Pentair MaxETherm 400K BTU Heater issues

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XsAllOverIt

XsAllOverIt

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Dec 8, 2010
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Mount Airy, Maryland
We started our new Pentair MaxETherm heater in December. It runs full-time at 70 degrees which I would suspect is not a real load on a new heater like this. Initially it had a crack in the bottom section and leaked. They fixed that. Now it's not running. It's got a high pitched sound when it's trying to start. Anyone else have issues with a new heater? SO FRUSTRATING to go 2 months with new equipment to result in no use of the hot tub again until it gets fixed. No diagnostic information on the panel on the heater. I've looked everywhere. It's natural gas and as far as i can tell, it is receiving gas. When I started it up, ran to the meter and it sounded as if gas was being requested from the heater for the short period of time that the heater attempts to start.
 
Sounds like the reason it's not firing is either the hsi is broken or the module is bad not sending power down to the hsi... I have installed many lately where the module went out in the first couple of weeks... The noise does it sound like it's coming from the fan like metal on metal..
 
The crack that was fixed is odd unless it was dropped. That might have caused additional issues. When shipped, they box it very securely. This heater was one of the biggest reasons Pentair and Sta-Rite merged. It's rock solid.

Is the whistling sound different from the fan or is it the fan?

What size is the gas meter? Was it upgraded when you installed the heater? If you used NG for cooking, drying clothes, heating, and making hot water before and then added the heater, chances are you need a larger meter that can deliver the added supply demand of the added load of the pool heater.

As an example, my home's meter can deliver 250K BTUs. I didn't want to run the gas line (long run!) so I went with propane. Had I not, I would have had to have my NG company up size my meter to be able to handle the added 300K demand of my pool heater.

How much 3/4" pipe is at the heater? It should be less than 5' before it goes up in size. The increase in pipe size is usually dictated by the distance from the meter. The further away, the fatter the pipe needed.

Scott
 
Boy does this sound familiar! I'll be pulling the HSI on mine later today to check it.

Scott and Keven are giving good advice (which has helped me as well). This is a solid heater (mine is almost 9 years old, and this is the first "problem"). Ted (waste) also had me check the Fenwal (It is located behind the metal box in heater. Pull the shroud and then the screws on the box and take a look at it when you fire the heater. It will flash a series of "codes" if it is bad).

Good luck!
 
I called the pool builder yesterday but they haven't come to check it yet. It's going to snow 5-7 inches tonight. How long do I have if I go below freezing on this if the pump is running full-time?

Answers to several questions above:

[The noise does it sound like it's coming from the fan like metal on metal]
Yes, it does sound like it's coming from the fan and it's somewhat of a high pitch sound that goes on for 15-30 seconds before the service light goes on. Not sure what an hsi is?
[What size is the gas meter?]
Gas meter shouldn't be the problem. It's been running for 2 months solid. Also the meter was upgraded to 2# and the plumber that installed it certainly knew what it needed. We only have auxiliary heat other than the 400K heater, so I don't believe this to be the issue in any way. I believe it is getting gas to the heater sufficiently based off the last 2 months of work.
[Ted (waste) also had me check the Fenwal]
I'll do that tonight. I had looked for LED's last night with no success. I think I know where you are talking. I saw some red flashing from the top edge of that box last night. For the record, I HATE diagnosing electronic Crud. I can build a house, I can do plumbing, electric, woodwork, landscaping, etc, but can't figure out when something goes wrong with an electronic board.

What is an HSI???
 
HSI is hot surface ignitor... If you pull the dome off where your controls are on the board there is LEDs for troubleshooting also... Still my bet will be ignition module...
 
Do you know how to pull that dome off. I've gone through the manual and can't seem to figure that out. We've got them darn stink bugs everwhere and had one near the LED lights on the dome underneath at the beginning. I couldn't figure out how to get the dome off. I'm assuming when you say dome, the top area that has the led's for temp and pool/spa lights?
 
The dome comes off by pulling 2 clips on the underside of it. (a little detail- if you look at the underside of the dome, after first removing the cover [5/16" nutdriver is ideal for that], you'll see the plastic tabs from the dome coming through the topmost metal plate, 2 of these tabs have the retaining clips)

If you had an infestation of bugs, it could end up just being a shorted electrical connection (we used to FREQUENTLY! have to patch wires that mice chewed through on these units - mice seem to think of these as a nice condo to raise dozens of offspring in :rant: )

High pitched whining could be caused by an improper gas/ air mix, as Scott mentioned - I might be able to tell you how to adjust it yourself, but it's potentially VERY!! dangerous :hammer: so, if you think you have a gas flow issue, call in the gas guy :!:

I hope this ends up being a simple and inexpensive fix! Please keep us posted as to your progress.
 
Just so happens I am working on one right now.. Here is where the LEDs are located on the board..

4dfbadd7.jpg
 
If the heater whistles for only a brief 3 to 5 seconds, while the gas valve is open, then it sure sounds like a gas delivery/mixture problem. If it had been running i would say maybe you had a variance in your service pressure. You may had been running on the threshold of sufficient flow, then the variance dropped you below it. Note: I have only heard of this, from an old PG&E guy who was probably feeding me hooey. Never witnessed it. Only way to tell for sure is with a manometer.

You may want to check your gas meter anyway. If you have the 400K btu heater, that is AT THE VERY LEAST you need in a gas meter. Most homes (around here) will get you a 250 btu meter, which is more than enough, as long as you don't have a pool heater!

One way to check the HSI:
After you try to fire it a couple of times, SLOWLY slide your hand over the sheet metal and underneath the gas valve. As you slowly slide your hand toward the center of the heater, feel if the sheetmetal is getting warmer. This will tell you if the HSI is heating up/ working.
 

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I found the panel and LED's. No LED's lit up on the board when it went through the process. I really don't think it is a pressure problem. We have a 2# meter that was upgraded specifically for the pool heater. The line is about 50' to the pool house. The only other thing used in the house is auxiliary heat for our heat pump. I'll test the HSI to see if it's hot tonight. In the Fenwal, I'm getting the diagnostic light to light in 3 bursts full-time when it tries to start which indicates "Ignition Lockout". The heater never whistles. I'm getting a grinding noise.
 
XsAllOverIt said:
The heater never whistles. I'm getting a grinding noise.
Click to expand...

Grinding noise? Something is up with the blower, and thats why it wont light. Im guessing that the blower grinding is dragging, and keeping the blower from getting up to speed, and that means not as much air, and that will affect the (air fuel) mix enough to keep it from firing.

Since the heater is new, this is warranty, and you should call Pentair, if your installer isn't a warranty station.
 
Well, we got the pool builder out yesterday and he had to have a plumber come back with him today. They came out and indicated it was a bad valve on the unit and replaced it. When I go through the troubleshooting schematics with the symptoms, i didn't get to that route. After the thread, I opted to purchase an igniter module for hopefully the long-term future. It's something that could come in handy 4 years down the road in a blizzard - who knows... I have to mention that after taking the top off, I discovered about 100 stink bugs hibernating under the board itself. That shouldn't ever be an issue in the future since the unit is in the pool house. They are everywhere. I've got my fingers crossed for future functionality on this specific unit.
 
He said he was a warranty station and it's fixed, I'm happy. I would think he should be fully responsible for it since it's only run for one month. We'll have to wait and see if I get a bill. Just wish I knew enough about electronics. Thanks for all your replies guys. I learned a little.
 
Just as an add on to this thread. I had checked the water on the day I discovered the problem with the heater (Day 1). I checked the next day (Day 2) and all was well. PB came to check on the heater on Day 3 and fixed it on Day 4. On Day 3, he backwashed my spa (660 gallons) and never told anyone. Didn't add water either. Day 4 they fixed the heater. I came home that night late so never checked the spa. Checked next morning and discovered that the water was below the jets. I instantly called/texted PB to ask if they had backwashed. He said yes. I asked why he didn't tell either of us (Fiancee was home both days). He indicated he told her both days that the spa was low. Fiancee indicates that he never told her anything. I hung up. I've got several more committments from him, but I've got to tell you, what a nightmare build on our pool. Hope it all works as time goes on, because I don't want to deal with this guy any longer. Lied from Day 1 and many,many,many times from that point forward.
 

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