Raypak 266a propane: black smoke

70runner

Active member
Jun 27, 2015
39
Fallbrook CA
About 8yrs old, hasn't been run for a couple years. Fired up today and looked like a fireplace chimney. It did heat the water, but slowly. From reading through similar posts, sounds like I need to remove the burner tray, check nozzles, then pressure wash heat exchanger. Does this sound about right? Anything else to look for?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,140
Northern NJ
Did your smoke look like in the pics here?


Black smoke indicates a combustion problem. You need to open the heater and see what you find in the burner area.
 

70runner

Active member
Jun 27, 2015
39
Fallbrook CA
Very similar to pic. Smoke was exiting vents and top of unit. I had previously wire meshed all the larger openings, to rat proof the unit (we live in the middle of an avocado grove), so don't think I have a critter issue. I'll start disassembling tomorrow.
 

70runner

Active member
Jun 27, 2015
39
Fallbrook CA
Pulled the burner tray, cleaned the burner tubes, moderate soot. Nozzles looked OK. Pressure washed the heat exchanger from above and below. Lotsa soot. Put it back together, now the heater cycles. Flame looks good. Checked pressure switch, seems to be operating normally. Suggestions?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,140
Northern NJ
Pulled the burner tray, cleaned the burner tubes, moderate soot. Nozzles looked OK. Pressure washed the heat exchanger from above and below. Lotsa soot. Put it back together, now the heater cycles. Flame looks good. Checked pressure switch, seems to be operating normally. Suggestions?
Is it still smoking or the exhaust clean?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,140
Northern NJ
You should have a blue flame not an orange yellow flame.


I think your propane gas pressure is too high or the orifice needs to be adjusted or you have insufficient airflow to the heater. You need less gas to give a cleaner more complete burn. The excess gas is creating the smoke and soot.

Post a pic of the heater and it's surrounding environment and how the exhaust is vented.

I think you need to call a qualified gas contractor.
 

RDspaguy

In The Industry
Mar 21, 2020
709
Cabool, Mo
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This is probably why it is cycling, but if you powerwashed the heat exchanger without pulling it you could have all kinds of stuff wet and dirty. I always pull it and take it somewhere it won't stain concrete.
How long did you wait to turn it back on?
Try using a blow dryer on low heat and high air to dry all components. See if that clears it up. Plan to be there a while. Do not overheat board, but pay close attention to wire harness connections.
Keep us posted.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,140
Northern NJ
I tried it within an hour or so of pressure washing and didn't pull it. Would that explain the yellow flame?
No, you probably have two different problems:

1 - incorrect air/gas mixture indicated by yellow flame creating smoke and soot

2 - cycling of the heater. If the too hot yellow flame was tripping an over heat safety it should display an error message.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,140
Northern NJ

70runner

Active member
Jun 27, 2015
39
Fallbrook CA
Appreciate you guys giving me a hand with this.

On pg 36 it says yellow flame indicates restricted airflow or incorrect orifice. Airflow is not restricted. Where is this orifice? Is it something supposed to be in the propane supply line?

Also, I've checked the whole manual, can't find anything about a flame sensor. It does address a flame roll-out switch.

No error messages.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
18,140
Northern NJ
What altitude are you at?

This discussion says the Raypak Standard Digital is good to 2,000 feet. Atmospheric heaters: Rated inputs are suitable for up to 2,000 feet elevation. For elevations above 2000 feet, reduce input 4% for each 1,000 feet above sea level, as high elevation reduces combustion performance.


@JamesW thoughts?
 
Last edited:

JamesW

TFP Expert
Mar 2, 2011
19,425
The yellow flame looks really bad.

Yellow flame is the result of incomplete combustion.

Yellow flame is much cooler than blue flame due to insufficient oxygen to allow full combustion.

Yellow flame creates carbon monoxide instead of carbon dioxide (only one oxygen vs two).

The flame should be above the burners, not below.

Possibly a restricted air flow issue.

What is the exact heater model number and age?
 

70runner

Active member
Jun 27, 2015
39
Fallbrook CA
I'm at about 700ft so should be good unless I got the wrong set of orifices. There are 5 part numbers, I assume I have #57? Are they marked? If the orifices are correct and there is unrestricted airflow, then perhaps my propane regulator needs checked/adjusted?
 

70runner

Active member
Jun 27, 2015
39
Fallbrook CA
The yellow flame looks really bad.

Yellow flame is the result of incomplete combustion.

Yellow flame is much cooler than blue flame due to insufficient oxygen to allow full combustion.

Yellow flame creates carbon monoxide instead of carbon dioxide (only one oxygen vs two).

The flame should be above the burners, not below.

Possibly a restricted air flow issue.

What is the exact heater model number and age?
Rheem/Raypak P-266a-EP-C, installed Dec2012. Good physical condition, no rusting evident.

The burner tubes should be installed with the holes up or down?

No airflow restriction.