Problems with wiring for Heater Fireman's Switch

Jump to latest Follow Reply
S

sjsoldo

0
Jul 17, 2009
105
Pentair Minimax 250 heater with pump controlled by an external timer. I am trying to figure how to turn off the heater using an external switch to power down the heater 20 mins before the pump shuts off. My problem is that I am looking for a circuit in the heater that could serve this purpose.

The "professional" that installed the heater used the wiring to the thermal fuse as the circuit to turn off the heater. So when the timer shuts off, the heater "thinks" the thermal fuse is blown and shuts off the gas. Problem is that this triggers one of the safety mechanisms of the heater; it WILL NOT restart the next cycle, displays "ERR" and "call technician". I have to switch the unit off then on again to reset the system. It works fine until this happens again.

So I call Pentair and they instruct me to use the "Common" and "Pool" terminals on the circuit-board for this purpose. But there was no jumper between these two terminals. When I connect them with alligator clips, it makes no difference how the heater functions, including the fatal error described above.

Any ideas where to wire this properly?
 
So what is the controller that you have the unit attached to? Also, do you have the heater on all the time or only when you want it to be on?

The Pentair folks assumed you had automation such as an Easytouch.
 
Pump and heater are connected to a digital Intermatic timer. Heater is "on" all the time but of course is controlled by its thermostat.

I made it clear to Pentair tech support that I was using an external timer. On doing more reading, there is a jumper on the circuit board the needs to be removed to use an external switch.

Instead I was thinking about using the circuit for the pressure switch for this purpose (I.e. external switching).
 
What timer model are you using? Does it have an option to turn something off 20 minutes before it shuts off the pump or a heater cool down option? Cutting into any of the safety circuits like the pressure switch isn't the correct way to deal with your issue. Even using the thermal switch option done by the "professional" was not a correct way either. Yes the external switch option on the heater is the way to go but again, the timer has to have the option to turn if off before the pool pump shuts down.

I'm guessing you have a minimax plus heater?
 
I am using a popular digital Intermatic model and it does have two dedicated terminals for a fireman's switch. You can program it to shut off up to 20 mins before the pump goes off.

I have the Minimax NT with the digital control board.

I am going to call Pentair tomorrow as there is a proper way to do this. I think it involves switching the "com" (for common") and the "pool" terminals on the circuit board. But there is a jumper somewhere on the board you have to remove.

Both the Pentair installation and service manuals do not explain this in any detail. I guess they wanted it to be a proprietary secret.
 
Was the heater in remote mode when you tried what Pentair told you?

I would be interested in a "proprietary secret" that they have. I've worked on these units since they showed up on the market but I've never had a need for using a fireman's switch nor have I seen any that other companies have installed used one. You learn something new every day so I will be waiting to learn.
 
Hi,
I know it's been a couple years since you posted this, but did you ever figure out the wiring issue. I am having the same problem. I just installed an older heater, a pentair minimax nt 300 dv. It's electronic igntion, and the circuit board et al. My timer is an intermatic with a fireman's switch, and according to what I read, you can run the heater through the timer to shut it off, say, 20 minutes before pump shuts down. I see the switch in the timer, and the two wires coming from it ( i am guessing it's non-polarity as it's not powered and is just an open/close switch. But my question is where in the heater do you connect it to? According to the wiring diagram, there is a jumper that you would remove and I am guessing you would wire it out to the switch in the timer box....i.e cut the wire and connect both cut-offs to the 2 wires coming from the fireman switch to complete the circuit...in theory, the switch would engage and open the circuit that the jumper was originally closing, making the heater power down. When not engaged, the heater would work as if the jumper were there... My fear is just wiring to the wrong thing and frying the board. lol. i was tempted to trial and error it but don't wanna shell out, say, 700 bucks for a new board. I am almost sure the jumper shown in diagram is the one you would utilize (labeled external switch) but want to be absolutely sure. Anyway, if you get this, any help would be appreciated. I know it's been a while, but you're about the only topic I googled that came close to my problem. Thanks.
 
cberr said:
Hi,
I know it's been a couple years since you posted this, but did you ever figure out the wiring issue. I am having the same problem. I just installed an older heater, a pentair minimax nt 300 dv. It's electronic igntion, and the circuit board et al. My timer is an intermatic with a fireman's switch, and according to what I read, you can run the heater through the timer to shut it off, say, 20 minutes before pump shuts down. I see the switch in the timer, and the two wires coming from it ( i am guessing it's non-polarity as it's not powered and is just an open/close switch. But my question is where in the heater do you connect it to? According to the wiring diagram, there is a jumper that you would remove and I am guessing you would wire it out to the switch in the timer box....i.e cut the wire and connect both cut-offs to the 2 wires coming from the fireman switch to complete the circuit...in theory, the switch would engage and open the circuit that the jumper was originally closing, making the heater power down. When not engaged, the heater would work as if the jumper were there... My fear is just wiring to the wrong thing and frying the board. lol. i was tempted to trial and error it but don't wanna shell out, say, 700 bucks for a new board. I am almost sure the jumper shown in diagram is the one you would utilize (labeled external switch) but want to be absolutely sure. Anyway, if you get this, any help would be appreciated. I know it's been a while, but you're about the only topic I googled that came close to my problem. Thanks.
Click to expand...

all you have to do is set the front panel mode to remote. Then the terminals marked common and pool or spa will respond to contact closure. Wire the fire mans switch to these 2 terminals and when they open 20 minutes before filter turns off heater will shut down with no error codes. Hope this helps all of you.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply