Heater shuts off in spa mode

[schoolpoolboy]

I have 30k in ground w/spa. Having trouble with Pentair minimax plus 400.
With heater in spa mode and valves in pool mode, Heater fires up and runs fine. But if i put valves in spa mode? Heater shuts down after a couple minutes. Move valves back to pool? and it fires back up.
I have thoroughly cleaned heater and filter/baskets, no obstructions. Both hi&lo limit test ok for resistance. Pressure witch did not. Does this mean pressure switch is bad?

 

[jblizzle]

Well, there is no way for the heater to know the valve positions ... the only thing it can detect is the flow and temperature. So, either in Spa mode the water temp is already high or there is not enough flow. Do you see adequate flow in the spa?

 

[schoolpoolboy]

Ive always believed that luck is the result of hard work and homework coming together. Well....Luck happened today.
On a hunch, it was something I considered early on but it was never suggested in the month of research prior to today?

But today I go to start heater expecting it to do same thing it did last night, IE: Shut down in spa mode? BUT Today?... Nothing? No led's (except power) No ignition? Nothing!.

So on a hunch, I thought that maybe the SPA thermostat control knob itself might be faulty? So seeing as how the pool side controller appeared to be working fine? and I dont ever plan on using heater to heat pool? Why not use pool thermo control as spa control?

So i crossed wires on front panel rocker switch to circuit board. and.....WOALAH! IT WORKED! An hour later I was enjoying an ice cold Corona in my 105 degree spa. And it stayed that way until I shut it off for the night.

I know I know, It's hardly a conventional recommendation or solution, and surely NOT something Pentair and its army of techies would subscribe to.

Not only that, Its a bit premature as well as presumptuous on my part to assume "problem solved" right? The real test will be tomorrow, and the days that follow. Lets see if she works 2 days in a row? then 3? and 4?

Pool Gods willing? I won't be opening the panels (20 times in 4 weeks is plenty) on my minimax till next year.

THANK GOD and Thank You everyone at TFP for all you do. I hope this helps someone in the future?

 

[jblizzle]

My heater has 2 knobs as well, but really no need for them. Why would I need to set 2 temps and use a switch to select when I could just as easily turn a single knob. I think I have read here about a similar solution. Nice work!

 

[ps0303]

As these units get older I find one common problem, the rocker switch. You really only need one side of the rocker switch and one thermostat to work in order to have hot water.

 

[Pool Clown]

Why would I need to set 2 temps and use a switch to select when I could just as easily turn a single knob.

Two reasons:
1) Heater manufacturers bowing to lazy customers requests.

2) Some of the older automation systems that did not have an on board temp sensor/ thermostat would offer two different switch leads for heater control, one for pool and one for spa. Those would merely just close a switch and allow operation of the heater to it's pre-determined set point, pool or spa. the automation's connection to the heater would replace the heater's switch

 

[jblizzle]

Well at least one of the reasons is valid :lol:

 

[Pool Clown]

Well at least one of the reasons is valid :lol:

Well, it is probably because heater manufacturers never wanted to put definite temperature marks on the control knob. It was always a color graduation or marks, therefore there was no way to definitively set the heater to say 80 degrees without repeated trips to the heater to make small adjustments to eventually "find" the 80 degree point on the dial.

Putting degree marks would have forced the manufacturer to have a higher level of accuracy on the thermostat (Higher quality= Higher cost) not to mention the liability.

 

[Richard320]

Mine does it too. But since I control the flow via the valves, the heater really doesn't know whether it's heating the pool or the spa, and running it using the pool control works perfect. I suspect there is some alternate plumbing arrangement somewhere that wasn't utilized in my installation.

 

[maxmouse]

pentair 400 n/g unit will not reach set point on spa set at 104, tried using pool setting also no luck. thanks Doug