Mastertemp 400 Shutdown Issue & E05 error

JamesW

TFP Expert
Mar 2, 2011
16,005
See the video. If you don't see the disk, do you see a hole?

If you push on the spring, you should see the disk moving in the hole where the thermal regulator goes.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
See the video. If you don't see the disk, do you see a hole?

If you push on the spring, you should see the disk moving in the hole where the thermal regulator goes.
Perhaps I’m missing something. I’m looking in the hole that the thermal regulator goes in (with spring for that removed as well). The picture attached is of that hole. All I see is the hole where the thermal regulator sits.
 

JamesW

TFP Expert
Mar 2, 2011
16,005
Look in the water inlet. Push down on the spring and you should see the disc get pushed into the hole where the thermal regulator is.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
Look in the water inlet. Push down on the spring and you should see the disc get pushed into the hole where the thermal regulator is.
Ok, finally got access to water inlet (see attached picture). It's really tight in there but when I pushed down on spring with a screw driver, I did not see anything where the thermal regulator goes. Any more thoughts? And, thank you again for all the assistance.
 

Attachments

JamesW

TFP Expert
Mar 2, 2011
16,005
Did you watch the video?

If you're not seeing the disc getting pushed into the hole where the thermal regulator goes, then it probably broke off.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
Did you watch the video?

If you're not seeing the disc getting pushed into the hole where the thermal regulator goes, then it probably broke off.
Ya, that's what I'm thinking. Just ordered a new kit and plan to take everything apart over the next two days. If that is the final solution, I'll be happy but this has been a journey! Thank you again. I owe you a few beers, at a minimum.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
One last sanity check before I take everything apart. Assuming the internal bypass is broken, does it make sense that the heater works seemingly perfectly with the thermal regulator removed?
 

JamesW

TFP Expert
Mar 2, 2011
16,005
The thermal regulator reduces flow through the heat exchanger. So, it makes sense that it would work with it out.

The internal bypass doesn't bypass all of the water.

I think that the internal bypass is probably bad.

If the plunger has broken off, it's probably going to be in the plumbing somewhere.

Can you see the hole where the plunger should go?
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
231
Spring Valley, NY
Ok, finally got access to water inlet (see attached picture). It's really tight in there but when I pushed down on spring with a screw driver, I did not see anything where the thermal regulator goes. Any more thoughts? And, thank you again for all the assistance.
If you look at the spring in the picture you can see the shaft running through the center of the spring. Does that mean that it's not broken as the spring is somewhat still compressed just like the youtube clip demonstrates.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
The thermal regulator reduces flow through the heat exchanger. So, it makes sense that it would work with it out.

The internal bypass doesn't bypass all of the water.

I think that the internal bypass is probably bad.

If the plunger has broken off, it's probably going to be in the plumbing somewhere.

Can you see the hole where the plunger should go?
Cool, thanks again. I'm going to go ahead and take it all apart to see what's going on. A new kit has been ordered and will be here tomorrow. Will report back!
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
If you look at the spring in the picture you can see the shaft running through the center of the spring. Does that mean that it's not broken as the spring is somewhat still compressed just like the youtube clip demonstrates.
It's really hard to see exactly what is going on so I think I'm going to go ahead and take it apart to find out.
 

JamesW

TFP Expert
Mar 2, 2011
16,005
When you look into the hole where the thermal regulator goes, you should be able to see the plunger disc or the hole that the disc covers.

Can you see the hole or feel it?
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
231
Spring Valley, NY
In the youtube clip after he assembles the valve stem with the spring and then mounts it back where it belonged ,he clearly states the back end stays off the wall. In this picture I can't say for sure but it looks like it is against the wall. That may be interpreted that the disc portion of it popped off leaving the back portion behind and that's why there's no space because the spring isn't limited by the length of the valve anymore.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
When you look into the hole where the thermal regulator goes, you should be able to see the plunger disc or the hole that the disc covers.

Can you see the hole or feel it?
I'll try to look again but it's really hard to see in there. And, too small a hole and too long a shaft to feel in there...
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
Ok, finally took everything apart and hope I found the culprit. The internal bypass is not broken but there is a piece of something (PVC pipe maybe?) that worked it's way in and wedged the disc open a bit (picture attached). I'm going to put it back together, fire it up, and see how she runs. Do folks think this could cause the heater to shut off?
 

Attachments

  • Wow
Reactions: JoyfulNoise

JamesW

TFP Expert
Mar 2, 2011
16,005
That looks like part of a de filter grid. You need to take the filter apart, clean the grids well, replace any damaged grids and recharge with DE.

Since there is debris getting to the heater, there might be debris stuck in the heat exchanger blocking water flow.

Scale can also reduce water flow through the heat exchanger and reduce heat transfer.

Overheating water is more likely to scale.

In any case, if the internal bypass plunger is stuck open, that can cause the problem.

The gap seems a little bit small to create the problem, but it's possible

Let's see what happens when you get it put back together.

Make sure that the flow is good.
 
Last edited:

freebsdrules

Active member
Sep 3, 2019
28
delaware
That looks like part of a de filter grid. You need to take the filter apart, clean the grids well, replace any damaged grids and recharge with DE.

Since there is debris getting to the heater, there might be debris stuck in the heat exchanger blocking water flow.

Scale can also reduce water flow through the heat exchanger and reduce heat transfer.

Overheating water is more likely to scale.

In any case, if the internal bypass plunger is stuck open, that can cause the problem.

The gap seems a little bit small to create the problem, but it's possible

Let's see what happens when you get it put back together.

Make sure that the flow is good.
Thank you! Going to put this back together and fire it up to see what happens. Next comes cleaning the DE Filter Grid and looking to see if any grids are damaged. Where is the heat exchanger and should I check there for stuck debris?
 

JamesW

TFP Expert
Mar 2, 2011
16,005

This is basically the same heater. You can see the holes going into and out of the heat exchanger when you have the manifold off.

There's no easy way to check in the heat exchanger for debris.

Maybe blow air through the tubes to see if anything comes out.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware

This is basically the same heater. You can see the holes going into and out of the heat exchanger when you have the manifold off.

There's no easy way to check in the heat exchanger for debris.

Maybe blow air through the tubes to see if anything comes out.
Thanks again. Heater is back on and working for now. Time to clean the filters and see what's going on there.

I think the above might be my limit. Not sure I have the time or patience to take all of that apart. If I can get a few more years out of this heater, that would be awesome.
 

freebsdrules

Active member
Sep 3, 2019
28
delaware
Ok, took filter apart and I don't think anything is broken but it is VERY dirty. Not sure the last time it was cleaned. Cleaned it up very well and about to put back together and add DE. Will report back over next week or two how everything goes.

Thanks again all, so helpful!
 

Attachments