Ideal isar 30he

[GazDagasMan]

Hi, im currently working on an ideal isar 30he and im finding it a bloody nightmare.
Step 1: Turn boiler on, ask for heating and the fan runs
Step 2: gas valve opens and the boiler ignites
Then within a 10 seconds the boiler starts to humm and shake, gas cuts out and it re does the procedure above 3-4 times and then cuts out with an l-f fault.
the boiler has a new orange pcb fitted, condensate traps are completely clean and so is the trap. sump is completely clean, fan is not making any weird noises, flue is clear, electrodes have continuity when checked with meter and gaps are fine.
I rang ideal and they were no help what soever, they told me it could be the gas valve. so i wanted to know if any1 else has experienced this sort of problem. all help will be appricated, and if i find the problem with it i'll post it up to help others

 

[crashndie]

whats the gas working pressure at the boiler? had some think similar my self. it turned out the boiler was undersized, had 22mm on show an 15 mm under the floor

 

[Garfeild]

Check inlet working pressure,sounds like it could be low.Check flue if its a new install.

 

[GazDagasMan]

Gas supply is 22mm from the gas meter, it is in a new block of flats. this is the weird thing, i put my u-gauge on the gas inlet side and turned the gas on slowly (hoping it would give me a working pressure) i neva seen the water in my u gauge shoot out the otherside so quickly. i was thinking that the governor on the meter could be stuck and not regulating the pressure, but im not sure. FLUE i took the flue off and tried to run it and i got the same problem. iv got to go there tommorrow and fix it so im desperate to sort it out, iv got a gas valve in the van. thank you for your quick replys

 

[Garfeild]

You need to have your gauge on the inlet when the boiler is lighting see what it drops to,isars will run ok on pressures as low as 14 mb,if it gets much lower,(poss faulty governer) they make a hooting,rasberry blowing noise,and will cut out,and go to LF.

 

[crashndie]

all tho they will run at 14mb there still subject to a b.s standard staying they must have 20mb working pressure its in the manufacture instructions, as garfiled said they usually go to LF. worth checking at the boiler and at the meter,

wen the boiler is fired dos the flow pipe get hot is it pusshing water round?

 

[BOB D.O.L.E]

Gas supply is 22mm from the gas meter, it is in a new block of flats. this is the weird thing, i put my u-gauge on the gas inlet side and turned the gas on slowly (hoping it would give me a working pressure) i neva seen the water in my u gauge shoot out the otherside so quickly. i was thinking that the governor on the meter could be stuck and not regulating the pressure, but im not sure. FLUE i took the flue off and tried to run it and i got the same problem. iv got to go there tommorrow and fix it so im desperate to sort it out, iv got a gas valve in the van. thank you for your quick replys

i think the clue to this one is

i put my u-gauge on the gas inlet side and turned the gas on slowly (hoping it would give me a working pressure) i neva seen the water in my u gauge shoot out the otherside so quickly

 

[BOB D.O.L.E]

Gas supply is 22mm from the gas meter, it is in a new block of flats. this is the weird thing, i put my u-gauge on the gas inlet side and turned the gas on slowly (hoping it would give me a working pressure) i neva seen the water in my u gauge shoot out the otherside so quickly. i was thinking that the governor on the meter could be stuck and not regulating the pressure, but im not sure. FLUE i took the flue off and tried to run it and i got the same problem. iv got to go there tommorrow and fix it so im desperate to sort it out, iv got a gas valve in the van. thank you for your quick replys

i think the clue to this one is

i put my u-gauge on the gas inlet side and turned the gas on slowly (hoping it would give me a working pressure) i neva seen the water in my u gauge shoot out the otherside so quickly

is there a gas cooker in de house if so whats the working pressure at the meter. this is a way of testing the meter gov if it does the same as the boiler and shoots out i would be looking at the meter gov.

 

[GazDagasMan]

Thank You for the replys, i will check the meter gov. worst thing is the boiler is the only gas appliance in the place. i may just call Emergency and get them to change it while im there. ill let u all knw what happens 2moro

 

[GazDagasMan]

Turned upto the job today and its all working, govner was the problem, it had siezed due to the cold weather and was not regulating the pressure, i.e the gas pressure was way too high.
called gas boar to come and change it

Thank you for your help

Dont buy Ideal, load of rubbish according to my merchants, none of them are any good and only last about 6 months before problems start happening

 

[Garfeild]

Turned upto the job today and its all working, govner was the problem, it had siezed due to the cold weather and was not regulating the pressure, i.e the gas pressure was way too high.
called gas boar to come and change it

Thank you for your help

Dont buy Ideal, load of rubbish according to my merchants, none of them are any good and only last about 6 months before problems start happening

So the meter governer was the boilers fault?

 

[mcmarshon]

So can anyone explain the humming & rattling ?

Surely its the gas valves job to entrain the correct amount of gas, so regardless of the inlet pressure it should regulate the amount getting to the burner ?

Does that make sense ?

 

[davebgas]

Pressure was to high at the govenor? What was the standing pressure and did it drop low on ignition?

 

[crashndie]

humming an rattling nose will be gas lift of the burner, the gas vale will regulate from max 23 mb working pressure an regulate what the boiler needs. but the gas meter governer will drop down from 75mb coming in to the house down to 23mb max. so the pressure coming in to the building is pushing passed what the gas valve can handle.

 

[davebgas]

but the gas meter governer will drop down from 75mb coming in to the house

Not on your life will it....
Even though Low pressure is up to 75mb you won't find a LP network running at 75mb... unless the district govenor has failed. Its too high and increases network shrinkage costs.
Highest LP system I ever set up for for 50mb with a monitor setting of 55mb, and that was during winter on a high demand network.