Ideal Classic FF250 help needed

[Stevie100]

Disaster... me again!

Unfortunately it hasn't worked

I installed the new PCB and the first thing I noticed was that when I switched it on, there were two clicks from the relays - on the old PCB there was only one click (from the right-side relay) when switching on.

But the boiler still didn't burst into life with the new PCB, so I removed the fan Molex, and as I pulled at it, it made a vital connection and the fan and burners started to work. Thinking this bad connection was the problem I switched it off and sorted out that molex so the connection was good.

On switching on again, no joy, and this time only ONE relay clicked.

On closer inspection, the left relay is charred. I don't know if it was charred already (it's a used PCB). On looking at the old board, the relay is also charred on that one.
http://www.hpjw.co.uk/temp/charring.htm

So:
1) Is this charring normal?
If not
2) What does this relay do?
...and therefore
3) What could be causing the relay to burn out?

Help!
Steve

 

[geoff@cetltd]

Disaster... me again!

Unfortunately it hasn't worked

I installed the new PCB and the first thing I noticed was that when I switched it on, there were two clicks from the relays - on the old PCB there was only one click (from the right-side relay) when switching on.

But the boiler still didn't burst into life with the new PCB, so I removed the fan Molex, and as I pulled at it, it made a vital connection and the fan and burners started to work. Thinking this bad connection was the problem I switched it off and sorted out that molex so the connection was good.

On switching on again, no joy, and this time only ONE relay clicked.

On closer inspection, the left relay is charred. I don't know if it was charred already (it's a used PCB). On looking at the old board, the relay is also charred on that one.
http://www.hpjw.co.uk/temp/charring.htm

So:
1) Is this charring normal?
If not
2) What does this relay do?
...and therefore
3) What could be causing the relay to burn out?

Help!
Steve

I explained about the fan relay and told you where to look

 

[Stevie100]

I explained about the fan relay and told you where to look

Help me out here... Told me where to look for what?

 

[Agile]

It seems that you have wasted £28 on a faulty pcb.

I wonder why it was being sold? I would sell you a used one for £10 and will guarantee that it does not work!

If you can get a repaired one for £25 including postage and VAT and a guarantee, then you should jump at it ! Makes you wonder how they can do it !

Tony

 

[Stevie100]

It seems that you have wasted £28 on a faulty pcb.
Tony

I think it was my boiler that blew the new PCB, in the same way it caused the original to fail? There were definitely two relay clicks to start with.

 

[Agile]

What has actually failed on the PCB ?

Have you measured the resistance and inductance of the fan?

Or powered the fan from an independent source?

Tony

 

[Stevie100]

What has actually failed on the PCB ?

Have you measured the resistance and inductance of the fan?

Or powered the fan from an independent source?

Tony

The left relay (apparently the fan relay) is charred. I'm assuming it's that which has failed

How do I measure the resistance and inductance of the fan? I have a standard digital multimeter which does resistance. But how do I measure inductance?

No I haven't independently powered the fan. Is this as simple as connecting 240v to the fan molex? What size fuse would I put in the supply?

ta
Steve

 

[ChrisR]

They're usually around 50 Ohms.

Beyond that, be careful, and you may not be able to measure much because you won't have the kit a 'boiler engineer' would use.

Measure Fan connector at the board end, disconnected, to earth as well on a high Ohms scale, though mains may "see" a conductance your meter doesn't. Needs a high voltage tester really.

Fiddling about with mains on the molex could be inviting an accident unless you have a lead made up to plug into it. The connectors on the fan itself are liable to be fragile, if you just pull them off you'll probably wreck the fan.

There's absolutely no point suggesting you measure inductance, because if you had the specalist meter required you'd know how to use it....!

 

[Stevie100]

They're usually around 50 Ohms.

Beyond that, be careful, and you may not be able to measure much because you won't have the kit a 'boiler engineer' would use.

Measure Fan connector at the board end, disconnected, to earth as well on a high Ohms scale, though mains may "see" a conductance your meter doesn't. Needs a high voltage tester really.

Fiddling about with mains on the molex could be inviting an accident unless you have a lead made up to plug into it. The connectors on the fan itself are liable to be fragile, if you just pull them off you'll probably wreck the fan.

There's absolutely no point suggesting you measure inductance, because if you had the specalist meter required you'd know how to use it....!

So what do you think I should do?
1) I can measure Ohms of the fan at the board end (should be around 50)
2) I'm happy(ish!) to attach 240v to the fan molex and see what happens

Should I just replace the fan? Is this definitely the problem?

I can fix the fan relay on the board (each board has two relays and they look exactly the same. I can take the remaining good relay off the other board once I've solved what makes the relay blow in the first place)

 

[BDL]

I have read this topic and I can only say Scary stuff.

Are you trying to save money? The Classic is probably the easiset/most reliable boiler that was ever produced by Ideal Boilers.

The relay that you are talking about becomes charred(well actually just blackens the plastic) during normal use. This is made worse if the boiler from which it comes from has been cycling on and off.

Most Classics I have ever seen have a blackened relay case!!

Remove the thermister molex from the pcb (2 black wires middle left of pcb, leave them disconnected and turn on. The boiler fires yes?

If so, go and buy a new thermister.

 

[Stevie100]

I have read this topic and I can only say Scary stuff.

Are you trying to save money?

Most Classics I have ever seen have a blackened relay case!!

Remove the thermister molex from the pcb (2 black wires middle left of pcb, leave them disconnected and turn on. The boiler fires yes?

If so, go and buy a new thermister.

Ah, great. I wondered if the relay on the 'new' PCB was blackened beforehand - I didn't check. So that may be a red herring?

I'll try the thermistor test tonight when I get home.

(Of course I'm trying to save money! I don't pay people to do jobs I can do myself (it remains to be seen whether I can do this myself!))

 

[Stevie100]

OK. progress...

I removed the thermister (thermostat?) molex and nothing happened.

So, following p37 on here:
http://www.idealboilers.com/docs/html/classic_se_ff_manual.html
that took me to:
the fuse?: It's OK
then:
Is there a live supply on the violet lead to pressure switch? Yes there's 240v between the violet and earth.
then:
Is there a live supply on the red lead to the pressure switch? No!!!!!

So therefore I'm at: Check connections and leads to pressure switch. If no fault found change pressure switch.

So now my question is where do I get a pressure switch from. Either in Nottingham or mail order?

Cheers for the help.
Steve

 

[ChrisR]

So what do you think I should do?
1) I can measure Ohms of the fan at the board end (should be around 50)
2) I'm happy(ish!) to attach 240v to the fan molex and see what happens

Should I just replace the fan? Is this definitely the problem?

How the heck can I say from here - told you how to test the bloody thing!

For parts - google.

By the way - as you know you're looking at the manual for a different boiler. However I have checked and this part is the same for the right one.

 

[Stevie100]

[How the heck can I say from here - told you how to test the b****y thing!

Are you talking here about the fan or the Air Pressure Switch?

The fan resistance was exactly 50 Ohms as you predicted. I didn't get as far as connecting 240v to it as I then found the air pressure switch problem.

[By the way - as you know you're looking at the manual for a different boiler. However I have checked and this part is the same for the right one.

Again, do you mean the fan or the APS?

 

[Tuscan_Den]

I have an identical problem on my Ideal Classic FF250
So I am interested to hear what progress you have made.

ChrisR, do you have the correct manual for this boiler ?

Cheers

Den