Pentair Mastertemp 200 - Loud Heater Whine

[OH330]

Hi all,

This is my first post but I've been reading these forums for about a month now. We own a pool that was not taken care of very well for several years and have been on a mission to fix this heater. It all started with an E05 error that required us to replace the stack flue sensor, control board and membrane pad to get it running. We also replaced the thermal regulator for good measure. The unit functions but now has a loud whine while it runs. I've seen posts about bearings for pumps but not sure what to make of this from the heater itself. Below is a youtube video I recorded so you can hear it.

https://www.youtube.com/watch?v=GqSzqM6CrtU

I look forward to your advice and thank you in advance!

 

[ps0303]

Could be several things. First I would remove the front and back panel and check the air orifice, it's a round cone that allows air into the blower motor. Make sure it looks in good shape as in my picture. Notice the honeycomb shape of the vent piece. Make sure it is intact. Run the system with the panels off and see if the noise is worse or better.


Have you had any changes in your gas delivery system?

 

[OH330]

Hi ps0303,

I appreciate the quick reply. I removed the covers and it is definitely louder. The air orifice you described appears to be in good shape just a little dusty. I've uploaded another video so you can hear the whole startup process and see the part. (I should have done that in the first place sorry.)

https://www.youtube.com/watch?v=0fSyNZ0QHxg

There have been no changes to the gas service that we are aware of. This is our first season with the pool.

Thank you!

 

[randytsuch]

I'd have to guess the heater blower motor bearings.

 

[OH330]

Hi randytsuch,

The blower model number for the unit is 77707-0251. I checked the Pentair manual and I don't see any bearing kits; only whole blower replacement kits for around $400. Do you know if they are replaceable on their own if I were to tear it apart?

Thank you!

 

[ps0303]

It does not sound like the blower motor issue. That sounds like it is a water flow issue. Are you sure you have plenty of water flow?

If it were the blower motor, you would need to replace the entire blower motor. No serviceable parts in it.

 

[JamesW]

Pull out the thermal regulator and see if the noise is still there.

The noise happens right about when the thermal regulator should open and maybe it's only opening a crack and creating the noise.

 

[randytsuch]

I'll defer to these guys, they know a lot more than I do.

 

[JamesW]

The thermal regulator looks like this:

Pentair Sta-Rite 77707-0010 Thermal Regulator Kits on Sale at YourPoolHQ

There's a plug between the inlet and outlet to the left. Turn off the pump and unscrew the plug. The plug holds the thermal regulator against the exchanger outlet using the spring.

Pull out the spring and thermal regulator assembly and then reinstall the plug.

Start the heater to see if the noise is still there.

The thermal regulator keeps water from exiting the heat exchanger until the heater fires and the water warms up.

The regulator is temperature activated and opens when the water gets hot.

The reason for the regulator is to prevent condensation from building up on the exchanger and dripping into the combustion chamber from cold water constantly circulating through the exchanger when the heater is not on.

If the noise goes away, replace the thermal regulator. Reinstall the old regulator and keep the heater turned off until you replace the thermal regulator.

 

[OH330]

I pulled the thermal regulator and it runs quiet... I mentioned that we just replaced that part. Is there something internal in relation to the thermal regulator that responds to flow/pressure?

I ask because we purchased a "pool roomba" and it moves very very slow (the instructions say it could be a flow/pressure issue). We planned on changing the media in the sand filter this weekend to see if that helped the "pool roomba". Maybe we can kill two birds with one stone!?

Thank you!

 

[JamesW]

The thermal regulator opens based on temperature. I think that the noise is from water moving through the thermal regulator but I don't know why it's happening.

Maybe the thermal regulator isn't opening enough or the water flow is too high or too low.

Maybe a picture of the system would help along with some specifics about the pump and filter pressure.

 

[ps0303]

Sounds like a water flow issue. If the thermal regulator is new, then I would think it is in good operational condition.

 

[JamesW]

Since the noise goes away with the thermal regulator removed, it seems like it's the cause of the noise.

I think that it's a whistle type effect from excessive water velocity through an opening.

I think that it's either the thermal regulator not opening correctly or the water flow through the exchanger is too high.

Maybe an oversized pump or something wrong with the internal bypass.

 

[OH330]

When I re-installed the thermal regulator the noise has gone down slightly but is still fairly loud. Below are pictures of the pump, filter and intake of the heater. From what I'm seeing online everything should be at a max psi of 50. Does that sound appropriate?

We don't know when the last time the sand was changed. It has been at least 5-8 years so I think that is a good place to start. I double checked all of the valves and they all appear to be fully open. If the sand doesn't help maybe we look at the bypass you mentioned?

Pump = Century A.O. Smith UST1102 56J C-Face 1 HP Single Speed
Filter = Hayward Pro Series S210T
Heater = Pentair Mastertemp 200







Thank you!

 

[JamesW]

Ok, your pump is not oversized. The only thing that I can think of is the thermal regulator is not opening correctly.

I wouldn't worry about the sand. It almost never needs to be changed.

What is the filter pressure?

Do you have a picture of the whole system?

 

[OH330]

The pressure is almost always between 10 and 15. We backwash at 20. The site is struggling with letting me upload the picture I took of the system. Ill have to resize it later. All 3 are within 3-5 ft of eachother.

 

[JamesW]

You get limited pictures unless you're a supporter. Maybe delete the old pictures or upgrade by becoming a supporter or post to a host site and link to the pictures.

 

[OH330]

So I donated today but cant upload more pix... A moderator must have to change my user level. I'll have to wait to upload mages; until then...

I replaced the sand against the recommendation above because I was wrong it had been over 10 years. There were more than a few hunks that needed broken apart to get them in the shop vac so I think it was worth it for only $100. There is only a slight difference in pressure/flow at least for the pool roomba. We timed it and it only moves slightly faster than it had previously. The sound remains but again is not as loud as before I reinstalled the thermal regulator.

Something to consider is that the old thermal regulator made this same noise before we replaced it. Would else could be causing a pressure/flow issue and is there a good way to test it without an inline tester?

This video is the startup sequence now so you can hear the difference from the first video.
https://www.youtube.com/watch?v=5pQNtx1zowI

This video shows the setup and the pool as you requested.
https://www.youtube.com/watch?v=QEAeSAAghn4

Thank you as always!

 

[JamesW]

I don't know why it's making the noise.

Maybe check the internal bypass and make sure that the inlet and outlet are not reversed.

 

[ps0303]

I wonder if you have a blockage in the heat exchanger. You would need to remove the manifold to see what the tubes look like. While at it, you can check the bypass inside. It is just a classic dying for water sound.