Mastertemp 250 Heater Service and Maintenance

[Andy SD]

The Service Heater LED turned on for a few seconds the last time I fired up the heater (HTR 250 MASTERTEMP NA - 460732 - 2019), so I figure it's time to do some diagnostics and maintenance on the unit. I've search around a bit here, and come across some good info, and just wanted to actually join the community and make sure I have this all straight in my head...

I haven't tried to fire it up again since, but the troubleshooting section in the manual does say to pull the pull the control panel and look for diagnostic LEDs. Are those LEDs going to remain lit even though the Service Heater LED turned off (ie- does the board maintain error code state)? Or am I going to have to try to get the Service Heater LED to come back on? Does the heater need to be on or actively heating for the diagnostic LEDs to be on?

I am planning on taking the heater completely out of the loop so I can work on it and keep the pump and filter running. I got some unions, and I'll make a "U" shaped PVC piece, as I don't have heater bypass.
With the other side of those unions, I'll make some pieces to connect a submersible pump to and run some CLR (or MA if it's real bad) to descale the heat exchanger. The previous owners of the house did not keep the pool chems in balance, so I am aware this could lead to a full replacement of some of the heater parts if they are too far gone. I have seen some mention of removing a bypass valve when doing that, but I can't find anything concrete on that. Looking at the parts diagram, I see what's called out as a Manifold Bypass Valve, as well as a Thermal Regulator. Looks like I'd have to remove the whole Manifold to get to the bypass valve.

Are there any parts I should just order ahead of time?

I also recently rebuilt the pump- new seals, impeller, diffuser, mechanical bearing, pulled the motor apart and replaced the bearings, repainted the motor, etc.. I'm willing to do things right, and I have all the tools on hand to most anything necessary.

 

[ajw22]

.Are those LEDs going to remain lit even though the Service Heater LED turned off (ie- does the board maintain error code state)?

No.

Or am I going to have to try to get the Service Heater LED to come back on? Does the heater need to be on or actively heating for the diagnostic LEDs to be on?

Yes.

. Looking at the parts diagram, I see what's called out as a Manifold Bypass Valve, as well as a Thermal Regulator. Looks like I'd have to remove the whole Manifold to get to the bypass valve.

Correct.

Are there any parts I should just order ahead of time?

If you are removing the manifold then get the manifold O ring kit and replace all the O rings on the neat exchanger pipes.

Have you opened the manifold and looked at the condition of the heat exchanger before you begin spending money on parts?

I would build the Heater Bypass - Further Reading now.

 

[Andy SD]

Have you opened the manifold and looked at the condition of the heat exchanger before you begin spending money on parts?

I would build the Heater Bypass - Further Reading now.

Thanks for the response.

I haven't opened the manifold yet. I am still in the fact finding / discovery process of how to work on this unit.

I don't want to change the plumbing at the moment. I have a larger project planned for the late fall to pour a proper concrete pad for the pool equipment, as the induvial pieces are supported by random bricks at the moment. Whoever installed this stuff originally didn't do a great job. I'll redo the plumbing at that time, and add in a bypass for the heater at that point.

I'm ok with replacing the whole exchanger if this one too far gone.

 

[Andy SD]

I still have been able to find a concrete answer on whether or not I need to remove the bypass to descale the exchanger- the YT videos don't mention it at all.

 

[ajw22]

I still have been able to find a concrete answer on whether or not I need to remove the bypass to descale the exchanger- the YT videos don't mention it at all.

Show us a picture of how much scale you have in the heat exchanger.

 

[Andy SD]

I hear you loud and clear- it's not worth descaling if it's in too bad of a condition. But... as someone who just joined this forum looking for help, it's really frustrating that you're gate keeping procedural information, based on the condition of the exchanger. It's extremely off putting, and I hope that does not speak to the general attitude of this community.

As I stated before, I haven't opened the manifold yet. I haven't even taken the heater out of the loop yet. I am trying to learn about and understand the process so I can gather the items I need to do the work.

 

[JamesW]

I still have been able to find a concrete answer on whether or not I need to remove the bypass to descale the exchanger- the YT videos don't mention it at all.

No, you do not need to remove the bypass.

You should remove the thermal regulator.

 

[JamesW]

You can connect to the unions or you can unscrew the unions and use threaded fittings.

You can use hydrochloric acid or a product made for descaling.

https://www.supplyhouse.com/Oatey-35230-Haymaker-Descaler

 

[JamesW]

Undo the unions, unscrew the union adaptors and look into the holes to see what is visible.

 

[JamesW]

But... as someone who just joined this forum looking for help, it's really frustrating that you're gate keeping procedural information, based on the condition of the exchanger.

AJW22 writes most of the articles here:

Further Reading

www.troublefreepool.com

So, it is really not fair to say that they do not provide procedural information.

They actually provide the most information of anyone and make it accessible and useable.

 

[ajw22]

But... as someone who just joined this forum looking for help, it's really frustrating that you're gate keeping procedural information, based on the condition of the exchanger. It's extremely off putting, and I hope that does not speak to the general attitude of this community.

I don't know why you think I am gatekeeping anything.

Anyone can join and contribute to your thread.

I am trying to point you in the right direction.

All I know is in Pentair MasterTemp Heaters - Further Reading

 

[Poolbreh]

I didn’t think ajw22 was gatekeeping at all. He’s trying to steer you on the right path and not jump to conclusions. He’s a volunteer and has helped thousands diagnose their heater. He’s written a lot of the articles that I forward to people that work in the field to help with their diagnosis. He is a gem of this community.