Is that with gain control on the amp set at max?

No, I don't have it set up now so I can't do anything. maybe tomorrow I'll have more info but it has to be able to detect the flame when the burner is low, so I don't see why it wouldn't also detect the flame from the lighter to start the burner.

 

OK. It's important to know exactly how much voltage is available when the burner is at min and max.

 

I think all that maters is if the solenoid opens with a min. flame.

 

Agree but need to know what that voltage is and if it's stable.
When you get some more info will be better able to decide what will work best

 

Agree but need to know what that voltage is and if it's stable.
When you get some more info will be better able to decide what will work best

So the most I can get from a stable flame is still less than 1 volt

 

How much less?

 

How about using a light sensor to detect the flame?

 

How about using a light sensor to detect the flame?

NO!!!

Using a mosfet transistor it will be the output voltage that matters, not the current. There needs to be enough voltage to provide full saturation for the 220 MA current.

Do you know how I could test this and find which terminals would connect to the flame sensor? 520814 Ignition Control Circuit Board Igniter Module Replacement Parts Kit Fit For Suburban RV Water Heater & Furnace, For SW4D, SW6D, SW10D, SW12D, SW16D RV Water Heaters, Replace 520820 520871 If I could figure out which wires connect to the flame sensor I may be able to use this.

 

NO!!!

Could explain why?
Can't open that link.

 

not all flames emit visible light which (methanol...). also using light means sensitivity to false triggers from ambient so flame may not be present even though signal would suggest that it is. since the main goal of flame detectors is to cut off fuel supply when there is no flame, such false readings could lead to a very dangerous situation (explosion).

 

Because of the safety function, I suggest using an off the shelf burner controller such as (12V RV) Fenwal

Safety standards require a flame sense (circuit) to constantly do a self-check. So the excitation voltage will be briefly turned off with an expectation of seeing no flame detected, then the excitation is turned back on, all within a second or two. To see if anything is "stuck".
If you get it wrong, a false positive and leave the gas solenoid on in a flame-out situation, there is an explosion hazard.
I have seen this happen with garbage design flame sense circuits.

 

Haven't received an answered to my question back in post #46. There's still a possible relay solution even with a low voltage out from the amp.

I'm not clear about where the voltage is being picked off.

Ionic flame sensing, it does not generate a known voltage. It's thermionic emission same as a vacuum tube diode, so a uA current flows in one direction in the presence of high voltage.
Some burner flame-sense circuits use 24VAC, most are using HV 90VAC excitation though to get up to 10uA.

A no-no is using a CMOS gate and say 10MEG pullup resistor, because flame rod (porcelain) contamination (carbon, soot, combustion moisture, condensation) acts as a leakage current or pulldown. This is not a flame lol.
Safety standards specify flame-sense circuits "must rely on the rectification property of the flame".
So tossing a wet noodle on the flame rod must not be seen as flame present, a false positive. Again a bad untested uncertified design, this causes explosions.

If you are "snooping" on the flame rod voltage, with say a high impedance op-amp circuit, many igniters use the same flame-rod for spark so the op-amp needs protection. As well, the MCU self-check will intermittently turn off AC excitation to the flame rod for the self-test. So the signal is not constant.

Depending on the combustion safety standard, size of burner - you must shut off the gas solenoid with X seconds of a flame out being detected.

 

So the most I can get from a stable flame is still less than 1 volt

Still waiting for an answer to post #46.
There's still a possible relay solution even with a low voltage out from the amp.

 

I'm not clear about where the voltage is being picked off.

I mistakenly quoted your post.
The question was suppose to be directed to the TS.

 

I thought I could use something like this if I could figure out how to connect it because I only need the solenoid controlled by the flame sensor. I won't have an igniter or anything else just the solenoid switch. I've been looking but can't find any data for it. There are other RV furnace boards that may work if there's a way to bypass the other switches.
https://www.ebay.com/itm/2354720034...q9jVcKFSBCVpjqZL49RSW/fIWpY=|tkp:BFBM9MT76qtl


Fit For Suburban SW 520814 Water Heater Ignition Control Board Module Board

 

I'm not clear about where the voltage is being picked off.

Ionic flame sensing, it does not generate a known voltage. It's thermionic emission same as a vacuum tube diode, so a uA current flows in one direction in the presence of high voltage.
Some burner flame-sense circuits use 24VAC, most are using HV 90VAC excitation though to get up to 10uA.

A no-no is using a CMOS gate and say 10MEG pullup resistor, because flame rod (porcelain) contamination (carbon, soot, combustion moisture, condensation) acts as a leakage current or pulldown. This is not a flame lol.
Safety standards specify flame-sense circuits "must rely on the rectification property of the flame".
So tossing a wet noodle on the flame rod must not be seen as flame present, a false positive. Again a bad untested uncertified design, this causes explosions.

If you are "snooping" on the flame rod voltage, with say a high impedance op-amp circuit, many igniters use the same flame-rod for spark so the op-amp needs protection. As well, the MCU self-check will intermittently turn off AC excitation to the flame rod for the self-test. So the signal is not constant.

Depending on the combustion safety standard, size of burner - you must shut off the gas solenoid with X seconds of a flame out being detected.

Thank you, very good advice! I won't try anything silly. I'm just trying to make the gas shut off if the flame goes out.

 

Nice, but still waiting an answered to my question in post#46 please.

 

Nice, but still waiting an answered to my question in post#46 please.

The question is answered in #52, prairiemystic is correct. I want to use an off the shelf module, but they all have igniters, I'm lighting this manually. I only need the flame detector to shut off the power to the solenoid if the flame goes out, but it must work the same way as all the gas furnaces, a light sensor will not work.

 

The answer is not in post #52.
I want to know what the actual measurement was in volts in post#45
Another option is to use two of those amps
( or other ones available ) in a series arrangement to boost the voltage further to the level required.

 

Also need to confirm if the flame sensor is connected correctly to the amp and adjusted properly.
There is a good chance that a single amp module can work.