Pool Opening Spring 2025 - Removing the Leaking Heater Manifold

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.

img_0272-jpeg.639172


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

MasterTemp Grinding Bolt Head.jpg

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.

MasterTemp One Bolt Head Off.jpg

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...


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

MasterTemp Manifold Off.jpg

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.

MasterTemp One Broken Bolt.jpg

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.
 
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.

img_0272-jpeg.639172


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...


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


1745373682709.png

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.
 

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  • maxetherm-heater-manifold-replacement-manual-english-1.pdf
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ATF-Acetone is your huckleberry.

1745373569775.png

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.
 
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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👍.
 
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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.
 
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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…

IMG_0346.jpeg
 
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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.

IMG_0286.jpegIMG_0287.jpeg