Blower continues working although OFF3-Mode

[FMRathmanner]

Hello everybody,

i hope somebody can help me with the following problem.

A friend of us is using the 4.99 Scotte Controller. The Controller is operated via an external Control. If the Scotte Control goes in OFF3-Mode, the blower continues working....all the time.

Does anybody know why this could be?

Thanks for your help,
Sandra

[Martin Pedersen]

Hi Sandra

I cant say I know the v4.99, but I can say that if the blower is supposed to be turned off in that mode, it's probably the output that's burned out. You should be able to solder a new component on the print, for a very small amount of money...

I would open the box, and check the components...

[danskfocus]

Martin, would you be able to pinpoint the output components for a certain channel, on a picture ?.

I have a similar problem, but can not see any obvious damage to components on the print.

[Martin Pedersen]

Probably... or possibly someone else can.

[FMRathmanner]

It is not the relais or the pins.

[Martin Pedersen]

Maybe the chip isn't seated properly, or the chip has a blown output?

[FMRathmanner]

Hi Martin,

we checked the chip as well as the correct position of the chip......but everything is ok with it.

[Martin Pedersen]

Hi Martin,

we checked the chip as well as the correct position of the chip......but everything is ok with it.

I don't know about the OFF3-Mode... was this something you had working at some point, and did it just start to fail?
I don't know the print. Can you provide a image? If the output has a thyristor on it, I would check if there is a measurable power output to the gate from the chip... if there is not, and you can measure power on the output, I am quite sure it's the thyristor that's broken.

[FMRathmanner]

Hi Martin,

you know, actually we know a lot about heating system controls. our company is in heating systems and controlling business for 20 years. we are programming and developing complex heating systems. concerning failures, we have seen many of them as well as solved quite a lot. the differnece between our and scotte systems is, that we have(here in austria)  for the different heating systems and their control units, manuals, electronic circuit diagramms, data sheets and so on. that makes it much easier for us to find the mistakes.
in the described case(above) it would be much easier with the help of a electronic circuit diagramm to measure the voltage and find the mistake.
Since there is no written informaton, we work many hour on solving the problem. if we would charge our customer with it, they would loose a lot of money.


that's why we hope to get some help here, to find a person, who might got the same problem and figured out a solution by now.

in this particular case, the control system is working perfectely, if the 2 external inputs are bypassed via a bridge(connecting the 2 inputs with a wire).
the problem shows up, as soon as the burner gets start or stopped with the external control. As soon as the burner gets stopped, the blower continues working.

[Martin Pedersen]

Hi Sandra

I'm just trying to understand your problem. You want to control when the pellet burner is running,
so you have connected your stuff to the external ports.

You should be able to control if the burner is on or off with those two external pins.
If you short circuit the pins, the burner is ON.
If you break the circuit, the burner is OFF.

If the blower continues to run after the shutdown period, then something is broken.
You haven't by accident dumped voltage in on those two ports?

If you leave the two pins short circuited, so the burner is running, and manually shutdown the pellet burner by holding down the down arrow for a period, does the pellet burner then shut down, and stop the blower... or does it continue to blow?

To me it sounds like you have a malfunction...
If it stops the blower on a manual shutdown, then it's the chip that's broken.
If the blower continues to run when manual shutdown, then I think the thyristor is broken.

OFF3 means that it's off by external control. OFF2 means manual off...

Try and give as much detail on your answers as possible. Then it's much easier to help you

[FMRathmanner]

Hello Martin,

first of all, thank you very much for your time and help.

No, we did not accidentely dumped voltage on those two ports. Both ports are without voltage. They are potential free contact.

If we shut down the pellet burner manually, the burner shut down and the blower stopps.

The chip is ok and the thyristor also. The chip is the 4.99R.
We have some heating systems using the 4.99R but they are working without problems.

The blower continues working only when OFF3 Mode.

Thank you Sandra

[Martin Pedersen]

first of all, thank you very much for your time and help.

No, we did not accidentely dumped voltage on those two ports. Both ports are without voltage. They are potential free contact.

Just checking And, you are quite welcome.

If we shut down the pellet burner manually, the burner shut down and the blower stopps.

The chip is ok and the thyristor also. The chip is the 4.99R.
We have some heating systems using the 4.99R but they are working without problems.

The blower continues working only when OFF3 Mode.

Logic dictates that it's the chip that's faulty, since it is asking the blower to continue blowing while in OFF3 mode.

I think I heard some time ago that there was sub builds of the same version, so there could be small differences between two with the same version number. Have you tried with another chip of the same version..? Just to verify if the problem goes away, or stays?