Hayward H400 Heater Control Issues

[bobazonski]

Our pool was installed around 2007 and still has the original Hayward H400 heater. We had the original Jandy board recently replaced with the Zodiac iAqualink. The iAqualink system is great, and the heater does a good job at heating water, but the issue is the communication and/or relay between the two. The iAqualink temperature controls and on/off switch don't do anything at all. Regardless of whether the "heater" button on the iAqualink is on or off, the heater just stays on. This is an issue because the control panel on the heater is totally spent from years of sun exposure, so just to turn it on or off I have to mash the buttons for 15-30 minutes.

A few months ago, I had the technician who installed the iAqualink come back out, thinking he did something wrong, but to my surprise the relay worked exactly as intended. The heater toggled on and off with the push of the "Heater" button on the iAqualink, confirming that he wired the relay correctly. It stayed that way for a few months, but now the issue is back. I have no idea what the problem is or how to fix it. Does anyone have any thoughts? Could it be the control panel on the heater itself? Thanks, any help is appreciated.

 

[ajw22]

I suspect that the relay on your Aqualink board that controls the heater is stuck closed.

Do you have a multimeter? If so you can use the ohm or continuity function to check if the relay is opening and closing when you press the HEATER button on your Aqualink.

 

[bobazonski]

I can try that later, but just to confirm, the little red light does come on and I can hear the relay clicking when I press the button.

 

[ajw22]

I can try that later, but just to confirm, the little red light does come on and I can hear the relay clicking when I press the button.

The relay can click but the contacts can be welded shut and not op[ening to shut the heater off.

 

[bobazonski]

The relay can click but the contacts can be welded shut and not op[ening to shut the heater off.

I messed around with it a bit tonight and the switch seems to work consistently enough that I don't think it's a relay issue. With the pool running normally, I could get it to toggle "pool heat" consistently. The standby light on the heater stayed on because the pool was hotter than the set temperature, but the "pool" light on the heater toggled as expected, so I believe it was working as expected.

However, things were different when I set the equipment to spa mode. I was able to toggle the heater on using the "spa heat" setting, but on the heater the "pool" light turned on instead of the "spa" light. I manually switched the heater to spa mode using the heater control panel, but after that point the "heater" switch on the iAqualink stopped working altogether. The heater just remained on, regardless of what the iAqualink switch was set to. I had to use the heater panel to manually set it back to standby, and then turn the power off before the heater would respond to the switch again. Any thoughts?

 

[ajw22]

See page 17 in https://hayward-pool-assets.com/ass...ries-millivolt-owners-manual.pdf?fromCDN=true

Your heater is wired for Remote Thermostat mode or Remote Control mode. You need to look and see how it is setup. Does the heater show bO or LO when off?

The heater does not change between POOL mode or SPA mode when under Aqualink control. You should leave the heater in pool regardless of if heating the pool or spa. The Aqualink controls the heater the same way.

 

[bobazonski]

I have never seen the text "bo" appear on the panel so I decided to open it up and see if I could check whether the wiring/dipswitches were set correctly. My heater's board looks nothing like the images in that manual. Luckily I was able to find the original manual which has stayed with the house for all these years, turns out this is a "H400IDL2" model which doesn't have dipswitches. All I had to do was hold "mode" and "down" for three seconds (which luckily worked given the state of the buttons) and now it's in remote operation mode. As far as I can tell, it's working exactly as it should. I can't believe it was that simple! Thanks for all the tips and for pointing me in the right direction.

 

[ajw22]

Yeah, Hayward has different model heaters with similar model numbers which make it confusinging to know exactly what you have. Glad you figured it out.