Boiler Will Not Fire

Richard Edington

I am having a heck of a problem with a boiler that I am unfamiliar with and am hoping that someone has seen and repaired this problem.
The boiler is a Raypak H4-0090B cooper fin boiler built in 1993. It will not fire after it drops down to 150 degrees. You can interrupt the power and it will re-fire and run great up to its set temperature of 180 degrees, but then shuts down after reaching 180 and cools down to 150 degrees. As the boiler reaches 150 degrees the sensor will send a signal for more heat, will send a signal to the hot surface igniter, and will glow red-hot for approximately 28-29 seconds, the gas valve is powered and opens for approximately 3 seconds but IT WILL NOT LIGHT.
The Honeywell S8910U1000 will give an error code of ignition failure and not try to relight again if. If, however, you let the boiler set for a few minutes and turn the power to it off and then on again, it will fire up like it is supposed to and run up to 180 degrees again, then shut down and start the process over again. There is gas flowing thru the gas valve as I could light it manually with my torch. The Allen head on the outlet side of the meter was stripped so I could not test it with my manometer).
Things that were done or checked per the service tech at Raypak:
1. Check resistance to the HSI. It was ok registering approx. .75.
2. Checked the position of the HSI. It was ok.
3. Install a new S8910U1000 universal hot surface ignition module to replace the S89C.
4. Run a new ground wire to the burner plate from the HIS module.
5. Check for 24 volts running to the ignition module while it was trying to light. The volts checked out ok.
6. Checked the inlet gas pressure, it is an 8" water column static pressure and drops to approx. 6-inch water column when it tries to fire. The tech said that it should fire at 4" of water column.
After going through all of the potential problems the tech at Raypak suggesting changing over to a standing pilot light.
Please help if you can.
Thank you!

Al Corelli_2

Check..

Recheck the ground connections, from burner plate to controls to REAL ground.

Check to make SURE the hot and neutral are not swapped.

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Richard Edington

Raypak H4-0090B Boiler Still Will NOt Fire

Continued from my message yesterday. I ran a new ground wire from the S8910U1000 hot surface ignitor to the burner tray. The polarity is correct on L1 and L2, but it still will not light. I would appreciate any other suggestions.
Please see my message posted yesterday for the complete history.
Thank you for any help given.

Ed_26

raypak

Did yu check for voltage @ gas valve? You could have a poor/intermittant voltage, or an intermittant gas valve operator. (replace gas valve)

Dan_38

ignition problem

try adjusting manifold gas pressure. also may have something to do with high draft when boiler is hot.

Richard Edington

Boiler Still Will Not Fire

I checked the voltage at the gas valve. It was okay and read 24 volts when it is trying to fire. I ran new connections from the HSI module to the burner tray with no improvement. I also checked to be sure the hot and neutral were not swapped and they checked out okay. I will recheck the manifold pressure today and if it is still not working, I am planning to change to a standing pilot in hopes that will fix it. I am still looking for more suggestions and appreciate all the help so far. Thanks!

Ed_26

raypak

> I checked the voltage at the gas valve. It

> was okay and read 24 volts when it is trying to

> fire. I ran new connections from the HSI module

> to the burner tray with no improvement. I also

> checked to be sure the hot and neutral were not

> swapped and they checked out okay. I will

> recheck the manifold pressure today and if it is

> still not working, I am planning to change to a

> standing pilot in hopes that will fix it. I am

> still looking for more suggestions and appreciate

> all the help so far. Thanks!



Remove one burner (away from ignitor) & put manometer tube on the orifice. test fire the thing to see if your man. press. is to spec. You may need to cycle it a few times to get an idea of what's happening. (gas valve issue)

Ed_26

raypak

Remove one burner (away from ignitor) & put manometer tube on the orifice. test fire the thing to see if your man. press. is to spec. You may need to cycle it a few times to get an idea of what's happening. (gas valve issue)