Rheem / Raypak 406A Gas Pressure Issues - Fixed, Now Will Not Start

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L

lesjonpool

Member
Mar 12, 2024
14
Atlanta, GA
Current State - I cannot get my Rheem 406A with Honeywell gas valve to sustain heating. It heats for about an hour and then the flame strength peters out (starts at 8, runs for a while, then drops off quickly before the unit shuts off - unit then tries to relight but can't). I then have trouble lighting it again. The only faults I get are "No Pilot Sensed" and "Ignition Failure". There are no faults that have to do with cutting off the boiler. The pilot always lights. Sometimes, I need to jiggle the pilot around to get the pool heater started. The unit has 4.25" wc gas pressure before the valve, currently. When the unit runs, gas pressure drops by about 2" wc.

I have consulted this board frequently but cannot seem to solve my problem. I am uncomfortable spending the money to replace the heater because I am unconvinced that a new heater will fire and serve consistently. I would like some help determining this by being able to confidently determine why this pool heater is not firing and that a new one will fire reliably.

Original problem - flame rollout observed at the end of the season in 2022. Replaced the sensors but that did not fix the problem The 18-month saga begins:

Fixes applied:
  1. Rebuilt burner. See photo of burner. Seemed to be low gas flow issue with 5-year old burner that looked like heck.
  2. Had the gas line to our house rebuilt by the gas company. Minor fix to gas piping to pool heater. Plumber ensures that there is plenty of gas to the heater (12" wc?)
  3. Replaced the ignition assembly.
  4. Tested the gas valve to satisfaction by testing and switching them out and observing no improvement.
  5. Replaced the control board.
  6. Had a green licensed boiler tech fail to fix the pool heater but also failed to specifically tell me why I neeeded to replace it.
    1. It appeared as though he was parts changing. For example, I didn't think the control board was the issue but he did it anyway. I was aware of the testing procedure in the manual and his resolution. I had already explored it. It did not fix the problem.
    2. He indicated that the heater needed 12" wc pressure at the unit.
    3. Read in the manual that the unit needed 4" wc and not 12".
    4. The pilot looked like the olympic torch at 12".
  7. I added a gas regulator to get the pressure down to 4" wc per the manual.
  8. Unit started firing more consistently but still intermittent. A couple of times, I heard a pop before the unit shut off. I thought it might be a high temp cutoff so I cleaned the heat exchanger (see #10).
  9. Checked ground and rerouted it to a point with less rusty footing. Connection is tight and terminals are clean.
  10. Cleaned heat exchanger in-situ - it isn't perfect. See attached before and after pictures. Haven't heard the pop before cutoff since.
Any help will be appreciated. I am fine with getting a new heater as long as it will solve the problem.


Thank you!
LJP
 

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  • RheemManual_GasPressure.jpg
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  • RheemPoolHeaterNameplate.jpg
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  • RheemWornBurners_LowRes.jpg
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The inlet pressure is too low.

The heater is in poor condition and not safe to operate.

Time to replace the heater.

Make sure that the heater Inlet pressure is correct for static (Heater not operating) and dynamic (Heater firing).

The proper design pressure drop for the gas line is a maximum of 0.5" w.c.
 
Welcome to TFP.

Given that your heater rusted out in 5 to 6 years I would replace it with a sealed burner heater like the Raypak Avia or Pentair MasterTemp or Hayward H-Series heater. You may get better life from a different heater design.
 
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OK, this is very helpful, thank you everyone. I misread the manual on the 4" wc being the regulator at the valve. 14" wc is correct for the supply. As a quick fix, I adjusted the pressure to 6.5" wc and it is still not firing up.I will adjust to 10.5" wc this evening.

I acknowledge and appreciate that the heater is aged beyond its years and unsafe to run. I would like to get it to sustain operation for some time so I can have confidence that a new water heater will run. To this end, any ideas of why the unit will not light now? I would like to get a read on it while it is running so I can make sure it is between 6 and 10" wc while running. As a summary:
  1. Ran fine, albeit temporarily, yesterday. Multiple times even at 4" wc. I failed to mention that I increased the gas pressure while it was running to see if that would strengthen the flame. I saw some improvement.
  2. No faults except "Main Ignition Failure" and "No Pilot Sensed". Pilot is clearly on.
I remain concerned that I am going to have the same problems with a new heater. I don't want to run into a situation where I have it installed and then the installer point to it not running being the gas company or a plumber's business. I want this done with as few interactions and headaches as possible.


Thank you again
 

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The regulator outside the heater indicates that you probably have 2 psi service to the heater and then the pressure should be a minimum of 6 in. WC and a maximum of 10.5 in. WC upstream under load and no-load conditions for natural gas.

The brass vent might be for indoors only, so you should check that as it might allow water into the regulator.

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Vent limiters are used indoors.

Vent protectors are used outdoors.

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Heater issues? Gas regulator? Troubleshooting?

We have been using our pool (completed in March 2023) all winter in MD with no issues. We have it set to 70 degrees. I got in the pool Saturday to swim and noticed the water seemed colder. I checked the heater and the set point was 70 but the actual temperature of the water was 66. While I was...
www.troublefreepool.com www.troublefreepool.com
 
If you put in a new heater and it does not work I would look at your gas meter.

Do you have other gas appliances in the house?
 
i am only getting 6.5" wc because I installed a second regulator you cannot see. I am going to remove this regulator.

I will replace the vent limiter on the regulator you can see with a protector.

The gas meter was replaced when the gas company rebuilt our line.

I have other gas appliances - 3 water heaters, 3 furnaces, and a fireplace. The line from the street and the meter should be fine. The new equipment accounts for all 8 devices.

I do not have a drip leg in the proper place. I noticed that in the manual that was posted. I also do not have the ideal run of piping before the unit. Unfortunately, i just have to deal with this. Perhaps I can install a drip leg outside the heater but it is tight.
 
lesjonpool said:
Current State - I cannot get my Rheem 406A with Honeywell gas valve to sustain heating. It heats for about an hour and then the flame strength peters out (starts at 8, runs for a while, then drops off quickly before the unit shuts off - unit then tries to relight but can't). I then have trouble lighting it again. The only faults I get are "No Pilot Sensed" and "Ignition Failure". There are no faults that have to do with cutting off the boiler. The pilot always lights. Sometimes, I need to jiggle the pilot around to get the pool heater started. The unit has 4.25" wc gas pressure before the valve, currently. When the unit runs, gas pressure drops by about 2" wc.

I have consulted this board frequently but cannot seem to solve my problem. I am uncomfortable spending the money to replace the heater because I am unconvinced that a new heater will fire and serve consistently. I would like some help determining this by being able to confidently determine why this pool heater is not firing and that a new one will fire reliably.

Original problem - flame rollout observed at the end of the season in 2022. Replaced the sensors but that did not fix the problem The 18-month saga begins:

Fixes applied:
  1. Rebuilt burner. See photo of burner. Seemed to be low gas flow issue with 5-year old burner that looked like heck.
  2. Had the gas line to our house rebuilt by the gas company. Minor fix to gas piping to pool heater. Plumber ensures that there is plenty of gas to the heater (12" wc?)
  3. Replaced the ignition assembly.
  4. Tested the gas valve to satisfaction by testing and switching them out and observing no improvement.
  5. Replaced the control board.
  6. Had a greenlicensed boiler tech fail to fix the pool heater but also failed to specifically tell me why I neeeded to replace it.
    1. It appeared as though he was parts changing. For example, I didn't think the control board was the issue but he did it anyway. I was aware of the testing procedure in the manual and his resolution. I had already explored it. It did not fix the problem.
    2. He indicated that the heater needed 12" wc pressure at the unit.
    3. Read in the manual that the unit needed 4" wc and not 12".
    4. The pilot looked like the olympic torch at 12".
  7. I added a gas regulator to get the pressure down to 4" wc per the manual.
  8. Unit started firing more consistently but still intermittent. A couple of times, I heard a pop before the unit shut off. I thought it might be a high temp cutoff so I cleaned the heat exchanger (see #10).
  9. Checked ground and rerouted it to a point with less rusty footing. Connection is tight and terminals are clean.
  10. Cleaned heat exchanger in-situ - it isn't perfect. See attached before and after pictures. Haven't heard the pop before cutoff since.
Any help will be appreciated. I am fine with getting a new heater as long as it will solve the problem.


Thank you!
LJP
Click to expand...
Be very glad this heater doesn't work and dont throw money/time/effort/frustration at it. It is very dangerous to operate.
The refractory material is destroyed. That's what keeps the flame where it belongs.
Those burners are going to continue to produce soot and clog the already damaged heat exchanger.
Is this heater under a roof or tree that allows a lot of water to fall on it?
Is there a tablet feeder after the heater? The damage to the exchanger, the green areas, appear to be a leak. That, too, would account for the destroyed-beyond-recovery burner tray and refractory panels.
 
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