Raypak atmos intermittent ignition failure

[sromero100]

1 1/2 year old lightly used unit

When demand exists, spark occurs and does not light....ignition failure.

The next day it may work fine.

I replace the gas valve and unfortunately the problem still intermittently persists. I checked all the grounds and cleaned the connections. The control board looks like it works normally.

It seems like the problem may occur more when moist weather but could be my imagination.

Any hints or advice? I am leading towards either low grade fault in controller or some ground problem I have not figured out.

 

[1poolman1]

1 1/2 year old lightly used unit

When demand exists, spark occurs and does not light....ignition failure.

The next day it may work fine.

I replace the gas valve and unfortunately the problem still intermittently persists. I checked all the grounds and cleaned the connections. The control board looks like it works normally.

It seems like the problem may occur more when moist weather but could be my imagination.

Any hints or advice? I am leading towards either low grade fault in controller or some ground problem I have not figured out.

Ray Pak atmospheric heater? Are you sure it doesn't light the pilot, or just never recognizes it being lit? Best to use a small mirror to see or you have to lay on the ground to see the pilot. There is a green wire that attaches to the main valve, be sure it is not a little corroded. Pulling it off the valve and back on is usually enough. Sometimes an additional ground is needed from one of the screws that hold the burner tray in place to the cabinet. Just find another screw in the cabinet to attach the wire. Be sure there is no corrosion/rust at the screws that hold the try in place.
The flame sensor, the fork above the pilot flame, may need cleaning. Use a mild abrasive, not sandpaper. Means removing the burner tray. You may have done so to install a new valve.

 

[sromero100]

Thanks for taking the time to respond

Today I went out to check on your questions,,,,it is warmer and dryer......the unit fired right up. I could be way off base but the only hint I have is how wet, cool and humid...although inside the unit it is obviously dry. Hard to fix when not broken but frustrating when it won't turn on for a hot spa.

 

[ajw22]

You have corrosion on a ground or wire connection intermittently killing your flame sense circuit.

Dampness increases the resistance which kills the flame sense.

When it is dry the circuit is fine and things work.

 

[sromero100]

yes that makes sense

the odd thing is that there is no visible corrosion. I have also checked every connection and cleaned with electrical contact cleaner

 

[ajw22]

Corrosion is often not visible. Read about how sensitive the flame sense circuit is at Heater Flame Sensing - Further Reading

Thst is why poolman said above:

Sometimes an additional ground is needed from one of the screws that hold the burner tray in place to the cabinet. Just find another screw in the cabinet to attach the wire. Be sure there is no corrosion/rust at the screws that hold the try in place.

These types of intermittent problems can be very frustrating to find and fix.

 

[sromero100]

Yes I will add an additional ground and recheck connections again.....maybe add dielectric past

Thanks for the inputs

 

[sromero100]

so this morning west coast of florida had huge rain.....unit worked two days ago but now it will not light.

So will will check all connections but do you think I should add a new cabinet ground to the earth? Just not sure. So any advice is appreciated.

Steve

 

[ajw22]

So will will check all connections but do you think I should add a new cabinet ground to the earth? Just not sure. So any advice is appreciated.

Don't ground to the earth.

While it is called a "ground" the cabinet metal is used as the circuit path for the flame sensing. Instead run a wire from the burner tray that holds the flame sensor to a screw in the cabinet sheet metal.