Blodgett Convection Oven

[Joseph12345]

Model DFG 100/200 w/cook 115v

Looked at one today, customer said it dosent heat up. Took it apart, when I cut it to cook and set the temp up the pilot lights immediatly and the sparker just dosent stop sparking at all. The pilot just stays lit, no main gas and sparker just keeps going. I'm picking up a proof of flame rod in the morning to put in. Any suggestions as why my opinion on what's wrong is incorrect?

[RussS]

I can't count how many times I cleaned a spark rod and it started working.

I've replaced some too, but you need to find out which part isn't working. Age counts here.

I just replaced a 16 yr old Trane ignition module, it looked good, but didn't turn on the gas valve.
Also the inducer motor was running at about 80% normal speed, it got replaced too.

This could be the ignition module, the pilot sensor, the wire off the sensor, the pilot drill size clogged, or piping not delivering. I've walked into service calls where the owner was "working on it" right before hand, forgot to tighten a couple terminals...

Make sure the wiring is in the right locations / terminals. Tighten them ALL.
Get the wiring diagram. I can't tell ya how many times a manufacturers wiring diagram saved my butt! lol

or see if the manufacturer has a conversion to a glow bar module. an upgrade?

[ECtofix]

Model DFG 100/200 w/cook 115v
I'm picking up a proof of flame rod in the morning to put in. Any suggestions as why my opinion on what's wrong is incorrect?

RussS is correct on your needing to ensure all else is in good order. Especially the integrity of ALL flame sensing circuit connections - from module to flame sensor electode...AND all ground connections in between.

You ARE correct on it likely being the flame sensor. That's a common issue on Blodgett ovens.

You said you have a pilot flame with continuous sparking, but no main burner. In such a situation, I usually elliminate wiring/connection issues or a weak flame by doing a visual inspection. If good, I'll remove the burner assembly to access and scuff the flame sensor rod to shiny metal with some sandpaper. After reassembly, usually the oven will prove flame and operate properly. If NOT, THEN suspect the module as the culprit.

If cleaning that flame sensor seems to get it working, then DO plan to replace it anyway. That flame sensor electrode has degraded from a process called "silicone migration", so a mere cleaning would be a short-lived repair. Cleaning it WILL get them through until you return with the new part.



Blodgett won't have a conversion kit to a "glow rod", commonly referred to as a Hot Surface Ignitor (HSI). Blodgett has made the same basic oven design for years and is one of the most dependable on the market, so doubtful they would change now. Beside, Southbend (another oven maker) DOES use the HSI ignition and those have their own set of problems. HSIs are fragile and may give out on the next aggressive "slam" of the oven door.There's no intermediate fix to get them through either - so they're down until you return with the part.

[Joseph12345]

Thanks for the great technical responses. I've done those suggestions before such as cleaning a thermocouple/pile and it working until the new one is replaced. But it way to many cases, sadely if you DO make it work until you get the part, the customer automatically assumes its working and dosent want you to return to fix.

[RussS]

That's okay, no one is born with marketing skills.

You really need some marketing advice.

Get them to sign your service agreement with the price of the repair, and take the broken part with you.

If it's a critical need service call, go get the part, and charge them for that.

Marketing and sales are different than heating and cooling.

Sign up online for some free marketing skills classes, and learn how to satisfy the customer's needs.

You'll make much more money, and your customers will be way happier right away.

Russ

Thanks for the great technical responses. I've done those suggestions before such as cleaning a thermocouple/pile and it working until the new one is replaced. But it way to many cases, sadely if you DO make it work until you get the part, the customer automatically assumes its working and dosent want you to return to fix.

[CFESAmasterEGSR]

Some things to keep in mind for better results when dealing with flame rectification systems.

Firstly, this in conjunction with spark ignition is probably the most reliable type of flame management. Though I prefer separate spark and sense wires/rods, I think this oven uses two if I remember right.

Second, a flame rectification "flame sensing" system is an electrical circuit. There is a current flow through the flame. Power travels from something to something else. Just cleaning the flame sensor is only one part of that circuit. I think on this blodgett, the other half of the circuit is the pilot hood/deflector as "ground". If BOTH parts of any flame rectification system aren't cleaned, your wasting everyone's time.

Third, when cleaning these parts, you don't want to scratch the heck out of the metal surface with sand paper or emery cloth, you want to polish the surface and hopefully leave smooth metal surface similar to a new one. Carry or grab in the kitchen a scotch brite pad, you know the green ones. Or if in a pinch, steel wool. Any manufacturer that knows their stuff will tell you "yes green scratch pad" and "NO sand paper".

Also, I never saw you mention any micro-amp readings. Did I miss that? Any, any, any time you think or even know you have a flame sensing issue, first step should be a micro amp reading. Then you KNOW which part of the system to go at, your not guessing. Check which style module your dealing with, learn the common or lookup the micro amps required to satisfy the specific control you have.

Know what your doing, don't guess. That will lead you to knowing what's wrong instead of guessing.

Oh, and "sell them a service agreement"?? Is this a tech blog or sales blog? I'm sorry but that is a salesman's response. Do the repair right. Learn it right. Be honest with the customers. That will lead you to efficient repairs of their stuff. Word gets around that "this guy actually know what he's doing!" And remember, managers float around in Foodservice. Be the bigger man and fix it right and be able to explain why, and you'll have more work than you'll know what to do with.

Sorry, not meaning to be rude, I just hate seeing possibly good techs fall down the trap of "you need this part".

Good luck -OP

[RussS]

Some things to keep in mind

Know what your doing, don't guess. That will lead you to knowing what's wrong instead of guessing.

Oh, and "sell them a service agreement"?? Is this a tech blog or sales blog? I'm sorry but that is a salesman's response. Do the repair right. Learn it right. Be honest with the customers.

Sorry, not meaning to be rude, I just hate seeing possibly good techs fall down the trap of "you need this part".

Good luck -OP

Good day,

First of all, that's not what I said, and that's not the context of my statement.

There's not a thing wrong with someone working with people, taking money from them, oh wait, that's selling.

I've been a tech in our industry for 38 years, and I also satisfy my customer's need for a transaction that gives them what they want. No matter what that is.

Yep, I sell. And for that, I make pretty good money.

Back in the day, the butt crack showing service guy with a ripped up rock tee shirt and blue jeans could get away with laughing at the customer.

But not any longer. We use marketing and sales to generate income and maintain continuity in business.

There's lots of reasons for technicians to sell, but we won't go into stuff like baby food, gasoline and insurance money for their boats.

Just the fact that customers are not loyal anymore, and they can thumb the yellow pages for the next graduate, is enough for me to want to keep my customers so satisfied that they tell other techs they might want to put in an application at my company.

If you don't sell, don't use marketing and strategize your company to the top, you can just fill out an application and we'll get back to you.

Have a swell day,

Russ
Technician / Owner

[ECtofix]

Any, any, anytime you think or even know you have a flame sensing issue, first step should be a micro amp reading.

No doubt that the microamp feature on DMMs is capable to do so on MOST flame circuits used in cooking equipment. However, Blodgett uses a Johnson Controls ignition module that has a flame current well below a DMM’s range. To read its flame current, you will need a signal transducer (Blodgett P/N 22310) to use in conjunction with your DMM. Parts Town lists it at around $200.

When cleaning these parts, you don't want to scratch the heck out of the metal surface with sand paper or emery cloth, you want to polish the surface and hopefully leave smooth metal surface similar to a new one. Carry or grab in the kitchen a scotchbrite pad, you know the green ones. Or if in a pinch, steel wool. Any manufacturer that knows their stuff will tell you "yes green scratchpad" and "NO sand paper".

Absolutely should be standard knowledge and practice. So yes...ALWAYS take the time to properly polish the flame sensor electrode using materials mentioned...IF the cleaning IS the conclusion of your repair.
However, per a Blodgett Field Rep in one day seminar I attended a dozen years ago, “silicone migration” has likely degraded the existing flame sensor rod, so merely cleaning/polishing it would be a short-lived repair and should ALWAYS be replaced. It's only a $12 part, so I always kept a few in my truck inventory (P/N 18256).

[CFESAmasterEGSR]

RussS-

I think we are straying away from the OP's technical question. Yes, image and attitude is a lot in today's market. And yes, I know a lot about "sales" I guess, I "sold" around $250k of my labor to my very happy customers last year. Maybe were not on the same page here, what exactly do you mean by "get them to sign your service agreement"? I took that to mean you pay me $xxx per year and we take care of all issues with your equipment. If that's not what you meant then we got off on the wrong foot here, and I apologize. It's possible I misread your post. Quality workmanship and honesty with your customers builds customer loyalty. It does still exist, it just has to be developed.

[Joseph12345]

At least the oven is working now...

[Randallsintegrity]

RussS-

I think we are straying away from the OP's technical question. Yes, image and attitude is a lot in today's market. And yes, I know a lot about "sales" I guess, I "sold" around $250k of my labor to my very happy customers last year. Maybe were not on the same page here, what exactly do you mean by "get them to sign your service agreement"? I took that to mean you pay me $xxx per year and we take care of all issues with your equipment. If that's not what you meant then we got off on the wrong foot here, and I apologize. It's possible I misread your post. Quality workmanship and honesty with your customers builds customer loyalty. It does still exist, it just has to be developed.

I don't think you should have apologized. It's pretty clear that guy is an owner who is too far from the reality of things. In other words he hasn't held a wrench in a few years. Good reply to the OP, give him guidance to fix his issue not some lame sales pitch. I hope Russ is no longer in business, we don't really need those guys, they can go work for a manufacturer. Any contractor who is bothered with sales doesn't know what they are doing. You don't need people skills other than "how's it going", you just say here is your invoice, it's fixed, the customer doesn't care what was wrong, they don't even care what it cost most times, they just don't want to call you back for the same issue. Be that third party commercial, residential, mom & pop, etc. They don't care what you have to say as long as you say that you won't see them again for awhile. The sales in this occupation is to say less and do more. No manager knows what a module is, what it does, how it works, they don't care. They care if their oven is 350 degrees when they flip the switch to cook...period. They are worried about selling 50k worth of food that month and who didn't show up for work. That's 12 years into HVACR and kitchen equipment, I worked for everybody, then started my own business. Business is good and I haven't knocked on a door in 4 years. They come to me, and I tell them happy to get your business or not accepting new customers, depends on who they are. That is an owner that still picks up a wrench......volt meter, gauges, recovery machine, vacuum pump, pulls filter up by a rope, sweats on roofs, and still has time to manage quickbooks. There are people who do it for the money and people who do it because it seems nobody else can do it right. Every full-time tech bills 250k a year. What was the profit and what was the customer satisfaction?