Ideal he30 L-F fault

[ihateplumbers]

Hi, I have an Ideal HE30 which is displaying the L-F fault. I have measured only 110v dc at the gas valve(instead of 200v i believe) and there is no voltage going to the igniter module except for near the end of the sequence when 200v flashes up for about a second.

The boiler goes through its starting up procedure with the pump running,the top fan running etc and the circuit board can be heard making all sorts of clicking relay noises.The board is the orange type.
I have checked the resistance of the thermisters and they seem to be reading ok.

The only other thing is the ignition module.I cannot get any resistance across the input terminals.Is this correct or does this mean its goosed?

My hunch is that's its the circuit board that's causing it but have any of you guys any ideas as to other checks i can do before ordering a replacement.

Thanks for your help.
Regards.

 

[AGAS]

well your hunch is wrong and get a gas engineer out as you shouldn't be within the boiler

 

[Steelmasons]

Crack on..

 

[Agile]

Did you measure your 110 vdc with an oscilloscope?

 

[ollski]

You could check your condensate pipe isnt blocked at the outlet end I guess but there are at least 4 more likely reasons for ignition lockout that really do need a semi skilled boiler monkey to check.

 

[ihateplumbers]

Did you measure your 110 vdc with an oscilloscope?

No just a multimeter.According to the ideal flowchart at says to measure the voltage at the pins of the gas valve and if there's not at least 150v or more then change the pcb.I have read on here with someone with a similar fault to mine where they had 110vdc at the gas valve and it turned out to be the pcb.

 

[Agile]

Many gas valves are supplied with raw DC. Do you know what that means?

Different meters display varying amounts in this case. Often from 50% to 150% of the true effective value!

It is possible to make up a simple circuit to correct the reading but for most its easier to measure raw DC and calculate a correction value.

Better quality meters like Fluke usually respond better when measuring raw DC.

Tony

 

[Agile]

Cheaper meters usually respond badly when measuring raw DC.

Tony

 

[AGAS]

No just a multimeter.According to the ideal flowchart at says to measure the voltage at the pins of the gas valve and if there's not at least 150v or more then change the pcb.I have read on here with someone with a similar fault to mine where they had 110vdc at the gas valve and it turned out to be the pcb.

go on then change it then

 

[mcmoby69]

go on then change it then

What the boiler?

 

[bernardgreen]

measure the voltage at the pins of the gas valve and if there's not at least 150v or more then change the pcb.

Does the flow chart also suggest measuring the resistance between the pins of the gas valve ( when disconnected from the PCB ) and ensure it is within a few percent of a value given in the fault finding instructions ? Low voltage could be the result of shorted turns in the gas valve solenoid. This causes more current to flow, the PCB may be current limiting or may be damaged by the excess current. There is a risk of a faulty solenoid damaging a replacement PCB.

Many gas valves are supplied with raw DC

RAW DC..... I so dislike that description. DC derived from rectified AC can be unsmoothed and / or unregulated DC but not "raw".

 

[AGAS]

Does the flow chart also suggest measuring the resistance between the pins of the gas valve ( when disconnected from the PCB ) and ensure it is within a few percent of a value given in the fault finding instructions ? Low voltage could be the result of shorted turns in the gas valve solenoid. This causes more current to flow, the PCB may be current limiting or may be damaged by the excess current. There is a risk of a faulty solenoid damaging a replacement PCB.

your not helping the op , to help you need to know how a boiler works

 

[bernardgreen]

your not helping the op , to help you need to know how a boiler works

It is not necessary to know how a boiler works to know how to verify the reason for low voltage on a solenoid coil.

really do need a semi skilled boiler monkey to check.

Maybe if some of these semi skilled boiler monkey were given a basic introduction to fault finding on electrical equipment (*) fewer owners would be paying large sums of money for un-necessary new parts.

(*) solenoids with shorted turns are not repaired by fitting a new PCB
three new PCBs fitted in a year before the manufacturer became involved and diagnosed a fault on the fan that was destroying the fan speed control on the PCB


EDIT I am aware that some sometimes a solenoid can be pulled in with a certain voltage and then held in by a ( much ) lower voltage.

 

[ollski]

Maybe if some of these semi skilled boiler monkey were given a basic introduction to fault finding on electrical equipment (*) fewer owners would be paying large sums of money for un-necessary new parts.

As far as I'm aware the op hasn't called in anyone or paid anyone. I really couldn't care less what anyone does personally but there are very important checks this boiler needs which won't be diagnosed with a multimeter.

 

[ianmcd]

Did you measure your 110 vdc with an oscilloscope?

Come on Tony you are now telling us you have an oscilloscope that you take to jobs in your backpack on the bus and tube you are so full of absolute shoite, non of the time served Proper tradesmen on here would ever need an oscilloscope to diagnose the fault on this boiler, you and Bernard are an absolute joke on here the sad thing is most posters in this section are looking for help and you two just spout absolute drivel