Heater cycles & boom blows Door Off

[sjredeker]

Raypak Digital 406A several years old. Natural Gas. Starts, heats then in about 10 minutes loud boom (explosion) and access cover is blown off, repeats explosion every 5-10 minutes. Turned off power at house main electrical panel. Replaced control board, did not fix problem. Removed disassembled & inspected burner, no dirt, cobwebs, minimal corrosion. Removed igniter & inspected, some corrosion. HELP! Thanks....

 

[ajw22]

Welcome to TFP.

Post pictures of your heater.

Pentair does not have a Digital 406A model. Raypak has a 406A model.

We need to know what unit we are discussing.

 

[sjredeker]

Welcome to TFP.

Post pictures of your heater.

Pentair does not have a Digital 406A model. Raypak has a 406A model.

We need to know what unit we are discussing.

Oops. Raypak.

Welcome to TFP.

Post pictures of your heater.

Pentair does not have a Digital 406A model. Raypak has a 406A model.

We need to know what unit we are discussing.

Oops. Raypak. Also inspected top vent area, all clean & not obstructed.

 

[JamesW]

several years old.

Date of installation?

 

[JamesW]

Looks like September 2005, which makes it about 19 years old.

Raypak Serial Numbers.​

Before 1995, it was month (first 2 digits) and then year (digits 3 and 4).

Beginning in 1995, they changed to year and month. The first 2 are the year and the next 2 are the month.

Serial number 1604304448 was made in April 2016.

RayPak Heaters - Further Reading

www.troublefreepool.com

 

[JamesW]

Check the heat exchanger for sooting.

 

[ajw22]

Clean the burner orifices. Read RayPak Heaters - Further Reading

 

[ajw22]

Have you bypassed any of the safety sensors?

 

[JamesW]

Service Menu and Fault History.​

To access the Service Menu and fault history, press the MODE and UP buttons simultaneously for 3 to 5 seconds. The heater will continue to operate normally while in the Service Menu. The first screen displayed is the Flame Strength indicator, which indicates the pilot flame current using a bar graph and numerical display. A signal of less than 4 indicates a weak flame signal and may require service. Refer to Section 5 Troubleshooting for possible causes and corrections.[19]

Press the DOWN button. The Supply Voltage screen indicates the voltage supplied to the control board. Normal readings range from 24 to 29 volts.

Press the DOWN button. The Run Time indicates the total hours of operation for the pool heater, as measured by the amount of time that the main gas valve has been powered. The Cycle count indicates the number of on/off cycles of the heater, as measured by the number of times the pilot valve has been powered.

Press the DOWN button. The Fault History can display up to ten faults in memory. The order of the faults begins with “Fault Last,” which is the most recent fault, and proceeds through ten most recent messages in chronological order. The second line of the display shows the fault message. If there are no faults in the history buffer, the second line reads “All Faults Clear.”

 

[JamesW]

P-R406A-EN-C

https://www.poolsinc.com/pdf/raypak/raypak-digital-heater-product-manual.pdf

https://s3.amazonaws.com/AWSProd/sites/raypakcom/documents/241236.pdf

https://s3.amazonaws.com/AWSProd/sites/raypakcom/documents/6500.00.pdf

Digital Gas Heater

Digital – Raypak

Raypak Pool & Spa, Residential and Commercial Hydronic Products -

www.raypak.com

 

[JamesW]

Heat Exchanger Assembly, 010046F

 

[sjredeker]

As noted in original posting, everything, burner etc) has been inspected...found clean, no blockages, no sooting, nothing out of the ordinary.....Clean the burner orifices.l; nothing bypassed. replaced circuit board....still explodes. do not want to run to look at readout...explodes. Steve Read RayPak Heaters - Further Reading

 

[JamesW]

Check the Fault History.

Check the gas pressure.

Can you show a picture of the heat exchanger?

 

[1poolman1]

Pentair Digital 406A several years old. Natural Gas. Starts, heats then in about 10 minutes loud boom (explosion) and access cover is blown off, repeats explosion every 5-10 minutes. Turned off power at house main electrical panel. Replaced control board, did not fix problem. Removed disassembled & inspected burner, no dirt, cobwebs, minimal corrosion. Removed igniter & inspected, some corrosion. HELP! Thanks....

Your burner orifices, especially the ones on the right side of the cabinet, are likely clogged with spider nests. You will have to remove the tray again and maybe even remove each orifice (7/16" wrench) to clear them. Use a copper wire 14g, to clear the orifice, not steel, as that can damage the opening. If you have a very small brush or pipe cleaner, that will work as well.
Firing the heater for 5 minutes at least once a month helps keep spiders away, weekly is better.

 

[sjredeker]

Check the heat exchanger for sooting.

Clean.

 

[sjredeker]

Your burner orifices, especially the ones on the right side of the cabinet, are likely clogged with spider nests. You will have to remove the tray again and maybe even remove each orifice (7/16" wrench) to clear them. Use a copper wire 14g, to clear the orifice, not steel, as that can damage the opening. If you have a very small brush or pipe cleaner, that will work as well.
Firing the heater for 5 minutes at least once a month helps keep spiders away, weekly is better.

Inspected. no evidence of spider webs. Would they be INSIDE the orifice, inside the 3/4 inch gas pipe? Also cleaned all with copper wire but not tested yet.

 

[sjredeker]

Check the Fault History.

Check the gas pressure.

Can you show a picture of the heat exchanger?

How to check fault history? Heater is currently disassembled: burner tray, gas valve etc removed. Hx has minor corrosion but is not obstructed. will need to disassemble top again to get picture.

 

[sjredeker]

How to check fault history? Heater is currently disassembled: burner tray, gas valve etc removed. Hx has minor corrosion but is not obstructed. will need to disassemble top again to get picture.

 

[JamesW]

010410F

Can you show the burner tray?

Seems like you are getting an accumulation of unburned gas that is suddenly igniting.

Maybe obstructed burner tubes.

Can you show pictures of the burner tray and the heat exchanger?

An Atmospheric Model does not have a blower and it relies on the natural draft created by hot air rising.

There are probably blockages in the burner tubes and the heat exchanger.

There might be a variable gas pressure causing surges.

Maybe a bad gas valve or maybe a bad gas pressure regulator.

Is the gas supply low pressure (7") or high pressure(2 psi)?

 

[JamesW]

Service Menu and Fault History.​

To access the Service Menu and fault history, press the MODE and UP buttons simultaneously for 3 to 5 seconds. The heater will continue to operate normally while in the Service Menu. The first screen displayed is the Flame Strength indicator, which indicates the pilot flame current using a bar graph and numerical display. A signal of less than 4 indicates a weak flame signal and may require service. Refer to Section 5 Troubleshooting for possible causes and corrections.[19]

Press the DOWN button. The Supply Voltage screen indicates the voltage supplied to the control board. Normal readings range from 24 to 29 volts.

Press the DOWN button. The Run Time indicates the total hours of operation for the pool heater, as measured by the amount of time that the main gas valve has been powered. The Cycle count indicates the number of on/off cycles of the heater, as measured by the number of times the pilot valve has been powered.

Press the DOWN button. The Fault History can display up to ten faults in memory. The order of the faults begins with “Fault Last,” which is the most recent fault, and proceeds through ten most recent messages in chronological order. The second line of the display shows the fault message. If there are no faults in the history buffer, the second line reads “All Faults Clear.”

How to check fault history?

https://www.poolsinc.com/pdf/raypak/raypak-digital-heater-product-manual.pdf