Pentair MasterTemp 250, Low Flow on my SWG with Thermal Regulator Installed

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Z

ZSK

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May 29, 2012
36
Looking for some help. I didn't have this issue last year, but the last few weeks I noticed my IC40 SWG show "red" no flow when I install the Thermal Regulator on the MasterTemp 250 heater and my pump speed is set to low.

I tested the thermal regulator in some hot water and it does open at 120 F. The SWG works fine on if my pump speed is set to high, but I don't run my pump on high most of the time. Any ideas? Seems like the thermal regulator or thermostat is causing enough restriction in my water flow to stop the SWG from running, and I also notice the water coming of the returns looks to be a lower flow rate.

Thanks for the help!
 
Quick update:

I see low flow on my IC40 with thermostat installed and the Heater: Off. When I turned the heater ON, the SWG switched on and no longer shows RED no flow. Any ideas? I really don't use the heater that much and just pulled out the thermostat, but I would like to try and figure out what's going on. Thanks
 
Did you remove the old regulator or was it missing when you went to replace it? Thinking maybe the clip rusted away thus allowing the regulator to float into the piping.

Also, how was the condition of the bypass?
 
What does the bypass look like and where is it located? The old regulator is fine and the clip and spring are in good shape. But now I'm wondering if it's the bypass....
 
Actually the bypass is inside and if it were broken it would only restrict flow into the heater. Was just curious if you checked it. It sits above the thermal regulator.

Is your filter clean?

How old is the SWG?
 
The cell works fine on high speed on the pump or with the pool heater thermostat removed. A quick update, with the pump on high and the thermostat installed I hear a faint "rattling" or metallic noise from the pool heater (when the heater is off).

I did run the heater for a few minutes and it seems fine and is heating correctly.
 

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The item in the picture is a thermal regulator not a thermostat. Its job is to properly mix cold and heated water in the heaters manifold to regulate the internal temperatures (oddly enough like a thermostat in a car). The heater shouldn't operate with it removed. It almost sounds like you have calcium deposits in the heater exchanger slowing the flow.

The internal bypass does sit above the thermal regulator and usually when broken it's very difficult to remove the thermal regulator as the plunger gets hung up on the regulators spring. You can check for its integrity by removing the regulator and sticking your finger inside. if you feel a hole above where the regulator sits the bypass is broken and very likely the plunger is sitting in the front of the cell which might cause your flow issues as that's the location of the cells flow switch.

GL!

EDIT: The heater has a high limit switch on the manifold that will not allow overheating as long as no one has bypassed the safety loop.
 
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Thank you for the detailed description! I can feel and see the internal bypass above the thermal regulator, it looks fine and seems to be intact. I think it's just my overall pumping that is restrictive and adding the thermal regulator is just enough to stop the SWG Cell flow sensor from closing.
 
ZSK said:
I'm posting the photos via my google drive, I'm over my quota limit on file uploads because of old post with photos attached.
Click to expand...

The tutorial I linked to give you an idea on how to make the photos (hosted on Google or where ever) show up directly in the thread ... take it or leave it. Looks like you are getting adequate help from people willing to navigate off the forum.
 
JoelFitz said:
The heater shouldn't operate with it removed. It almost sounds like you have calcium deposits in the heater exchanger slowing the flow.
Click to expand...

Yes the heater will operate without this part. It's not best to leave it out but it will run.

- - - Updated - - -

ZSK said:
Thank you for the detailed description! I can feel and see the internal bypass above the thermal regulator, it looks fine and seems to be intact. I think it's just my overall pumping that is restrictive and adding the thermal regulator is just enough to stop the SWG Cell flow sensor from closing.
Click to expand...

I have never seen the regulator restrict flow like you are having. There has to be something else that we/you are missing.
 
I'm guessing that the system(heater) used to work on low speed, otherwise you wouldn't be here. If not,, the invention of the 2 speed pump came long before the chlorine generator, therefore, no consideration was given to the design for flow requirements, of other appliances that were to come later. First stage is not that much flow, i think its somewhere around 1/8 or even 1/16 HP. So it wouldn't surprise me that this is happening.

Which may suggest that you "live with it?".

If so, Having said the above, the amount of flow that is gained by the T.R. opening and allowing the SWCG ot operate, may be that you have some kind of added restriction in the heater. And the little flow you gain when the TR opens is enough to allow operation. Perhaps as suggested earlier, a part came loose or broken, and has become lodged in a passage way, or as someone else had pointed out, a build up of calcium in the exchanger may have occurred.

If your SWCG had worked in the past on low speed, an investigation into the heater may be warranted if the filter turned out to be free of any un-necessary restrictions. There really isn't any other part in the system that would "gain" restriction over time like those two components can, other than the cell itself, who's flow switch, while upstream of the cell, could still be impacted by a flow reduction in the cell. So make sure that the cell is clear too.
 
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