test a boiler fan is working

[gregg1908]

Could someone explain the best way to test a boiler fan is working , IE resistance testing to see if the motor/coil is working

 

[armourer]

Just see if you are getting 240v at the fan on demand.

If you are and the fan does not run - Fan fault (using a volt stick is the easy option).
If your not getting voltage look elsewhere.

You can also get resistance check done by removing leads to the fan and test across the terminals.
A fault will show as open circuit or low resistance.


Another option would be to put the tube from your manometer on the Aps, call for heat and blow down the tube and make the aps.
This will fool the boiler into thinking the fan is running and if it fires up, as before check voltages to fan.

 

[stevetheplumber]

sucking and blowing aps is a no no youll most probably break ityou should use your multi meter to see if its switching

 

[armourer]

sucking and blowing aps is a no no youll most probably break ityou should use your multi meter to see if its switching

One of the tests I do is by sucking and blowing on the aps and use a multimeter to check n/o - n/c.
I have been doing it for years and never broke one yet.
I'm not a big puff you know!

Don't even bother to answer that. ;-)

 

[gasmarc]

like wise and i havnt broken APS either , you can usually tell if a fan is running by putting your ear to the casing , not when it is red hot , some makers tell you to test of the board but this can be a nightmare sometimes and something i rarely do , but the idea of removing a casing can be a pain also especially if it has never been removed since new

 

[SimonJohns]

Testing the newer modulating fans is a pain in the bum

On a worcester you have to check for 240 and if that's there the fan is broken




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[gasmarc]

i went to a job with 2 greenstars side by side and i felt a right muppet after spending over an hour trying to get either one of them to work on a sunday morning apparently an electrical spike took both fans out which bosch replaced foc even though the boilers were out of warranty ,strange . also the price of the fans use to be £180 bosch have since dropped the pri

 

[gregg1908]

I have the case off and the fan is not running,on demand the boiler goes straight to lockout with no fan start etc.

I checked resistance and there was none then i checked the fan connection from the pcb.

All of a sudden the fan worked and i got ignition leading me to a pcb interitent fault or loose wire.

Could i in future power up the fan using a direct 240v supply straight on to the fans spade fittings?

In therory the fan should be knackered as no resistance was detected but the fan has prooven and run now.

I removed the brown and blue wires from the fan and put a multimeter probe on each spade connector then set my ohms on 200 as the ferroli tech guy said the fans resistance was 76 ohms.

I recieved no resistance so it should be broke can anyone enlighten me please.

 

[SimonJohns]

When you say you checked resistance and you had none. Do you mean it was open circuit or do you mean that you had a closed circuit with no resistance


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[armourer]

I would look again at the wiring from the pcb to the fan.

No you cannot put a direct 240v supply to the fan as this would constitute modifying a gas appliance and is not allowed. Anyway the fan constantly running would be noisy and shorten the life of the fan also some boilers do a check at the aps before power is applied to the fan checking normally open and normally closed terminals.

 

[gregg1908]

Sorry i meant power the fan up to test it works not run it with a perminant live.

 

[gregg1908]

No resistance the meter did not show any reading

 

[armourer]

If you are getting no resistance ie: open circuit, then the fan is at fault.

 

[bill577]

If your multimeter showed a 1 that means your in the wrong range or open circuit, try going up or down the ranges until you get a reading, a dead short will show as 00.1 or as near as depending on the resistance of your leads and as the fan worked it means there was something wrong with your measuring or your meter (dying batteries perhaps)

 

[gregg1908]

Thanks i will try it again.

I am correct to presume i put one probe on each of the fans terminals and not cross them etc.

Im new to the multimeter as you can tell,we skirted its use in college only for the use of continuity and voltage etc.

I'm looking for a course that will make me more advanced in its use,i have just booked on a baxi one day boiler reapair course that will be a start.