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-   -   Possible direct spark ignitor alternative. Robertshaw 785-001 (http://www.homebrewtalk.com/f51/possible-direct-spark-ignitor-alternative-robertshaw-785-001-a-381828/)

rickyspeak 01-16-2013 12:36 AM

Possible direct spark ignitor alternative. Robertshaw 785-001
 
I stumbled across this the other day and I was wondering what the various experts out there had to say about the Robertshaw 785-001 as an alternative direct spark ignitor. Obviously it is less safe than a Honeywell ignition control module, but it seems like a good alternative for those who are willing to be less safe.

The big issue is that I can't find any specific information on what it does. IE does it just continuously spark or does it flame sense. Does anybody out there have specific personal knowledge on what this does and how it works?

Crimsonwine 01-23-2013 02:47 AM

Quote:

Originally Posted by rickyspeak (Post 4789612)
I stumbled across this the other day and I was wondering what the various experts out there had to say about the Robertshaw 785-001 as an alternative direct spark ignitor. Obviously it is less safe than a Honeywell ignition control module, but it seems like a good alternative for those who are willing to be less safe.

The big issue is that I can't find any specific information on what it does. IE does it just continuously spark or does it flame sense. Does anybody out there have specific personal knowledge on what this does and how it works?

I am totally looking into the same thing as you and I have the same question...what I can find does lend itself to being flame sensitive..but doesn't directly say so....

I think it would be safe if it is wired inline with the gas valve...

I can't see dropping over $200 for a Honeywell system per burner...

I use a standing pilot now and have never had a problem...but then again I do watch it like a hawk....

Hopefully someone with experience can chime in...

reynolds5520 01-23-2013 03:12 PM

It took some searching but I found the installation manual.

Basically, you apply power and turn on the gas to the pilot, the module then sparks until it senses the pilot flame. If the pilot goes out, it sparks again.

The downside is that there is no control of the gas flow in this. It is designed to be used with a gas valve that has its own sensors to shut off the gas.

This isn't what I would use to automate a gas burner.

Crimsonwine 01-23-2013 03:45 PM

Quote:

Originally Posted by reynolds5520 (Post 4816643)
It took some searching but I found the installation manual.

Basically, you apply power and turn on the gas to the pilot, the module then sparks until it senses the pilot flame. If the pilot goes out, it sparks again.

The downside is that there is no control of the gas flow in this. It is designed to be used with a gas valve that has its own sensors to shut off the gas.

This isn't what I would use to automate a gas burner.

Thanks for the effort!

I am thinking this should be wired in series (or parallel) with the gas valve. I have a PID that energizes my gas valve open....

When the PID calls for gas, it will also energize the spark module at the same time causing the BG-14 burner to ignite...

When the PID senses temp is met it shuts off the gas valve and power to the spark control so it does not keep sparking...

My MLT and HLT are preset so the flame is always the same....

rickyspeak 01-24-2013 05:15 AM

Great find reynolds5520. I couldn't find a manual anywhere. That answers all my questions. Basically this item has the same ignition functionality that the Blichmann Tower of Power provides (plus a solenoid valve of course). I'd say it's a little less safe than a standing/intermittent pilot light. All together it would be cheaper though. Which is good.

FYI Crimsonwine. You'd want to wire them in parallel. The voltage drop that putting it in series would cause might make it no longer work. Especially with a AC to high voltage DC converter that would be needed for the spark.

whatdyisit 01-24-2013 06:32 AM

These units are traditionally installed in furnaces with pilots that have bi-metal switches in them, sometimes referred to as "3-wire pilots". Once these units light the pilot, the heat closes the bi-metal switch and sends power to the main valve terminal on the valve. Outdated technology and can get pretty pricey. You would not want to direct fire the burner with these. A light breeze could blow the gas mix off the spark and you could end up with a big flash and no eyebrows.

reynolds5520 01-24-2013 02:02 PM

Quote:

Originally Posted by whatdyisit (Post 4819974)
You would not want to direct fire the burner with these.

Agreed, in fact, it didn't even occur to me that anyone would be thinking to directly ignite a burner with these.

The only way I would use it, is to ignite a standing pilot. Just as a way to avoid having to reach in with a manual lighter at the start of the brew session. There are cheaper alternatives for that simple use, like the barbeque click button ignitors. The only advantage to this unit is that it relights the pilot automatically and that isn't enough to make for a safe unattended burner.

rickyspeak 01-25-2013 03:40 PM

I wasn't trying to imply that it was entirely safe. Even manual ignition isn't safe. I know I've had more than one time where I was fumbling with a blown out lighter and gotten a small boom. It definitely would be a nice added feature to a standing pilot setup to protect from blowouts.

More I was looking for a DIY alternative to the tower of power ignition system for my own curiosity sake. There clearly is a commercial example of this sort of design.
The guy clearly explains that if you don't get ignition it just continues to beep at you resulting in and the same "explosive" potential.

If my interpretation is wrong about what the blichmann product is doing, I'd love someone to open the guts and show us all what it's actually using for DIY cloning fun.

Quote:

Originally Posted by reynolds5520 (Post 4820680)
Agreed, in fact, it didn't even occur to me that anyone would be thinking to directly ignite a burner with these.

The only way I would use it, is to ignite a standing pilot. Just as a way to avoid having to reach in with a manual lighter at the start of the brew session. There are cheaper alternatives for that simple use, like the barbeque click button ignitors. The only advantage to this unit is that it relights the pilot automatically and that isn't enough to make for a safe unattended burner.


whatdyisit 01-25-2013 10:54 PM

Yeah the Blichmann is doing exactly what you are talking about, sounds like a different ignition module though. I had a 785-00A in the back of the shop and so I wired it up and shot a video real quick so you can see how it operates.


Kyled93 02-25-2013 02:35 AM

1 Attachment(s)
Quote:

Originally Posted by whatdyisit
These units are traditionally installed in furnaces with pilots that have bi-metal switches in them, sometimes referred to as "3-wire pilots". Once these units light the pilot, the heat closes the bi-metal switch and sends power to the main valve terminal on the valve. Outdated technology and can get pretty pricey. You would not want to direct fire the burner with these. A light breeze could blow the gas mix off the spark and you could end up with a big flash and no eyebrows.

Ok, just stumbled across this thread as I currently use hot surface ignitors but want to switch to spark. This is primarily due to wanting to use true PID control not just on/ off temp control.

I am a bit confused at why you would not want to use this for the direct fire ignition? If I understand the above posts, this ignition system sparks until flame closes the bimetallic strip correct? My current setup is a bg 14 with timed relays and a hot surface ignitors. (see photo).


Attachment 103679



The other thought is this could potentially be a bit safer based on the automatically respark if the burner were to be blown out.


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