Pentair Minimax 400 CH issue

volkg35

Member
Aug 3, 2010
20
Hi all I just bought a house with an inground pool and this heater setup. The heater worked fine last month and I recently noticed that the water was not consistently coming out hot and the pool was not reaching the set temperature. Further investigation revealed that my heater would run normally with all front panel LED's lit properly (service light was not lit) for about 5-10 minutes, then the heater would turn off, leaving the "Heat" LED unlit, and the "Service" LED lit. After about 5 minutes the heater would turn back on and run normally again and continue this cycle. I opened up the front access panel and looked at the burners. The pilot looks good and all of the burners are burning blue without any apparent issues. Also, the top vent is unobstructed. Any ideas as to what the heck is going on with this?
 

waste

TFP Expert
LifeTime Supporter
Mar 29, 2007
4,160
Coastalish 'down easter'
Welcome to TFP!!

Sounds like the 'hi limit' switch is tripping. (For more info on bypassing it to test, you have to prove that you'll not abuse the info in a dangerous way :) :hammer: )

Seriously, we can help you figure this out BUT - we need to know that you'll be responsible and follow our advice to the letter!

The safety switches are there for a reason and you SHOULD NOT!!! run the heater without them functioning for any extended period of time :rant:
 

Pool Clown

In The Industry
Sep 5, 2008
1,882
Silicon Valley, CA
If indeed it is the hi limit opening, the fact that it starts again proves that the hi limit is probably ok. Chances are the hi limit opening is a symptom and not the cause of the heaters problem. I would start with the by-pass that mixes the water in the heater. If it doesn't open correctly, the water temp rises to much on the second pass thru the collector, and the hi limit opens.
 

volkg35

Member
Aug 3, 2010
20
Ted - Thanks for the welcome and reply! The last thing I want to do is misuse information and cause harm to myself, my family, and lastly damage my equipment...after all, I just spent a ton of money on this house/pool/spa, hehehe. From my limited knowledge of how this whole system works, I came to the conclusion that it was one of the safety switches or the thermal cutoff fuse...but realized it couldn't be the fuse because the heater would not fire up at all if it was blown, correct? If indeed it happens to be one of the switches are faulty, I will buy a replacement no problem (its gotta be cheaper than hiring a pool company to do it). In any event, I pulled apart the front access panel and opened the front control panel and did not see where the thermal fuse/safety switches are. So in following your advice to the letter, what do I do now?
Pool clown - where is the bypass located and how do I test it?
 

waste

TFP Expert
LifeTime Supporter
Mar 29, 2007
4,160
Coastalish 'down easter'
I will defer to the clown on this one :p I know he's right :goodjob: I don't know your unit very well, (ask me about a Max-E-Therm and I'll be right there :mrgreen: ) Pool Clown, has shown his knowledge and expertise here and I'd follow his advice :cheers:

(however, on the Max-E-Therms, it only takes a couple minutes for the 'thermal regulator' to show that it's shot :? )
 

volkg35

Member
Aug 3, 2010
20
Bump - any ideas where the bypass is and how to test? I'd rather have an idea before I start taking apart the unit, thanks!
 

Pool Clown

In The Industry
Sep 5, 2008
1,882
Silicon Valley, CA
Heckpools said:
http://www.poolcenter.com/parts_heaters_pentair_minimax_ch_pg1.htm

should be #19 in the partrs diagram
Correct, Take the cap off (#26) to access #19 and inspect for corrosion on the temp bulb. Put in a bucket of hot water, and see if the spool slides. Look closely, as it doesn't move very far.

Sorry it has taken so long to respond, hopefully you have corrected by now.
 

volkg35

Member
Aug 3, 2010
20
Thanks! I had a pool company come to take a look at the unit, the guy took one look at it and said that the unit is too old to be serviced, parts are hard to find, and usually on this model when one thing goes, others shortly follow and that I should just buy a brand new heater =( *sigh...and I have a big family party coming up and it will surely stink if my pool is too frigid to swim in.
 

Pool Clown

In The Industry
Sep 5, 2008
1,882
Silicon Valley, CA
volkg35 said:
Thanks! I had a pool company come to take a look at the unit, the guy took one look at it and said that the unit is too old to be serviced, parts are hard to find, and usually on this model when one thing goes, others shortly follow and that I should just buy a brand new heater =( *sigh...and I have a big family party coming up and it will surely stink if my pool is too frigid to swim in.
HORSE APPLES!!!
Although that heater has been around for a while, you can still get most parts for it. Just look at the link that was posted here for you by Heck to look at. All those parts, for the exception for the front door, you can still get. Unless your heater has quite a bit of rust, it sounds like the pool guy didn't want to, or didn't know how to diagnose the heater.
 

anonapersona

TFP Expert
LifeTime Supporter
Nov 5, 2008
2,598
Or, he got paid for this service call without fixing it and figured he'd get paid a lot more to install a new system.
 
G

Guest

I agree with the clown (that's kind of cool to say!).

I'll be happy to look for parts for you since I hate hearing this kind of stuff. Let me know if I can help.
 

volkg35

Member
Aug 3, 2010
20
Thanks all...I actually took a closer look at my heater... its a Triton Minimax plus 400 (made by Pentair about 9-10 years ago)...I realized the CH model is the millivolt model and mine is the IID model. I called Pentair for tech support and the tech also said that they no longer manufacture parts for my particular heater. I was confused because the schematics and owners manual pictures look exactly like the heater I have...unless I am wrong about this?
The pool heater itself is in pretty good condition, no obvious rust or debris blocking anything. The pool company did say that the service man wasn't familiar with Pentair products (nice to find out after the service call was made)...
On another note...so I go outside to see if maybe I can clean off the heat exchanger/burners/pilot light, lo-and-behold, my heater no longer ignites and all I hear is clicking (this is prior to attempting to clean)...gas valve is open (tried both positions) still nothing. Looks like the service guy did something to render the unit completely useless, now I have absolutely no heat at all whereas before I had intermittent heat. To top that off, there were cigarette butts in the heater area! What to do? Its T-minus 8 days before my housewarming party where my pool is the main attraction and my pool is going to be frigid! Anyone know of where to get pool heaters at a good price and have it shipped quickly?
Looks like I have learned an expensive lesson in the first month of owning a pool =(
 

volkg35

Member
Aug 3, 2010
20
**UPDATE** so I had another pool guy come out to check on the situation...looks like the old pilot light wire was mysteriously cut clean, and thats why the heater was no longer firing up. Pool guy replaced the pilot light, and actually took the time to properly diagnose the problem and found out that the Hi pressure limit switch went. He replaced that, now my heater works perfectly. Thank goodness I found this guy two days before my party, and everyone had a great time in my heated pool well into the night! On top of that, this guy gave me tons of advice and showed me how my system works...finally a pool guy who takes care of his customers and doesn't make me feel like I'm getting ripped off!
 

bstrudg

Member
Sep 4, 2010
5
What area are you in. I am in Orlando and need help with mine. Could you possibly give me the number of the guy who fixed your heater? I could use someone I could trust! Bill
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,897
San Dimas, CA (LA County)
volkg35 said:
**UPDATE** so I had another pool guy come out to check on the situation...looks like the old pilot light wire was mysteriously cut clean, and thats why the heater was no longer firing up. Pool guy replaced the pilot light, and actually took the time to properly diagnose the problem and found out that the Hi pressure limit switch went. He replaced that, now my heater works perfectly. Thank goodness I found this guy two days before my party, and everyone had a great time in my heated pool well into the night! On top of that, this guy gave me tons of advice and showed me how my system works...finally a pool guy who takes care of his customers and doesn't make me feel like I'm getting ripped off!
Google the business and see if it doesn't come up on Yelp and a bunch of other review sites. Then post just what you posted here. A guy like that deserves every boost you can give him. Maybe he'll get so busy he has to hire and train some help, which will ensure there's someone decent when this guy retires.
 

volkg35

Member
Aug 3, 2010
20
Re: Pentair Minimax 400 IID issue

Soooooo here I go again...this season, my heater worked perfectly fine after the pool was opened. The second time I tried to heat up the pool, I noticed the heater was not firing up, *sigh. Only this time, on the control panel, the power light is the only light that is on. None of the other lights (aux, pressure, temp, heat) are lit, and they usually light up green. The red service light is not even lit. I tried turning the heater on via the remote control panel inside my house, and the service panel outside as well, no luck. As for my super knowledgeable and friendly pool guy, I did refer a lot of people his way, and now he's missing in action ( I suspect the pool company he worked for overworked him and he quit without notice, every time I spoke to him he had a million jobs going on at the same time). Maybe all those referrals was a bad thing. Anyone have any ideas of what might be the issue? My feeling is that the control module might be shot, but I'm not an expert on these things and don't want to start shelling out money on pieces that are not related to the problem. Any help would be greatly appreciated!
 

waste

TFP Expert
LifeTime Supporter
Mar 29, 2007
4,160
Coastalish 'down easter'
Hey again :wave:

Let's take it back to basics, have you killed the power to the unit for ~ 30 seconds (that will reset the processor)?

What you can do is trace all the wires and make sure they're all connected and in good shape.

If you do that and all is good, you need to find the guy who helped you last year. (folks that are planning on leaving the pool co. they work for will usually leave their # with customers :| )

I'll help you as much as I can but it seems like the dude you had last year is gonna be better than me
 

volkg35

Member
Aug 3, 2010
20
waste said:
Hey again :wave:

Let's take it back to basics, have you killed the power to the unit for ~ 30 seconds (that will reset the processor)?

What you can do is trace all the wires and make sure they're all connected and in good shape.

If you do that and all is good, you need to find the guy who helped you last year. (folks that are planning on leaving the pool co. they work for will usually leave their # with customers :| )

I'll help you as much as I can but it seems like the dude you had last year is gonna be better than me
Thanks for the reply!
I cut power from the circuit breaker for the entire pool system for about 1 minute, then powered the system back up with no luck. All of the wiring looks to be in great shape. I actually have my pool guy's cell phone number but it goes straight to voicemail. I spoke with the company he works for and they seem to be a bit frustrated when I ask for him and they say they haven't been able to contact him or his family for almost a month now (I'm hoping nothing tragic happened to him). Anyways, my next step is to get a hold of a voltmeter and see if the safety switches are getting any juice. A look at the wiring schematics looks like if the thermostat relay or thermostat itself is shot then the other components won't get juice since they all seem to be set up in a series (i could be wrong on the schematics though). I'm assuming since all of the lights went out at once and the tstat is the next in line of the series after the power light, it might be the culprit. Any other thoughts?
 

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