit. Hot water is 60C vs 20C ambient while the pool is 25C and ambient is about the same (high temperature differential hurts efficiency). Pool heat pump losses are low because you're doing it all in the one unit instead of running a refrigerant circuit several metres away as with aircon. The losses in the PVC pool piping are out of scope for the calculation, which makes the picture look even sweeter.

author: Poroit
author_rank: Frequent Contributor
timestamp: February 17, 2025, 07:07:57 am
content: Suggestion....If you have not had a pool before, get it installed with basic equipment, no pH or ORP sensor but leave provision in the plumbing to add bits and pieces later on.Get used to maintaining the pool and visits to the local pool shop for water tests and chemicals. Mine and others I know have around three visits per swimming season.Go for a pool with a light Blue finish, that way you get a better feel for how the water looks.( You get a feel for it after a while)