Pentair Mastertemp 400 CLUNCK

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Kbendon

0
May 27, 2011
11
Just went to start up my Master temp 400 heater and it ignites fine after about 45 seconds it makes a clunk and shuts off (ignition) the temp on the control panel goes from 50 to 120 and then back down to 50 and then it restarts the process and ignites again. Anyone have any ideas what this is?:confused:

I have this on video

http://s1203.photobucket.com/user/Kbendon/media/Mobile%20Uploads/35D7C06B-DAFE-40D6-BCF9-CA2E9670CFB9.mp4.html
 
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Sounds like the unit is hitting its high temp limit. Either there low water flow to the heat exchanger or the blower fan is not working. Are you getting any error codes from the display?


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 
Sounds like a bad regulator, broken bypass valve or both. Remove the thermal regulator and if it's all gunked up, replace it. If it will not pull out, bypass is broken and preventing you from removing the regulator. If you do get it out you should be able to stick your fingers inside the opening towards the top and feel what is like a round object. If you don't feel it, it's gone and you need to replace it.

So check those things out and let us know.
 
I spoke to soon worked fine the other night. Clunk is gone but now it is doing the same thing with temp panel and shutting off and restarting. Back panel has led8 on. Need help again.
 

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With the bypass valve set like it is, there is too much water going through the bypass and not enough going to the heater.

I also suspect that there is a problem at the heater. Possibly a clogged heat exchanger. Or, possibly a bad internal bypass. If the regulator was corroded, then the spring on the internal bypass is probably bad as well. This would allow too much water to bypass the heat exchanger. You can see the internal bypass when looking in the top inlet port.
 
When you replaced the regulator, did you check with your fingers if the bypass was still there? It should feel like a round disk located about a few inches inside the opening towards the top.
 
Bypass.jpg

That appears to have solve my issue - new on the left old on the right. Cycled on ran up to stat setting of 98 and cycling on and off now.


Been struggling with a very similar problem on my Mastertemp 300 that started with cutting out on HLS. Checked thermo-regulator first which turned out may have been the original source of the clinking - a small piece was gone. Thought I was good with new TR but again the heater came up ran a few minutes and shutdown service heater light came on with HLS lit - service heater light drops and heater cycles. Pulled all the sensors in the bypass manifold and cleaned them up and re-installed. I found a small leak in the manifold housing (hairline crack) so I replaced that - little costly but it made me take it off and inspect the insides of the manifold including the bypass valve assembly which isn't much more than a spring and a metal piece like a cross hair. Didn't see any build up of calcium it actually looked very good. I put a hose on each opening of the copper heat exchanger and flushed them and flow seemed good on each tube. Installed new manifold with new thermo-regulator and clean AGS, TC, and HLS. Same issue so I figure from other posts that the HLS is the last piece which unfortunately after replacing with new today the issue continues. I replaced the main board on the top part of the unit last summer and it has been working fine. Stack temp is good at 275. Thought possible issue with filter media and possible variable speed issue on the pump so I pulled the media and ramped the VS motor up to max speed brought system up. Heater still cycles like I have done absolutely nothing to the unit. I see the HLS cutout is at 135 degrees so with my digital thermometer (Fluke), I put the temp sensor on the housing very near the HLS, insulated it with 1" foam and watched it through the short cycle - it reached a surface temp of 124 degrees so my thought is something within that manifold assembly is not allowing for a proper mixing of the water circuit which is kicking the HLS out. The inspection of all pieces looks very clean so really perplexed. I could really use some help on this.

**Figured out what is wrong - reviewing the parts breakdown from manual I see there is more to the bypass valve assembly than just a spring and a cross hair looking part. It appears that the guts have broke away from corrosion over time and chemicals - unit is 7 years old. That explains the overheating of the water and the unit kicking off on HLS. Part should be here on Saturday - will update on status to see if this is the fix.**
 
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