heater bypass lessons learned


Jun 5, 2017
Las Vegas
I installed a heater bypass diverter, actuator, and check valve. This was mostly done to preserve the core. Last time I serviced it, the header where the tubes are soldered in, were pretty eroded. I expect it to die one day, I will probably be away for work. If I do end up replacing it, I want it to out of the regular flow unless needed. For me it was worth the $100 for a intermatic actuator, $50 check valve, $50 diverter, and electrical/plumbing consumables.
Plumbing installation was easy. I figured I dont need to explain that.
The electrical took a little more time.
I have a Jandy Iaqualink. All my JVA outlets are full. I was not going to spend $80 or more on a relay board, but you can. It makes it easier. This is what I ended up wiring for all the other extra JVAs I installed; swim jet, main drain selector. This set up requires a 24v DC, not AC relay. The JVA outlets are AC, the 2 pin Aux lines are DC. I just used a din rail.
The tricky part with the heater bypass is the the Aux pins in the Iaqualink for the heater (e-htr), cycles once at temp. So you turn on the SPA, the actuator starts turning, once decent flow (pressure) is seen the burner ignites. Once the heater gets to temp, the Iaqualink turns off the heater, the actuator starting turning away from the HTR, until there is demand again. I didnt want the heater getting stuck with no cool down or large temp changes in it.
I ended up finding this handy time relay. I put it between the aux input of the relay, it gets trickier because it needs constant power to stay energized. With the timer set to delay on break (Dr on the relay), the heater AUX is energized, the time relay closes and the actuator turns. Now once at temp, the time delay starts counting when the heater is turned off. I set it to 20 min or something. The heater is allowed to cool down, then it is bypassed.
Ill sketch up how I wired the timer, but if you are doing a project like this you should be able to figure it out yourself.
Like I said this is more a lessons learned than a how to. But so far its working very reliably.