Raypak 336A-EN Nat gas heater flame rollout

[caycarem]

Could use some help from the heater experts on this issue.
Any idea what is causing flame rollout issue with my recently installed used Raypak R-336A natural gas heater? Seems to be burning below the burners and then roll out to front. I removed top layers until the exchanger and cleaned a pile of dead leaves and now less flame out but still there and won’t stay on. I also cleaned the burner tubes woth a coat hanger wire and they weren’t clogged.

Videos taken after vacuumed.
should I remove gas like and pull out the burner tray to take a look for what is possibly still blocking gas mix from going up and out the top?

i also tried to peek through the burners from bottom and saw something like a layer of white ceramic in the middle of the heater above the burners and below the heat exchanger. What does this do?

Raypak 1
Raypak vid 2

 

[ajw22]

See if this thread is helpful...

Raypak Heater problem (flame rollout)

I have a raypak p-r406a-en-c (natural gas) unit and I'm having a flame rollout problem. I looked at the flue and it's clear. There's no obvious issues (no dead beasties). No obvious damage. I tried adjusting the pressure a bit, 3/4 of a turn counter clockwise didn't change the flame height...

www.troublefreepool.com

Google search results

www.troublefreepool.com

 

[caycarem]

See if this thread is helpful...

Raypak Heater problem (flame rollout)

I have a raypak p-r406a-en-c (natural gas) unit and I'm having a flame rollout problem. I looked at the flue and it's clear. There's no obvious issues (no dead beasties). No obvious damage. I tried adjusting the pressure a bit, 3/4 of a turn counter clockwise didn't change the flame height...

www.troublefreepool.com

Google search results

www.troublefreepool.com

Thanks I’ve read just about every threads on this including this one. Does not seem any spiderweb clogging the burners as I’ve poke through all of them. Wanted to see if anyone can tell what the issue might be by looking at the videos before I attempt to remove the burners and dealIng with reconnecting gas pipes and valve.

 

[ajw22]

Let’s see if @Pool Clown @swamprat69 @1poolman1 are around.

 

[Futuresvt]

Have you tested the gas pressure before and after the manifold regulator?
I don’t recall anything being in between the burners and heat exchanger unless part of the ceramic sidewall has fallen.

 

[swamprat69]

There should be nothing blocking the path of combustion byproducts between the burners and the bottom of the heat exchanger. Yellow flame above the burners is indicative of inadequate combustion air (various causes). Blue flame below the burners may indicate more combustion air is available from the outside after the flame starts to roll out. There should be a pipe union to the left of the gas valve. If it is inside the cabinet it should be easy, you just need to open it to remove burner Rear'y after marking and removing wiring from the burner Rear'y/ gas valve. If it is outside the cabinet, you will need to open the union ( always use 2 wrenches ) and remove the long pipe nipple from the gas valve. If the underside of the heat exchanger is blocked/plugged by a white powdery substance (silica) that is easily removed by a wire brush it would indicate excessive contamination of combustion air into the burner box. Rollout is generally indicative of a blockage to the flow of combustion byproducts, so you have to make sure that you have no blockages first. After removing the burner Rear'y, you can put a light source in the burner box and inpect the heat exchanger from above to make sure it is clear. Any gas piping/fittings that you open must be resealed correctly and checked for leakage before firing up the heater again. Wider field of view shots of the heater with the door off would be helpful. Exactly how old is the heater (recently installed)? If you have the burner Rear'y pulled out , you should check that the burner slots are clean and clear and also check the gas orifices on the gas manifold to insure that they are also clear. If no blockages are found, can go on further from that point.

 

[caycarem]

Have you tested the gas pressure before and after the manifold regulator?
I don’t recall anything being in between the burners and heat exchanger unless part of the ceramic sidewall has fallen.

Don’t know how to test this but last heater was a 400k btu Laars and it worked fine.

swamprat - thank you so much for your analysis and your guide on how to remove the gas hookup is just what I imagined. I added pics of the heater, based on serial # it is a 2008 model although the pool guy assured me it was working and only 3-4 years old. The burner pics were taking from bottom in iphone selfie mode and as you can see there’s a white ceramic rectangle plate just above the burners. The left corner of plate also has a large broken hole maybe this causes more air in the burning chamber? I’m stumped why the plate is there to begin with, blocking the middle.

 

[caycarem]

There should be nothing blocking the path of combustion byproducts between the burners and the bottom of the heat exchanger. Yellow flame above the burners is indicative of inadequate combustion air (various causes). Blue flame below the burners may indicate more combustion air is available from the outside after the flame starts to roll out. There should be a pipe union to the left of the gas valve. If it is inside the cabinet it should be easy, you just need to open it to remove burner Rear'y after marking and removing wiring from the burner Rear'y/ gas valve. If it is outside the cabinet, you will need to open the union ( always use 2 wrenches ) and remove the long pipe nipple from the gas valve. If the underside of the heat exchanger is blocked/plugged by a white powdery substance (silica) that is easily removed by a wire brush it would indicate excessive contamination of combustion air into the burner box. Rollout is generally indicative of a blockage to the flow of combustion byproducts, so you have to make sure that you have no blockages first. After removing the burner Rear'y, you can put a light source in the burner box and inpect the heat exchanger from above to make sure it is clear. Any gas piping/fittings that you open must be resealed correctly and checked for leakage before firing up the heater again. Wider field of view shots of the heater with the door off would be helpful. Exactly how old is the heater (recently installed)? If you have the burner Rear'y pulled out , you should check that the burner slots are clean and clear and also check the gas orifices on the gas manifold to insure that they are also clear. If no blockages are found, can go on further from that point.

The ceramic plate seems to fit nicely in the middle it’s hard to imagine it’d be a wall that fell. But then I also couldn’t identify any such part from the parts diagram.

 

[caycarem]

Update: you’re right on, I reopened the top, indeed the front ceramic wall broke off and fell into the middle of the gas chamber. What a bummer! Not sure if it’s worth replacing this $200ish piece or how to do it.

 

[swamprat69]

From the photos I am not sure how the vertical piece that seems to be above the burners but below the heat exchanger is attached. It looks like it splits the burners into right and left sides. The piece that has the broken corner looks to be below the burners. The piece that is broken in half from the front might just drop into place if it wasn't broken. You might try to see if the matching rear piece easily lifts out from its position. Did you find the missing half that cracked off of that piece somewhere inside? I am not sure what would have caused that piece to break. You should try contacting RayPak and sending them your photos questioning what could cause this.

 

[caycarem]

That piece on top of the exchanger was the remaining top 1/3 of the front wall which I pulled up and placed it there. The bottom 2/3 broke and dropped on top of the burners. These are raypak refractory front and back part #010092F based on the manual for R336A. My guess is it became brittle and broke off when it got moved.

the far end wall also looks cracked. I’m now deciding whether to buy replacement parts or another heater.

thank you for your help.