Raypak 406 heater no pilot sensed / ignition lockout

[pgershon]

Pool heater cycles and board says spark many times, but no pilot and it eventually locks out. Had gas company in to service on Friday and Saturday and they replaced a transformer, the gas valve assembly, and broke the main board and had to replace it too. At the end of all of this, I went to fire it up today and the old problem remains. If I remove the cover, I hear a noise when the pilot tries to light, but no pilot comes on. It's like a cranking noise.

Any ideas what might be going on? Heater is 9 years old but they replaced main board and the gas valve assembly. I had a similar problem last year.

 

[swamprat69]

Some possibilities are weak spark due to dirty electrode and/or pilot flame hood. Also possible is weak/low pilot gas pressure due to a dirty pilot orifice. Both can be corrected by disassembly and cleaning or replacing the pilot assembly.

 

[pgershon]

Thanks. A couple of thoughts that might be more helpful to diagnose...

1) The heaters makes a grinding noise when it tries to ignite the pilot. I hear it pretty clearly when I remove the cover. Its like the electrical signal is being sent, but it sounds like it is shorting out.
2) The repair crew that worked on heater replaced the board and the gas valve on Friday/Saturday with no effect. They then spoke to RayPak customer service and were directed to replace a transformer. Unfortunately they broke the main board in the process and had to come back a second day - I was not there when they returned, but they reported the unit repaired - but I have the same issue as when they started. I believe they said they replaced pilot assembly, but I am not certain.
3) This similar problem appeared last spring as well. It was corrected when they installed a new main board. I suspect the issue was and remains something else.

 

[swamprat69]

There is always the possibility of a weak spark from the control board (but not likely with a new board) . I would check to see if the pilot assembly has indeed been replaced. Grinding noise is probably the spark going to ground. Another thing to check would be, Is the spark actually happening at the pilot assembly electrode or is it going to ground at a place other than the pilot assembly due to frayed wiring etc..

 

[pgershon]

So here is what I can say:
1) spark is going to pilot
2) pilot assembly was cleaned and blown but not replaced. It looked OK. And it is sparking
3) Circuit board and transformer and gas valve were replaced. We even swapped the known working circuit board from pool heater next door. Always the same issue
4) Transformer is giving 24V as it should. But gas valve is only getting 16V of power - less when the board from pool heater was used (its a 10 year old old style board vs a new one). Something seems to be causing power loss from board to valve.

Repairman left stumped, I dont know next steps. 10 year old unit. Not in terrible shape otherwise,

 

[swamprat69]

It would be helpful if you filled out your signature information and would also be helpful to know your location. As I understand it the gas utility company was servicing your heater??? Is that correct? I am having a hard time understanding why they are having such a hard time diagnosing why an electronic spark pilot is not lighting? Either the pilot is not getting sufficient gas pressure (dirty pilot orifice or a problem with the gas valve) which the technician should have diagnostic tools (manometer) to check pilot gas pressure out of the gas valve and knowledge to disassemble and check the pilot gas orifice for dirt/blockage or for some reason the spark is not igniting what would be a good/normal pilot flame ( spark should occur between the tip of the electrode and the edge of the pilot hood) which can be hampered by a dirty electrode tip, a dirty pilot hood or a weak spark from the control board or associated wiring. The voltage drop to the gas valve can be caused by a sticking gas valve solenoid or poor contacts on the gas valve relay of the main circuit board or possibly an undersized VA rating of the replacement transformer. Don't let them throw away any of the old parts. It seems like they are just replacing parts in hopes of repairing the heater that way. Since three of the parts associated with the probable cause of the problem are new (excepting the pilot assembly and its orifice) any service and the three parts should be under warranty. Hopefully this problem is not due to a dirty pilot orifice. You may want to ask for a senior service technician and carefully observe and question everything that he does.

 

[swamprat69]

Just a note: Blowing does not necessarily clean out a dirty pilot orifice, it must be disassembled and cleaned because the dirt buildup is on the exit side of the orifice.

 

[pgershon]

After gas technician left, I looked at wiring diagram and thought about what he said and my system. He mentioned that gas valve was not getting 24V... also said they did not look at Jandy and wanted an electrician to do so...

Then I recalled problem really began with spa heater reading fireman switch not open. The small board in the Jandy for the dual pump spa heater (Jandy 6586) has a wire receptacle that had come loose. It acted up last year and was fixed by pressing it in better. I did this to get a "turn on" signal to the heater, which I had (I guess improperly) assumed was binary. I thought "perhaps heater not getting a strong enough signal because of loose wire on board?" Anyway I had a spare 6586 that I sent to service to have that clip re-soldered and installed it. Voila, the spa heater fired up. Gas company never looked at the Jandy side. Going to be a fight to deal with their bill now - new gas value (they claimed old one was worn though it seemed functional) - new board (I dont think they charge because they replaced last year and admit to breaking the old one when they took it out) - new transformer (at least cheap part) - and about 4 hours of labor.

Bottomline however, low power to valve seemed to be cause by bad connection on Jandy 6586 dual heater board.

 

[swamprat69]

Good job of critical thinking! Just remember that your heater should be cleaned/serviced on a regular basis for safety/ longevity. Like the old automobile repair ad that stated " You can pay me now $, or you can pay me later $$$$".

 

[pgershon]

Thanks for your help.

 

[pgershon]

Now that everything is working, I am getting a Hi Limit 2 fault. Unit goes back on but eventually will come up again. A few things to note:

1) The board and gas valve are new replacements from this past week
2) I adjust the spa temperature maximum to 107, overriding the default 104 max. Not sure but this could relate to the fault. The reason I do this is that the temperature probe on the heater tends to be off by about 3-4 degrees. To heat the hot tub to 104 (per Jandy proper and external thermometer) I must set heater to 107. 104 on heater corresponds to 101 at the spa.

Any thoughts? (btw I bought a new temperature probe for heater several years ago but never installed)