Pool heater/pump question

[wayner]

My pool has a Jandy Lite 2 pool heater from 2006 that looks like this:

This heater also works as the control for the pump, including a simple timer that allows for one off time and one on time per day. The heater also has the smarts to keep the pump running for five minutes after the heater shuts off so that the burner cools down - and it shuts the heater off five minutes before the daily off time.

The heater isn't working and the repair guy suggested that it needs to be replaced as there is a lot of rust and he said "most of the refractory material has disintegrated and collapsed onto the burner tray. Due to the high cost of the refractory kit it is not advisable to repair this unit". He doesn't sell heaters so he has nothing to gain from telling me to get a new one - in fact he would make more money if I told him to repair it.

It is my understanding that not all heaters have the electronics to control a pump. Any suggestions on what to get to replace my heater?

My pool shop has suggested a Raypak heater, but I don't know that they control the pump. Ideally I would like a heater that can be controlled by a smartphone app or other Home Automation system, but I don't want to pay more than $200 for such functionality. (As an aside why does it cost so much to put "smart" functionality into a pool system when the hardware is not dissimlar from a Raspberry Pi Zero that is worth about $25 (including peripherals).

Note that I have a solar heating system so I like to run the pump from sunrise to sunset. I live in Toronto and the pool is open from early May to early October but I don't heat it during the beginning and end of the year unless the weather is good. During the summer I like to keep the pool at about 84F with the solar and gas heaters. I have a Control4 Home Automation system so I could use that to trigger a relay to turn the pump on and off.

edit - I forgot to clearly state that I have a NatGas heater and that is what I would like to buy again. My pool is about 100,000 L so I think I need a heater that is at least 250,000 BTU. Is it worth getting a larger heater? What are the advantages of that? Just faster heat up times?

 

[CJadamec]

For a natural gas heater the most widely recommended brand is the Raypac units. They are a simple proven design without a lot of extra parts.

As for size go as big as the gas line to your equipment pad can support. The difference in cost between a 100k unit and a 400k unit is minimal. With gas heaters the faster you can heat the pool the cheaper it will be to run the heater in the long run because the heater runs less and the pool has less time to loose heat while you are trying to heat it.

To get the functionality you are looking for in terms of a smart phone controlled system it's either going to mean you need to design and build a Pi system yourself or shell out the money for a premade system. Historically pool automation has been expensive because the market supports the high prices and there has been little to no competition to drive prices down. Every major manufacturer uses a proprietary hardware and software in their control systems so aftermarket systems are costly to develop.

In the last year or two the influx of VS pumps has driven the demand for a different breed of control system for a much larger portion of the pool owning public. The iQPUMP01 system from jandy is the first mainstream example of this newer type of control package. Its not a perfect fit for you but its not too far off.

iQPUMP01 | Jandy

The Jandy Variable-Speed Pump with App Control allows pool professionals to easily install, set up, and control Jandy variable-speed pumps using a smartphone and the iAquaLink app.

www.jandy.com

 

[wayner]

Thanks for the reply. I don't mind doing a bit of hacking myself and I have several RPis that I play around with - I have one that is connected to the pipes going to and from my solar heating panels that has DS18B20 temperature sensors to measure the temperature before and after the solar heating panels so that I can monitor this. If I do my own system can I interface with the Raypak system using something like an RS-232 interface, or do I have to use the RPi to read temperatures, flip relays, etc?

I am not sure if my pump is VS, but I need to keep the pump running with a fair bit of force to push the water up to my roof to flow through the solar panels. So I am less concerned about controlling pump speeds.

 

[CJadamec]

VS pumps simply make controlling the pump cheaper and easier because there are no high current line voltage relays to worry about.

Your gas heater isn't going to have rs-232. Gas heaters are simple on/off devices. Some will have an external remote input that is either control voltage or line voltage or dry contact/jumpers. Best to read up on the models you are considering to figure out which one will best suit your automation requirements.

If you've already got a DIY solar controller set up then you should have no problems building out the rest of the system as it's all mostly just basic relay controls. You may look into salvaging the line voltage contacts your broken heater was using as a pump controller that is a good place to start looking for some bits to save you money.

How is your SWG being controlled? Does it have its own timer or was it too being controlled from the heater.

 

[wayner]

My SWCG is a Jandy Aquapure 1400. It simply has a percentage adjustment. It is controlled via buttons on the SWCG controller. It is able to sense flow, temperature and salinity levels but it seems like this can't be integrated into an automation system, from what I believe even stuff like the Jandy Aqualink can't control the SWCG. This whole automation issue is so frustrating to me as it could be done so easily with just a little bit of smarts in the heater, SWCG, etc, and some sort of basic interface that has been around since the 1970s and should only cost a few dollars. It could all be controlled by a RPi Zero W which costs about $20 (if that) including power supply, case and uSD card.

Looking at Raypak it likes like the suitable devices for me would be a P-R266A (266,000 BTUH), P-R336A (332,500 BTUH) or P-R406A (399,000 BTUH).

Apparently there are models with pilots and electronic ignition. What are the advantages of electronic ignition? To be honest, I thought this was a disadvantage with the Jandy as I had to replace the hot surface igniter several times and it cost over $100 each time.

Regarding Control Options the Raypak website says:

The digital system (pictured) requires external power (120VAC or 240VAC) and generates a pilot only when there is a call for heat. It provides simple setup and easy programming, as well as easy-to-understand diagnostics and simple connections to remote controls. The millivolt ignition system does not require external power. It generates its' own current internally, with a small thermocouple driven by the constant pilot.

How do you connect the pump to a timer and ensure that the pump runs for a few minutes after the heater shuts off so that you don't get superheated water in the heater?

It looks like there is a 2-wire remote control. I could use this to achieve automation with my Control4 system via a relay. I am guessing that I might need two relays - one to control the heater and one to control the pool pump.

But it would be great to also get a temperature reading. This sounds stupid but the easiest way to get a reading might be to put a camera aimed on the LCD screen of the heater. You could then read it by OCRing that feed.

I guess the other way to do this would be to connect a temperature sensor (like a DS18B20) to a RPi. But where would I put the sensor? I am not keen on drilling into the piping to put the sensor in that spot. Would I run it on the pool deck into the pool itself?