Raypak 406A Flame w/o CFH

[KBB_TX2]

A very weird problem with the Raypak 007864F igniter in my Raypak 406A spa heater has arisen; I'm wondering if anybody else has seen it. The control board always reports "Flame w/o CFH" even with the bare igniter entirely removed from the heater & pilot assembly and grounded only at the small metal bracket mounted on the insulator. If the wire to the igniter is unplugged at the board, the board does not report any error. This phenomenon is 100% reproducible.

Both the +- 1V/uA on-board readout and a direct measurement in series to the igniter indicates ~0.8 uA DC current with about ~22 VAC being applied. It is clear that something is acting as a diode within the insulator - probing over the surface of the insulator with the ground lead does not result in any current. Ideally, with the igniter removed & cold there should always only be 0 uA. Bypassing the blue HV wire by connecting to the flame end wire gives the same DC current.. It is quite clear that the rectification cannot be any artifact of the PC board.

While replacing the igniter is the obvious next move, has anyone else ever seen rectification through a 007864F insulator?

 

[ajw22]

@swamprat69 @ps0303 @1poolman1 may have some thoughts.

 

[1poolman1]

A very weird problem with the Raypak 007864F igniter in my Raypak 406A spa heater has arisen; I'm wondering if anybody else has seen it. The control board always reports "Flame w/o CFH" even with the bare igniter entirely removed from the heater & pilot assembly and grounded only at the small metal bracket mounted on the insulator. If the wire to the igniter is unplugged at the board, the board does not report any error. This phenomenon is 100% reproducible.

Both the +- 1V/uA on-board readout and a direct measurement in series to the igniter indicates ~0.8 uA DC current with about ~22 VAC being applied. It is clear that something is acting as a diode within the insulator - probing over the surface of the insulator with the ground lead does not result in any current. Ideally, with the igniter removed & cold there should always only be 0 uA. Bypassing the blue HV wire by connecting to the flame end wire gives the same DC current.. It is quite clear that the rectification cannot be any artifact of the PC board.

While replacing the igniter is the obvious next move, has anyone else ever seen rectification through a 007864F insulator?

You may have already looked, but more and more there are reports of insects (saw a praying mantis)/lizards (seen two of those)/frogs getting on the front side of the board, display side facing the bezel, and causing different issues. Might be worth looking.

 

[swamprat69]

The metal mounting bracket on the spark ignitor serves no function other than mounting placement of the spark ignitor. It makes no difference whether or not it is actually grounded. In the sequence of operation, the circuit board will check for for " flame rectification ( flame present)" before allowing the ignitor to spark and the gas valve to be powered. If everything in that circuit is properly insulated and there is an " air gap" between the spark ignitor electrode and case ground you should get no uA reading when this check is made. I would check the electrode circuit for a possible poor connection to ground that would show as a "flame present with no call for heat".

 

[JamesW]

Is this the same heater from before?

Maybe the heater is just getting too old at 16 years old?

What is the flame strength number?

Do you have pictures of everything?

What happened to your old account?

I have a Raypak P-R 406A-EP-C pool/spa heater running propane; it's about 15 years old. It has a 013464F controller board that replaced the original when the latter failed in 2015.

That controller board now behaving very oddly. In SPA (local) mode, it seems to run fine. In REMOTE mode it only heats until it reaches the SPA temperature setting, disregarding what the remote says to do. The SPA max temp is set to 104F, the default. By default the SPA mode set temp. is 65F and despite the signals from the remote computer it won't try to heat; if set to 80F for SPA mode it does heat in REMOTE mode, but only to 80F, ignoring the remote call for heat.

I have reset the board to Factory Settings several times and reseated the connections. The power supply is at 26.9VDC and the flame strength is 8 Good. Has anyone else seen this failure and found a fix other than replacing the board again?

Odd Raypak 406A heater controller issues

I have a Raypak P-R 406A-EP-C pool/spa heater running propane; it's about 15 years old. It has a 013464F controller board that replaced the original when the latter failed in 2015. That controller board now behaving very oddly. In SPA (local) mode, it seems to run fine. In REMOTE mode it...

www.troublefreepool.com

 

[KBB_TX2]

The metal mounting bracket on the spark ignitor serves no function other than mounting placement of the spark ignitor. It makes no difference whether or not it is actually grounded. In the sequence of operation, the circuit board will check for for " flame rectification ( flame present)" before allowing the ignitor to spark and the gas valve to be powered. If everything in that circuit is properly insulated and there is an " air gap" between the spark ignitor electrode and case ground you should get no uA reading when this check is made. I would check the electrode circuit for a possible poor connection to ground that would show as a "flame present with no call for heat".

Thanks for your replies. It is the same heater, but having just been laid off due to sudden large NASA budget cuts to space radiation research, I'm trying to squeeze a little more life out of it while I look for another job.

With the whole igniter entirely removed from the heater, if the little metal bracket on the Raypak 007864F is grounded, I see the rectified current; if not, I don't see it - that's the weird part. A very careful examination shows nothing odd; certainly nothing large enough to see with the naked eye @ 2". Washing it in acetone provided no improvement.

I'll next try heating the 007864F with a torch; if that fails to fix it, I'll apply up to 120 VAC and see if I can break whatever rectifier has formed in it. I haven't yet found a way to replace the metal bracket on the 007864F with an insulator that will take the heat.

I've worked with very high voltage (>70KV DC) over many years and have seen many insulators fail and/or explode, but I've never seen one turn into a rectifier before, which is why I posted the question. Thanks again.

 

[JamesW]

What is the flame strength number?

 

[KBB_TX2]

Just minutes before this problem appeared, when the pilot was running flame strength showed 8 (good). Intermittently, though, the pilot & main would turn off and flame strength would say 0 - those occur so close in time I can't tell whether the board lost rectified current 1st and then shut off the gas, or whether the flame went out 1st. Since the "Flame w/o CFH" appeared, the system won't try to light up with 007864F connected; w/o it being connected, the system will try to spark. I'll try to take some pictures of my test setup on my workbench later today. Thanks again!

 

[JamesW]

When it shows "Flame w/o CFH" can you check the flame strength?

It must be getting some amount of amperage if it is reporting a flame detection.

 

[KBB_TX2]

Thanks again J. You're quite right - if there's a "Flame w/o CFH" message there should be a current and there is.

With the igniter connected to the board, my red DMM reads 0.8 uA while the board is reporting "Flame w/o CFH"; so the board is
behaving perfectly, doing what it should. With the igniter disconnected from the board, the board reports no errors - reconnect it and the error reappears.

I then removed the whole pilot assembly entirely, took it apart, and took photos while testing it out of the heater.

I've just been testing the bare 007864F igniter with a variable voltage AC supply (essentially a light dimmer) on my workbench;
the DC current increases with applied voltage from 27 - 120 VAC. The current increased to about ~14 uADC when I heated the
igniter to ~250F with a heat gun. Both effects are quite reproducible.

In the photo, the yellow DMM is reading VAC across the insulator (I know it's inaccurate), the red DMM is reading
uADC. I verified several times that reversing the red DMM's leads reverses the current's sign. If the lead to the metal bracket
on the 007864F is removed, current is 0.0 uA.

The 007864F's blue wire appeared slightly damaged, so I put green electrical tape on that section to see if it made any difference;
it didn't.

There's something unusual & interesting going on in that little area of the insulator underneath the metal bracket. The physics of
this weird rectification is probably not of interest to the broader pool community except as a source of vexation since this is not
covered in any troubleshooting guide I've found for any similar ignition system. The insulation appears to not be breaking down, as the
spark jumped the ~0.7" gap just fine and appeared normal.

Similar rare events sometimes are reported; I've read of dental work acting as a AM radio receiver, for example. I personally
once saw a false flame rectification occur in a Honeywell module in a home furnace back in the 1980s; it nearly blew up my house,
and appeared to be due to a bit of mold that formed on the PC board. I wrote Honeywell, but they said it only affected modules built
in a particular year.

Back in 2015 I saw this same thing happen in this same 406A; cleaning the wiring & igniter w/ WD40 fixed it and the problem disappeared until 2022. At the time I was curious and so contacted Raypak's tech support to ask if they had ever encountered this issue, stressing that the issue had disappeared after cleaning. Their response was quite nasty & entirely unhelpful - the worst tech
support I'd ever encountered for any product. Paraphrased, it was essentially "You're an idiot! Turn off the gas! Pay our techs!"

Thanks again for all your kind help; I'll fix it one way or another since I know where the issue is. 007864F appears to be N/A,
but I think the whole assembly is still available.

 

[JamesW]

Those meters look like cheap low quality models.

When measuring microamps, you really need good "True RMS" meters.

I've worked with very high voltage (>70KV DC) over many years

I'm surprised that you don't have really good test equipment if you work in electronics.

 

[KBB_TX2]

One uses the tools one has at hand. I'm well aware of the limitations of the tools I use, whether it's a $10 DMM or a $500M linear particle accelerator; in this case a $800 DMM wouldn't serve any better. I once taught an undergraduate course that covered that issue.

At NASA I had better equipment, but before my layoff I tested these cheap DMMs against a NASA officially-calibrated Fluke meter and that showed that these cheap DMMs are surprisingly accurate - usually a few %. Their biggest drawback is that they break very easily.

Any VAC reading on any meter would be distorted by the large inductive transformer load I had connected to the SCRs; abrupt switching gives quite non-sinisodial components. Besides, RMS is not the quantity of interest for a highly nonlinear system like this one.

Anyway, the exact values are totally unimportant here - the Raypak board certainly doesn't use nor care about RMS, just DC, so I presume the board has some DC filtering in it before its ADC, but the exact nature of it isn't important either. The rectified current I measured agreed with the board's 1V/uA test point, and that's plenty close enough for troubleshooting.

If you have schematics the internals of those Raypak boards please post them - a lot of people have had trouble with these boards. My current board replaced one that blew an input buffer & always said CFH even if the inputs were disconnected; cost me $500 in propane in addition to the new board. Note that the boards changed design somewhat over time and their internal parts do not all interchange, although the whole boards do interchange.

I stripped an old igniter out of dead barbecue and am trying that out as a replacement for the 007864F; I hope to have time to test it tomorrow. It ought to fix the weird rectification issue so I can move onto the 406A's other problems.

Thanks for your inputs; this was just a very rare weird issue.

 

[JamesW]

Ok, the heater is really old and it is picking up a stray current from somewhere or the meter in the heater that measures current is bad.

With current in the millionths of an amp range, it requires very accurate measurement.

The flame rectification is based on an AC signal traveling through the flame using ions in the flame to carry the current.

The current flows mostly one way, which creates a pulsed dc current.

Heater Flame Sensing - Further Reading

www.troublefreepool.com

 

[KBB_TX2]

It was fairly easy to modify an igniter from my old broken Craftsman propane barbecue to replace the 007864F for my 406A; now the PC board gives no error messages.

The other issue, where the main burners would sometimes cut off at random times when heating, then immediately relight after the board detected the loss of flame, appears fixed too.

Apparently, minor corrosion on 0.187" spade connectors right at the main gas valve's main connection was the culprit.
Wiggling wires identified an intermittent connection on the (bottom most) pin for the main jets. The connectors are snug and have a minimal coating of special conductive welding grease (from Eastwood) to prevent further problems.

Again, thank you again to all for your assistance. Documenting these problems helps us all.

 

[7rdr7]

A very weird problem with the Raypak 007864F igniter in my Raypak 406A spa heater has arisen; I'm wondering if anybody else has seen it. The control board always reports "Flame w/o CFH" even with the bare igniter entirely removed from the heater & pilot assembly and grounded only at the small metal bracket mounted on the insulator. If the wire to the igniter is unplugged at the board, the board does not report any error. This phenomenon is 100% reproducible.

Both the +- 1V/uA on-board readout and a direct measurement in series to the igniter indicates ~0.8 uA DC current with about ~22 VAC being applied. It is clear that something is acting as a diode within the insulator - probing over the surface of the insulator with the ground lead does not result in any current. Ideally, with the igniter removed & cold there should always only be 0 uA. Bypassing the blue HV wire by connecting to the flame end wire gives the same DC current.. It is quite clear that the rectification cannot be any artifact of the PC board.

While replacing the igniter is the obvious next move, has anyone else ever seen rectification through a 007864F insulator?

I had the same issue. Followed the Raypak troubleshooting guide and it pointed to a gas valve. Replaced the gas valve and all is good.