Ulma 2000 tändfel

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Davey
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Inlägg: 3
Blev medlem: lör 16 jan, 2016 08:45

Ulma 2000 tändfel

Inlägg av Davey » mån 10 dec, 2018 20:34

Hope someone can help me! My swedish is not good, so will try in english.

The burner is from ca. 2007, sometimes when starting from complete cold, the fan only turns slowly and the pellets won't light. Switching on and off would cure the problem. So I thought maybe the fan was weak so replaced it.

But now sometimes I get tändfel when already running and the boiler reaches minimum temperature (65), so I guess it's the same thing happening, but when I am not there to witness it.

So I am wondering why this is happening as the fane seems to be fed directly from the plc, either high speed or low speed ( I am not sure how it decides fan speed).

Can anyone help me please?

Stegatorparn
Pannrumsmonster!!
Inlägg: 3684
Blev medlem: sön 22 jan, 2012 11:20
Ort: Kungsbacka

Re: Ulma 2000 tändfel

Inlägg av Stegatorparn » tis 11 dec, 2018 12:17

Hi Davey

I´m not so familiar with Ulma burners but I know some in general.
Did it help to change the fan? Does it work properly now?
When the fan is weak, the ignition element can be overheated. If it´s possible, check element resistance that should be around 137 ohms with an Ohm-meter if you have the old type of element. The new ceramic ones maybe have other specs. If you measure around 20% higher, it´s a good idea to replace it.
The Alarm message say that it´s some problem with the ignition element.

When the fan doesn´t work properly, the burner soothes and the flame detector could be dirty and misslead the PLC.
So check and clean the flame detector.
Senast redigerad av 1 Stegatorparn, redigerad totalt 0 gånger.
BioBjörn 18 -14, VB Combimax 2000 UB -94, Ulma doserskruv, ack Thermia SA500B, Thermomatic CBJ, 3 ton bulkförråd
Värmer 240m²(2pl) + 90 m² källare

Davey
Frö
Inlägg: 3
Blev medlem: lör 16 jan, 2016 08:45

Re: Ulma 2000 tändfel

Inlägg av Davey » tis 11 dec, 2018 20:14

Thanks for your answer!

No, the new fan makes no difference. I cleaned up the burner during summer and put in a new heater (it has a wire element like a heat pistol). I only use it at weekends which is how I discovered it sometimes starts from complete cold (10 degrees water temp) with slow fan speed. Turning off and on again and the fan turns at full speed, the pellets drop in for something like 70 seconds, and it fires up. So I am assuming that it sometimes has a tändfel during normal operation because it does the same thing, tries to start with low fan speed.

On first start up I assume it doesn't look for a flame, it just runs the start sequence, and at some point later it checks for flame, seems to be about after 3 minutes.

Just dont know why sometimes the PLC only runs fan at slow spped on start up. Industrial PLCs are usually pretty bulletproof, and usually fail to switch something, and not switch the wrong thing.

It may be the fan needs both high and slow connections energized to run high speed, and only the low connection is being energized because of a fault in the plc. I guess I can check that easily with a meter.

Stegatorparn
Pannrumsmonster!!
Inlägg: 3684
Blev medlem: sön 22 jan, 2012 11:20
Ort: Kungsbacka

Re: Ulma 2000 tändfel

Inlägg av Stegatorparn » ons 12 dec, 2018 09:13

There seems to be some problem with the PLC fan output.
Is it a relay output, maybe relay can be changed, but if it's a triac output, it can be trickier.
BioBjörn 18 -14, VB Combimax 2000 UB -94, Ulma doserskruv, ack Thermia SA500B, Thermomatic CBJ, 3 ton bulkförråd
Värmer 240m²(2pl) + 90 m² källare

Davey
Frö
Inlägg: 3
Blev medlem: lör 16 jan, 2016 08:45

Re: Ulma 2000 tändfel

Inlägg av Davey » ons 12 dec, 2018 15:49

Well I 'bit the bullet' and called Ulma direct.

The expert there said it is the fotomotstånd, as the PLC's never go wrong. He said if the start value is wrong (it should be zero) but I've watched it on startup and it goes up and down until the burner is properly alight. It certainly doesn't start at zero.

He said the PLC then won't know if its a cold start, or running, or if the heater needs to be kept on etc.

It kind of makes sense, so we will see of a new one fixes the problem.

Thank yo for your help.

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