Where is internal bypass on RayPak 406a?

[pgershon]

I have found and changed my sensor and unitherm governor. But I'd like to inspect the internal bypass too - not sure what is causing my high limit 2 errors but everything I read points to the bypass as a potential cause. But how do I find and access / remove the bypass. I could not find a clear diagram or video online. I feel stupid.

 

[ajw22]

The internal bypass is on the side of the header. See part 12-HP on page 49 of https://patiopoolsaz.com/wp-content/uploads/2017/09/Raypak406AHeater.pdf

It look like…

016194F - Bypass Valve Kit 105A-405A and 206A-406A - Raypak

This is a replacement Raypak Bypass Valve Kit with Spring for Metal Heat Exchanger.Fits Raypak Models: 206A, 266A, 336A, and 406A Versa Atmospheric Pool Heaters. Also fits models 105A and 405A pool heaters.

www.poolweb.com

 

[pgershon]

I had the 406a open today on the side and I did not see the bypass. I opened the unitherm governor plug and took out the unitherm governor. Do you have to remove the Inlet/Outlet Header to access it? I feel like I must be dense and its right in front, but I just don't understand from the diagram.

 

[ajw22]

Raypak heaters have bronze header, cast iron headers, or polymer headers. You need to figure out what you have. See pages 46-47 in https://s3.amazonaws.com/AWSProd/sites/raypakcom/documents/241236.pdf

Look at where parts 11-HM or 10-HP are on the side of the header.

Post pics of the front and sides of your header.

 

[pgershon]

See photos. Is the bypass under the plug with a large square opening in the outlet next to the unitherm governor? I am not sure what tool to use to open without mangling the polymer?

 

[ajw22]

I think you may have to remove the header to access the Bypass. Let's see if @JamesW has put his hands on one.

 

[JamesW]

I think that you will probably need to remove the header to replace the bypass valve.

If you undo the unions and the unitherm governor plug, you should be able to inspect the bypass valve to see if it looks ok or if it seems to be damaged or defective.

 

[wireform]

For the bypass the header needs to come off.

 

[pgershon]

Do I need to disconnect everything from the header before removing, or can I simply unscrew the cover with all piping etc attached?

 

[wireform]

Piping unions need to be opened and remove the pipe at the next closest point. You basically need clearance with no hindrance so can you properly do the work. I'd recommend before you go into it get all the consumables such as gaskets and orings. Once you touch it after it has been there some time there's no way you'll close it up leak free. Been there done that since then it's change all seals then when you're done you are finished.

 

[JamesW]

Try to see if you can look into the ports to see if the bypass looks ok or if it looks bad before you take it all apart.

What speed are you running the pump?

Can you show the whole system?

What is the filter pressure?

 

[wireform]

I recently did a mastertemp. The bypass breaks apart and you'll need to look further down the line for them. Have seen them get stuck in a check valve or even have see them get stuck at the flow switch in a pentair swcg.

 

[pgershon]

Pump is a single speed 1.5 hp which is horribly overkill for a 3000 sf spa. And I just replaced a burned out pump last year - should have bought a variable speed or two speed replacement. Filter pressure with new filter is about 17 PSI. I'll show some photos. I ordered a new hi limit sensor and a new bypass as a back-up. I took apart the temperature sensor last night and replaced the plastic fitting it sits in. I had replaced it earlier this summer but needed epoxy to seal it as I did not have the plastic part (never opening things up without parts again), I inspected the unitherm governor too and it looked OK, There were a few pine needles stuck in it (which I removed) and the gasket was a bit rough - but I lubed it well and it seemed fine. I did remove some excess epoxy when I changed the temperature probe. Had hoped the would have fixed problem, but to no avail. Its the same every day now: water heats from mid-80s to 103-105 (setting is 107) then trips the high limit. It says "press mode to reset" which I do - essentially turning the heater from off and back to spa. It then sparks and heats water to 107. Just one hi limit 2 trip per day, and it seems like it happens just before the setting high point.

Photos show the spa next to the pool, the spa pump and filter, the 400 but raypak heater and the SWG. Last photo are the spa jets and aerator (2-2 hp super pumps, each controlling 4 jets).

 

[pgershon]

Finally changed bypass. The tip of the spring had gotten rusted stuck to the tip of the bypass pole. I assume spring could not function. Will see how new one does. I installed a new o ring while I was at it. Old one looked ok but better safe than sorry

 

[IvanZ]

Finally changed bypass. The tip of the spring had gotten rusted stuck to the tip of the bypass pole. I assume spring could not function. Will see how new one does. I installed a new o ring while I was at it. Old one looked ok but better safe than sorry

Hello! Did this work for you? Did you have to remove the header to access the bypass? Please let me know. Thanks.

 

[pgershon]

I did have to remove the header and I replaced the gasket in the header to be safe too. Problem has not gone away however. My current thinking is that the area of the heater below the shield and above the bypass sensors gets too hot - especially on hot days. When I remove the outer cover on the heater opening up the zone to better ventilation, I never get the high limit. Others have been successful insulating but I have not.

 

[IvanZ]

I did have to remove the header and I replaced the gasket in the header to be safe too. Problem has not gone away however. My current thinking is that the area of the heater below the shield and above the bypass sensors gets too hot - especially on hot days. When I remove the outer cover on the heater opening up the zone to better ventilation, I never get the high limit. Others have been successful insulating but I have not.

Thanks for the prompt response. It stinks that you still have the problem. I get the code after running it for about 15-20 minutes. Not sure where to start to find a fix. What exactly did you insulate?

 

[pgershon]

From everything I have read, the main causes of high limit 2 errors are reduced or restricted water flow, which can be from your pump or filter, the unitherm governor and the internal bypass. If you are getting the error that quickly, your problem sounds different than mine. If you do not have proper circulation of water, then the water being measured by the sensors may get too hot very quickly without being pumped through. The UG is easy to replace. The bypass takes 20 minutes or so, but is still as easy fix. Also check your filter pressure first.

My issue seems to occur right when the water is about to hit maximum temperature, and it seems to only happen on hot days. I am speculating that the exhaust air (very hot) is getting into the sensor area and causing the sensor to think the water below is over 135 (when it is only 104 ish). The real hot weather my end today so Im interested to see if the problem continues.

Check this thread too...

New Raypak LP heater issue. high limit fault

Just installed my new heater. It keeps tripping the high limit 2 switch. I think it’s a 135 degree trip. I put a thermocouple on that switch and noticed that if the side cover is off, it runs 120 - 128 degrees. If I put the cover back on it runs 127 - 137 degrees and trips. Why would it run...

www.troublefreepool.com

And this one...

Raypak - High 2 limit fault - checked unitherm governor, now what?

Today I changed the internal bypass too. No high limit errors today but we will see if this is a final fix. The old bypass had rusted and the spring looked stuck (see photo). I have now: 1) replaced both high limit sensors and added thermal paste 2) replaced unitherm governor 3) replaced...

www.troublefreepool.com

 

[IvanZ]

Thanks for the prompt response. It stinks that you still have the problem. I get the code after running it for about 15-20 minutes. Not sure where to start to find a fix. What exactly did you insulate?

From everything I have read, the main causes of high limit 2 errors are reduced or restricted water flow, which can be from your pump or filter, the unitherm governor and the internal bypass. If you are getting the error that quickly, your problem sounds different than mine. If you do not have proper circulation of water, then the water being measured by the sensors may get too hot very quickly without being pumped through. The UG is easy to replace. The bypass takes 20 minutes or so, but is still as easy fix. Also check your filter pressure first.

My issue seems to occur right when the water is about to hit maximum temperature, and it seems to only happen on hot days. I am speculating that the exhaust air (very hot) is getting into the sensor area and causing the sensor to think the water below is over 135 (when it is only 104 ish). The real hot weather my end today so Im interested to see if the problem continues.

Check this thread too...

New Raypak LP heater issue. high limit fault

Just installed my new heater. It keeps tripping the high limit 2 switch. I think it’s a 135 degree trip. I put a thermocouple on that switch and noticed that if the side cover is off, it runs 120 - 128 degrees. If I put the cover back on it runs 127 - 137 degrees and trips. Why would it run...

www.troublefreepool.com

And this one...

Raypak - High 2 limit fault - checked unitherm governor, now what?

Today I changed the internal bypass too. No high limit errors today but we will see if this is a final fix. The old bypass had rusted and the spring looked stuck (see photo). I have now: 1) replaced both high limit sensors and added thermal paste 2) replaced unitherm governor 3) replaced...

www.troublefreepool.com

Thanks for the info. I am going to open it up this weekend and give it a good clean, and see if there are any parts that look like they should be replaced.
I hope you can fix it soon.