406A raypak heat shuts off after 5 minutses and keeps cycling

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brendanmcaninch

Active member
Jul 6, 2020
26
orinda ca
I have a 406A399k BTU natural gas heater. I have replaced high limit switches, pilot assembly and have a good circuit board. (new)
I turn on the heater it works for about 5 minutes then cycles. the gas shuts off, no error and then it sparks and reignites for about 1 minute or less then continues that cycle.
I have had everything cleaned out. I have cleaned my ground wire. I am stumped. I did have a rodent chew one of the high limit wires but i taped it up- and get no high limit error.
Could this by a bypass switch or a pressure switch problem? Or any suggestions?
 
Adding a little more here. I took a wire brush and cleaned the pilot assembly- the walls of as was some rust in there. The heater fired and worked for 45 minutes- got the spa up to 101 and then it started cycling again. I think maybe it is the grounding now but not sure why it would stop after 45 minutes now. Anybody have any ideas- or just go do some more cleaning? Thanks
 
Thank you. I went through the fault history and have all Main Ingitition Failures and the 3rd one was No pilot sensed. all the rest1-10 were main ignition failures. Could insulating the High LImit switches help that? I would think it would give me an HLS fault. Do you know where i can get that type of insulation or what it is called? I am a novice but in the 406A manual it says on trouble shooting Under "Heater going off and on continuously" that could be External Bypass setting is out of adjutment ( solution adjust bypass) and also "Pressure switch out of adjustment... (solution adjust pressure switch). Are those things difficult to do and or do you think these could be the problem? I really appreciate your help!
 
brendanmcaninch said:
I went through the fault history and have all Main Ingitition Failures and the 3rd one was No pilot sensed.
Click to expand...

Then you likely have a flame rectification sense problem or your heat exchange is leaking and drowning the flame.

Could be a loose ground, bad high tension wire, sooted pilot, loose pilot, Check to make sure that the ground down by the pilot assembly is OK.

Check there is no corrosion around the pilot assembly.

Raypak 406A Burner won't fire but do get pilot

Burner won't fire... Corrective action taken: All safety switches operate, I disconnected them and jumpered the wires getting an error when open and no error when jumped roll over switch works, error when open, no error when jumped or connected. Spark at pilot and it lights fuse on main board...
www.troublefreepool.com www.troublefreepool.com

Here is the manual for your heater: http://cdn.globalimageserver.com/FetchDocument.aspx?ID=c404f1c5-ac50-4209-9457-56246d010b20. Look at page 34. If you do not have a millivolt system look at the bottom pilot assy. . Start cleaning by turning off heater and and gas supply shut off. Remove pilot bracket screw and green ground wire at bottom right of burner manifold bracket. Remove pilot tubing at gas valve. Remove pilot assy. and pilot tubing as one piece. Clean all metal pieces where pilot assy. bracket was attached to the burner manifold bracket including the screw and the metal termination of the green wire with a small stainless steel wire brush and/or small diamond file (available at Harbor Freight). On the pilot assy itself (page 34) you need to clean the underside of the pilot hood (above the pilot tubing attachment) with a dental pick (Harbor Freight) until the metal is clean. Also gently clean the spark rod with a small diamond file or steel wool all the way around to get bare metal, being careful to support the ceramic insulator so that it doesn't crack. Clean the underside of the ground hood ( opposite the pilot hood with the 2 extended tabs on the outside edges) with small stainless brush and/or diamond file to get to bare metal. Clean any screws and metal points of attachment at the grounding hood side of the pilot assy. at the pilot bracket and burner frame that the pilot bracket is attached to. Reassemble in reverse order making sure to tighten the pilot tubing to the gas valve. Turn on gas shut off and power to heater. Put a small amount of dawn dish detergent mixed with a little water on the pilot tubing attachment at the gas valve. Fire up heater. Check for any bubbles at pilot tubing attachment at gas valve (indication of a leak).

What does the Flame Strength indicator show on the Service Menu?

Service Menu and Fault History
To access the Service Menu and fault history, press the MODE and UP buttons simultaneously for 3 to 5 seconds. The heater will continue to operate normally while in the Service Menu. The first screen displayed is the Flame Strength indicator, which indicates the pilot flame current using a bar graph and numerical display. A signal of less than 4 indicates a weak flame signal and may require service. Refer to Section 5 Troubleshooting in the manual for possible causes and corrections.

Press the DOWN button. The Supply Voltage screen indicates the voltage supplied to the control board. Normal readings range from 24 to 29 volts.

Press the DOWN button. The Run Time indicates the total hours of operation for the pool heater, as measured by the amount of time that the main gas valve has been powered. The Cycle count indicates the number of on/off cycles of the heater, as measured by the number of times the pilot valve has been powered.

Press the DOWN button. The Fault History can display up to ten faults in memory. The order of the faults begins with “Fault Last,” which is the most recent fault, and proceeds through ten most recent messages in chronological order. The second line of the display shows the fault message. If there are no faults in the history buffer, the second line reads “All Faults Clear.”
brendanmcaninch said:
I am a novice but in the 406A manual it says on trouble shooting Under "Heater going off and on continuously" that could be External Bypass setting is out of adjutment ( solution adjust bypass) and also "Pressure switch out of adjustment... (solution adjust pressure switch). Are those things difficult to do and or do you think these could be the problem?
Click to expand...

No, those are not likely to be the problem
 
So my Flame when on is 8. earlier today i did scrub with wire brush the mounting bracket as well as the fork on the pilot. I didn't remove the tube and take it out I left it in the heater and worked around it. I also cut the green ground wire to stripped to fresh wire and screwed that direct into the grounding screw. This seemed to help for a while- heater ran 45 minutes before it started to cycle- temp up to 101. So i thought was a grounding issue. The pilot is fairly new- 2 years and looks to be in good shape.
 
Corrosion in the grounds can cause a loss of the millavolt flame sense signal that needs to flow through the grounds.

Confirm what the Fault History is now showing for the cycling as I think it may be a different unrelated problem.

Let's have @swamprat69 take a look if he passes by.
 
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brendanmcaninch said:
My flames look high and yellow more than blue.
Click to expand...
Blue flame for NG is good. Yellow flame is not.

A yellow or orange flame means that too much gas and/or not enough oxygen is being used when burning. Another symptom is a black, sooty residue, as the gas does not burn cleanly.

In your cleaning I hope you did not enlarge the gas orifices.
 
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Yellow is an indication of insufficient air to support a solid blue flame. It also produces both soot and carbon monoxide. Most probable cause is dirt/corrosion in the pilot orifice and or burners (depends on which flame is yellow). A thorough cleaning by a qualified service tech would be recommended as the heat exchanger may also be sooted up depending on how long the yellow flame situation has existed. Heater should not be run as is because the problem will only compound itself and is not safe.
 

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ajw22 said:
Corrosion in the grounds can cause a loss of the millavolt flame sense signal that needs o flow through the grounds.

Confirm what the Fault History is now showing for the cycling as I think it may be a different unrelated problem.

Let's have @swamprat69 take a look if he passes by.
Click to expand...

swamprat69 said:
Yellow is an indication of insufficient air to support a solid blue flame. It also produces both soot and carbon monoxide. Most probable cause is dirt/corrosion in the pilot orifice and or burners (depends on which flame is yellow). A thorough cleaning by a qualified service tech would be recommended as the heat exchanger may also be sooted up depending on how long the yellow flame situation has existed. Heater should not be run as is because the problem will only compound itself and is not safe.
Click to expand...
In late 2020 I had my technician pull out the burner tray and clean the burners. After that is when these various problems started on the cycling and overheating i guess. Yesterday after cleaning the pilot assembly that seemed to work but I had my cover open- so cool air and oxygen were getting in- and got it heated without a fault to 102. But today i closed it to see if that would work- and it got to 84 degrees and then got the Main Ingition Failure fault. I have attached a couple of pictures but the flames seem maybe too strong. I went through and did the flame strength which read 8- but it seems to be higher around the pilot side. It could be when the technichian cleaned it he made the holes bigger then- because was a lot more flame after his cleaning. I have not really used it much since then as kept having problems with it. Is there a way to turn the gas pressure down would that be a possible fix and if so what is the best way for a novice to do it? Thank you all so much.
 

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I think @swamprat69 is going to say that it is time for a qualified service tech to go through your heater.
 
Finding a qualified service technician for a pool heater is not always easy. Many HVAC companies do not want to work on them because they are not familiar with them and many of the parts are not available at HVAC parts suppliers. Not all pool service technicians are familiar with heating service. Many only know of common problems that are specific to pool heaters ( similar to the fact that all HVAC technicians do not have the same level of knowledge). I am not saying that there aren't any top notch pool heater technicians out there, only that it is a Crud shoot finding them. You do need a qualified service technician to clean and inspect your heater to make sure all problems are resolved and nothing is overlooked.
 
A pool heater is basically an open loop boiler (no expansion tank) and this type of system has been used in the past (I am dating myself here) where an open tank similar to a toilet tank was placed at the highest point in the system to absorb the differing volumes of water ( a noncompressible) as the system heated and cooled. Your pool acts as the open tank.
 
do Raypak warranty company B and B pools in the bay area. my technician just wants me to buy a new heater from them. maybe the right thing but would like to have someone I know is raypak qualified to look at the heater - any suggestions from anybody. In the east bay San francisco. Thanks again to everyone.
 
Wanted to check one more thing and remove the burner tray and see what the technician has done with them- and if any of the burners look like the need to be replaced. But not sure what is the correct way to disconnect the gas valve. Here are 2 pics- one right on the outside of my heater then inside. I think the one on the outside is the one i am supposed to disconnect but not sure. I have seen and read most of the instructions on how to clean the burner tray. Just a little stumped on the proper way to disconnect it. Thanks
 

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