New video Understanding Boiler Flame Signals

RayWohlfarth

In this weeks video, it discusses flame verification with a focus on flame rods. I talk about the causes of flame failures when using a flame rod. It also discusses why the industry switched from thermocouples to flame rods in the smaller boilers Hope you like it.

https://www.youtube.com/watch?v=t8x61mJBe60

EBEBRATT-Ed

Always had trouble with flame rods and consider them unreliable. I have cleaned hundreds of them, cleaned the ground path, the flame rod, ran separate ground wires everything. Sometimes they work and then they don't.

Some controls like the Siemens LFL do not have test jacks and you have to wire your meter in series with the FR. Riello gave up on the flame rods and went to ultraviolet.

That being said a Flame rod is the safest flame detector because it uses the flame for circuit conductivity that is if you can get them to work. Rooftop MU air units frequently came with FR detection and didn't work well. I converted many to UV

Flame rods are only for gas, not oil.

Ultraviolet can be used on oil and gas but works better on oil which has more UV light.

I always found flame rod signals weak and erratic

Infrared (otherwise known as lead sulphide) works on oil or gas.

I have always found that the MFG recommended flame signals are on the low end. What they tell you is the minimum reliable signal is usually lower than what you need for reliable operation.

The signal also needs to be relatively steady. A higher signal that is erratic is worse than a lower steady signal.

It is also better to use an analog meter for flame signals. You can see the meter needle move. Some digital meters can't move fast enough to catch the low and high meter readings

Peregrine

thanks you

RayWohlfarth

@EBEBRATT-Ed I agree I believe in a conspiracy theory that flame rods on rooftop units will always need cleaning on the coldest day of the year with the wind blowing

@Peregrine Youre welcome

Danny_Jr

Ray thanks for sharing. It is always good to review the fundamentals. I want to share a recent experience we had. We replaced a Weil-McClain LGB-6 steam boiler with like kind. The unit we replaces was only 20 years old and had been poorly piped. So my main focus was on cleaning up the near boiler piping to get dry steam. We ordered it with the CSD-1 package. Of course all the ignition controls are field wired on these larger boilers. When we fired it, it ignited fine. But while we where waiting to get the stone cold system up to pressure it locked out a few times. When I looked to see how my tech had wired it I noticed a control that was not on the old boiler we removed. It was CSD-1 Pulse relay. The micro amps would drop for just a fraction of a second and this relay would drop and we have to reset it. Well one of the things that I usually do it check the size of the gas pipe. This time I overlooked it. What we discovered is that the gas drop was 1-1/2" But they reduced it at the gas cock to 1". I was only about about 25+ equivalent feet with fittings. We replaced that 1" with 1-1/2" from the gas cock to control vestibule at which point the gas manifold was 1". That corrected the problem. Have not seen one of these pulse relays before and don't fully understand how they work. But it was very sensitive.

Thanks,

Dan Wood

Kalamazoo MI

EBEBRATT-Ed

Never heard of a pulse relay, sounds like a PITA

RayWohlfarth

@Danny_Jr Wow great catch I have never seen one of those either

@EBEBRATT-Ed I agree