Pool Opening Spring 2025 - Removing the Leaking Heater Manifold

[ajw22]

I decided I had nothing to lose by digging into the heater and seeing if the manifold can be removed. First discovery was the bolt heads were so rusted that the edges crumbled with a socket on them. Wrenching them out was not going to work.

After considering options the decision was to cut the bolt heads off using a grinding wheel.



This problem demonstrated the advantage of having a heater bypass. I was pleasantly surprised to see that the diverter valve and check valve did not leak when the pump was running.

It is interesting that if the filter pump stops the check valve flap loses its seal and begins leaking. The water pressure on the flap is what maintains the water tight seal.The spring tension is not adequate when the pump shuts off and air can be sucked in from the open check valve.

I disconnected the pipe unions, electrical wires, and gas line so we could move the heater to get better access to the bolts. It also showed how much crud is under the heater and will get a cleanout. You will notice I removed the actuator from the heater bypass diverter. I did not want the actuator to inadvertently turn which would send water out the open pipe.

One bolt head is off in the picture below.



It took about an hour with the grinder and went through three grinding wheels to remove the four bolt heads. The other bolts wrenched out without any problem.

Kroil Penetrating Oil was used liberally on all the bolts to loosen them,. Highly recommended...

Kroil - The Best Penetrating Oil, Degreaser, and Fuel Additive

Kroil Original - The most trusted penetrating oil since 1939! Choose from Kroil Original Penetrant, Kroil Original Penetrant Aerosol FormAT (AeroKroil), or Silikroil (Kroil Penetrant with Silicone).

www.kroil.com

A pipe wrench was used to grip the bolt stems. With patience and force three unscrewed cleanly.



The second bolt from the bottom broke and you can see the stem in the picture below. I think there is enough to grip it with the right tool and more soaking with Kroil.



This is as far as I got today. I think it was a success getting the manifold removed. A new 77707-0016 GENUINE Pentair Manifold Kit Max-E-Therm MasterTemp 400 is on order and it comes with new sensors, bolts and O-rings.

There is no scale on the 10 year old heater and the copper heat exchanger stubs look in excellent condition with little wear. The burner can and lid show no signs of rust.

It looks like I can get a few more years out of this heater. I am optimistic we can get the broken bolt out of that hole. And if we cannot get the bolt out my plan is install the new manifold with nine bolts and hope it holds sufficiently tight that one is not missed.

Stay tuned for updates. This has become an interesting project.

 

[dleonard1122]

I decided I had nothing to lose by digging into the heater and seeing if the manifold can be removed. First discovery was the bolt heads were so rusted that the edges crumbled with a socket on them. Wrenching them out was not going to work.

After considering options the decision was to cut the bolt heads off using a grinding wheel.

View attachment 639590

This problem demonstrated the advantage of having a heater bypass. I was pleasantly surprised to see that the diverter valve and check valve did not leak when the pump was running.

It is interesting that if the filter pump stops the check valve flap loses its seal and begins leaking. The water pressure on the flap is what maintains the water tight seal.The spring tension is not adequate when the pump shuts off and air can be sucked in from the open check valve.

I disconnected the pipe unions, electrical wires, and gas line so we could move the heater to get better access to the bolts. It also showed how much crud is under the heater and will get a cleanout. You will notice I removed the actuator from the heater bypass diverter. I did not want the actuator to inadvertently turn which would send water out the open pipe.

One bolt head is off in the picture below.

View attachment 639591

It took about an hour with the grinder and went through three grinding wheels to remove the four bolt heads. The other bolts wrenched out without any problem.

Kroil Penetrating Oil was used liberally on all the bolts to loosen them,. Highly recommended...

Kroil - The Best Penetrating Oil, Degreaser, and Fuel Additive

Kroil Original - The most trusted penetrating oil since 1939! Choose from Kroil Original Penetrant, Kroil Original Penetrant Aerosol FormAT (AeroKroil), or Silikroil (Kroil Penetrant with Silicone).

www.kroil.com

A pipe wrench was used to grip the bolt stems. With patience and force three unscrewed cleanly.

View attachment 639592

The second bolt from the bottom broke and you can see the stem in the picture below. I think there is enough to grip it with the right tool and more soaking with Kroil.

View attachment 639594

This is as far as I got today. I think it was a success getting the manifold removed. A new 77707-0016 GENUINE Pentair Manifold Kit Max-E-Therm MasterTemp 400 is on order and it comes with new sensors, bolts and O-rings.

There is no scale on the 10 year old heater and the copper heat exchanger stubs look in excellent condition with little wear. The burner can and lid show no signs of rust.

It looks like I can get a few more years out of this heater. I am optimistic we can get the broken bolt out of that hole. And if we cannot get the bolt out my plan is install the new manifold with nine bolts and hope it holds sufficiently tight that one is not missed.

Stay tuned for updates. This has become an interesting project.

A little bit of heat, penetrating oil, and some vice grips and you'll have that last bolt out in no time. Subscribed to follow along.

 

[ajw22]

Added 8 bags of Aquasalt yesterday and Intellichlor is saying salt is 3350.

Water temperature hit 58F this morning, the Cold Water Shutoff cleared, and SWG started generating. Water temperature now 60F and we will see if it generates through the nights.

 

[Lake Placid]

FWIW…..follow the torque sequence and specs when installing the new manifold. I replaced the manifold on a max e late last year and the new manifold leaked out of the box. Keep eyes open and don’t discount broke when delivered even if brand new pentair merch.

 

[ajw22]

FWIW…..follow the torque sequence and specs when installing the new manifold.

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/max-e-therm/manuals/maxetherm-heater-manifold-replacement-manual-english.pdf

I replaced the manifold on a max e late last year and the new manifold leaked out of the box. Keep eyes open and don’t discount broke when delivered even if brand new pentair merch.

Was the crack or defect visible? I intend to look over the manifold and parts received when I get it.

 

[PoolStored]

ATF-Acetone is your huckleberry.



Standards for 1/4-inch or 5/16-inch stainless steel bolts are a torque range of 10–15 ft-lbs (13.6–20.3 Nm). Amazon.com

Start at 50%, 5 ft-lbs and work up in 25% increments. The next increment would be 7.5 ft-lb. Then final torque...or you can do 10, then 15.

You have left and right 1-5, call it 1 (top) to 5 (bottom). Proper sequence, repeated up to 10-15 ft-lb would be:
L3, R3, L4, R2, L2, R4, L1, R5, L5, R1
Start at the center and work up and down.
After completing the sequence, go through the pattern again to ensure no bolts have loosened due to gasket compression.

Edit: didn't see your post until after mine. Sequence is right, torque at 10 Ft-lbs is right.

 

[Lake Placid]

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/max-e-therm/manuals/maxetherm-heater-manifold-replacement-manual-english.pdf

View attachment 639956


Was the crack or defect visible? I intend to look over the manifold and parts received when I get it.

Nope, the crack or failed area wasn’t obvious upon visible inspection. The manifold was just dripping water when I restarted the system. I retorqued multiple times and it wouldn’t seal. Memory serves I couldn’t tell if it came from the #21 zinc plug (on the ipl) or elsewhere on the manifold, so I gave up and defected it with my supplier. The second one was fine. You’ve got the correct install manual with torque sequence.

 

[ajw22]

Nope, the crack or failed area wasn’t obvious upon visible inspection. The manifold was just dripping water when I restarted the system. I retorqued multiple times and it wouldn’t seal. Memory serves I couldn’t tell if it came from the #21 zinc plug (on the ipl) or elsewhere on the manifold, so I gave up and defected it with my supplier. The second one was fine. You’ve got the correct install manual with torque sequence.

Hopefully I will not run into that. Harder for a retail Internet customer to defect it after installation when ordered from a pool store in California.

 

[ajw22]

ATF-Acetone is your huckleberry.

Well I was using almost the best stuff. Will see how ATF-Acetone works. Thanks for the tip.

I have half the brew and it is Pro Strength. May need to siphon some ATF from a car…

 

[JamesW]

6.25 ft-lb to 9.58 ft'lb. is what is specified.

 

[JamesW]

https://sanjuanpools.com/catalog.pdf

 

[ajw22]

Interestingly, the new manifold has all new sensors installed except for the thermal regulator, spring, and cap. They expect you to remove the thermal regulator, spring, and cap from the old manifold and reuse it.

Below is what my thermal regulator looks like after 5 years in service. A replacement is on order.

It is also interesting that the cost is just about the same for the thermal regulator alone and for the thermal regulator kit with the spring and cap.

 

[Lake Placid]

It is also interesting that the cost is just about the same for the thermal regulator alone and for the thermal regulator kit with the spring and cap.

Usually a $20 difference

 

[ajw22]

I am pleased to report my heater is now back together and working like new. It took around eight hours of work over three days, $600 in genuine Pentair parts, and about $150 in new tools.

If you had all the parts and tools and no broken stuck bolts the repair could have been done in under four hours.

The Manifold Replacement instructions contain this warning to be careful once the bolts are removed to not push the tube sheet into the combustion chamber.

To get the stuck bolt out it took some drilling and then tapping the threads to clean it up and take a new bolt.




I was concerned the work risked pushing the tube sheet into the chamber which would complicate things.

I bought some nuts that fit on the removed bolts and used them to secure the tube sheet from moving. Pentair should recommend that in the instructions.





With the heat exchanger tube sheet being secured, the stuck bolt was removed, and the area was cleaned as the instructions specified.

From there it was all downhill, installing the new manifold and torquing the bolts. We went over the bolt sequence over a dozen times until the torque wrench clicked on every bolt.

Got the heater back in place, and reconnected the electrical wires, gas line, and water pipes. Started the pump to get water flowing through the manifold to check for leaks. Oops, needed to tighten up the thermal regulator cap and drain plug.

And then as @Lake Placid warned Pentairs QC was not perfect. There was a drip from the 3/4" drain plug on the side. Wrenched that out and saw that the threads were hardly wrapped with Teflon tape. Removed Pentairs tape and put two good wraps of Telon tape, reinstalled, and no drips.






Time to flip on the breaker, power up the heater, and see if it will light.

Pushed the buttons, the control panel lit up, and I got SERVICE HEATER without the blower starting.

 

[ajw22]

When I reconnected the Fireman's switch wires in the electrical box, I saw that a red wire was unconnected.



There was no obvious terminal missing a wire, so I figured, let's move on, put it all together, and see what happens when we start the heater.

That led to the SERVICE HEATER LED. I removed the four wing nuts on the cover, which let me flip the cover over and see the diagnostic LEDs. Sure enough, the AFS LED was on. This made sense since the blower did not start.

Now, we need to figure out why. With the cover off, checking the airflow switch and its connections was easy. They all looked good.

Now for that loose red wire. With the cover off, I could follow the wire out of the electrical box and see it connected to the blower motor.

Pentair was smart enough to put the entire electrical connection diagram inside the door. That let me see that the blower's red wire in its harness connected to the right-side terminal bar. On that terminal bar, there should be two white wires and two red wires. Sure enough, one red wire was missing.



I put the red wire on the terminal block, closed it up, and the heater started.



While I was renovating the heater, I replaced all the missing nut plates and screws that got lost over the years that hold the side panels on. I got the top cover and side panels closed up and installed the new thermal regulator.

It has been three weeks since the pool was opened, and I think I have all the problems fixed.

Next is to update my IntelliCenter to Version 3 firmware.

 

[Lake Placid]

And then as @Lake Placid warned Pentairs QC was not perfect. There was a drip from the 3/4" drain plug on the side. Wrenched that out and saw that the threads were hardly wrapped with Teflon tape. Removed Pentairs tape and put two good wraps of Telon tape, reinstalled, and no drips.

You found another common leak from the factory….they neeed a new plug installer guy on the assembly line.