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#215033 - 02/23/15 08:59 PM Have you ever had one of those jobs.....
Potseal Offline
Member

Registered: 02/23/13
Posts: 187
Loc: Saskatchewan
Where you're trying to troubleshoot a problem and every time you think you have it solved it isn't? And to make matters worse it just goes on and on and eventually you start dreaming up wild theories because you've exasperated all other rational thinking?

I mentioned in another topic about the steam appliance that a plumber and I were working on and how we worked together to troubleshoot why it was shutting down. After several attempts and returning numerous times to stare at this miserable piece of equipment we are back at square one. I've exhausted the electrical end and he's gone through the plumbing numerous times. Together with advice from people who understand boilers we've tried to figure if there's a problem involving that piece of the puzzle and it still has us beat. I hate giving up but I'm almost there.

Now, if someone can direct me to a boiler guru.....
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A malfunction at the junction

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#215034 - 02/23/15 09:53 PM Re: Have you ever had one of those jobs..... [Re: Potseal]
twh Offline
Member

Registered: 03/11/04
Posts: 892
Loc: Regina, Sask.
I'm not a guru but I understand that it's nice to have a little moral support.

Is it domestic water, space heating, or both?

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#215035 - 02/24/15 12:58 AM Re: Have you ever had one of those jobs..... [Re: Potseal]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
Gas?
Did you throw a thermocouple at it yet? If it doesn't see heat pretty soon after the gas comes on it shuts down.
(my trick for today)
The first thing you have to do on a problem like this is figure out what CAN shut it down, then start eliminating those things.
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#215039 - 02/24/15 02:21 AM Re: Have you ever had one of those jobs..... [Re: Potseal]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
The last time something that zany happened, the plumber had thrown his shut-off valve - CLOSED - even as the GC thought that it was left open -- since the plumber had promised the GC that he would do so.

Poof, the gen-set started up.

It's often the case that a trooper forgets a commitment -- or gets a phone call from his office instructing him on 'house' policy: his own boss insists that the gas cock be turned off. Rather than explain this policy to the GC, the dude just split.

(This particular GC superintendent was a screamer... and in w-a-a-a-a-y over his head.)

It's only funny years later -- to those who didn't have to endure him.

&&&&&

With modern digital controls, you may have to jumper past such logic to establish that the 'dumb' aspect of the device/ machine actually fires up.

And as Greg has pointed out, always be suspicious of safety over-rides. These are now standard fare for all ignition schemes for fixed equipment -- especially in confined spaces.

You might find that the logic is set up with even remote air quality sensors to prevent detonations.

ANYTHING burning LP is ESPECIALLY touchy about gas build up.

These air quality monitors are touchy enough to even trip out over sewer gases -- or if they are still wrapped in anti-dust barriers. (In the manner of smoke alarm heads.)

And, ...

Why rack your brains when the production factory has FREE TECH ADVICE direct to your location -- by cell phone. With modern smart phones, you can even video the gear and the tech can see what you're seeing.

The way you're acting the factory tech is as busy as a Maytag repairman. These fellows are DYING to hear from you. If you never do, they're sure to lose their jobs.

So think about that.
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#215041 - 02/24/15 06:38 AM Re: Have you ever had one of those jobs..... [Re: Potseal]
Potseal Offline
Member

Registered: 02/23/13
Posts: 187
Loc: Saskatchewan
The plumber and I have both talked to tech support and they have the same answer - replace part A, B, and C. Those parts have already been replaced and I doubted the originals were faulty to begin with but when you start running out of ideas...

But to let you know specifically what we're dealing it's a Cleveland CSM24 Steam Coil Convection Oven. It uses building steam that runs through a coil in a boiler beneath the two heating compartments to heat the food grade water in the tank into steam. The building steam itself is not food safe which is why this system is used.

The basic problem is that the appliance operates for 3-4 hours and then shuts down. During the period of time when it fails we see the water in the sight glass go down but it doesn't appear that the probe in the tank that maintains the water level is signalling the circuit board to open the water fill valve. It takes approximately 20 minutes for the water to almost disappear from the sight glass and then the steam shuts off and it goes into a MANUAL reset mode. After it does it the first time it tends to happen every hour thereafter.

I placed 3 DMM's on the high probe, low probe, and water fill valve to see what was happening as far as if the signals were being sent. Every time we watched it shutdown we observed no change in voltage which despite the water level in the sight glass the water in the tank appeared to be covering the 2 probes and the water fill valve remained closed. We kept working on it from the point of that probes or circuit board were faulty but only during this time for reasons we could not explain.

The other day I came up with an idea that there was a counter pressure forcing the water in the tube to go down while the water in the tank remained high and eventually this mystical pressure caused it trip out on high limit. I metered the high limit during failure only to be proven wrong. But despite being told that my basic idea was scientifically impossible I found the smoking gun. Last night after posting this topic I finally found the supporting science to prove that water level can be high in the boiler while the sight glass level is lower and this eventually leads to a shutdown!!!

https://www.youtube.com/watch?v=a0xZPl_bwHI&feature=youtu.be

https://www.youtube.com/watch?v=tI3tWuSsX7c
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A malfunction at the junction

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#215042 - 02/24/15 08:34 AM Re: Have you ever had one of those jobs..... [Re: Potseal]
twh Offline
Member

Registered: 03/11/04
Posts: 892
Loc: Regina, Sask.
It's tripping out on a high temperature limit or high pressure?

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#215044 - 02/24/15 09:41 AM Re: Have you ever had one of those jobs..... [Re: Potseal]
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5299
Loc: Blue Collar Country
Oddly enough, I once encountered a similar problem with the water heater in a restaurant. The problem proved to be .... cardboard taped over a wall vent grill.

That's right. Even though the heater was located within feet of an open door, it was necessary for the vent to be unblocked for sufficient fresh air to reach the burner ... even though the vent was just as far away!

It appears that the vent was covered in the winter without causing problems- but, let summer come, and the combined draws of the cooking hoods and the air conditioning were able to starve the water heater.

Go figure.

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#215051 - 02/24/15 06:17 PM Re: Have you ever had one of those jobs..... [Re: Potseal]
LarryC Offline
Member

Registered: 07/05/04
Posts: 775
Loc: Winchester, NH, US
Great website for problems like this is www.heatinghelp.com

It is full of heating professionals who work on primarily water based systems like steam, various flavors of baseboard, and solar.

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#215056 - 02/24/15 09:47 PM Re: Have you ever had one of those jobs..... [Re: twh]
Potseal Offline
Member

Registered: 02/23/13
Posts: 187
Loc: Saskatchewan
Originally Posted By: twh
It's tripping out on a high temperature limit or high pressure?


It's tripping on LLCO.

But as I posted previously it's a far more complex situation that eventually leads up to that. So in order to come up with a solution we need to verify that what I now believe is happening is really happening and more importantly why is it happening.
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A malfunction at the junction

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#215057 - 02/24/15 09:51 PM Re: Have you ever had one of those jobs..... [Re: LarryC]
Potseal Offline
Member

Registered: 02/23/13
Posts: 187
Loc: Saskatchewan
Originally Posted By: LarryC
Great website for problems like this is www.heatinghelp.com

It is full of heating professionals who work on primarily water based systems like steam, various flavors of baseboard, and solar.


I have already attempted that but haven't received a response yet. Beyond that I talked to an acquaintance who teaches power engineering at a technical school. He wasn't too sure of what to make of it but at least he offered some suggestions that might help. It's a tough problem to describe in a short period of time. Would be better to have someone right there on site when it shuts down.


Edited by Potseal (02/24/15 09:53 PM)
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A malfunction at the junction

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