Localized tightness test on boiler

[Matt0029]

Why is it is you carry out a localized tightness test on a boiler at the gas valve isolating at the boiler you get a drop. But not if you test the hole pipework? Is it because of the pipework volume is so small?

 

[Knappers]

Basically - yes.
A substantial drop on boiler would indicate a faulty valve.
Gas valves are allowed a small letby, that's why you can have a drop on test with appliances connected but not without.
The greater volume of gas the more buffering there is. This is also why we have different tightness tests for 35mm pipe and large meters.
And why finding small leaks on small bore pipes is such a ballache.

 

[Matt0029]

Thanks the tightness test on the whole installation was fine. But I just praticed a localized one on the boiler testing at the gas valve test point and isolating under the boiler and it dropped.

 

[Knappers]

If you've disturbed any joints then check with ldf but anything under 1mb in 30 sec is OK.
If over I'd check with manufacturer if gas valve requires replacement.
A test on gas valve isn't something I've ever done as a matter of course.
Does anyone?

 

[Matt0029]

I

If you've disturbed any joints then check with ldf but anything under 1mb in 30 sec is OK.
If over I'd check with manufacturer if gas valve requires replacement.
A test on gas valve isn't something I've ever done as a matter of course.
Does anyone?

I have an F62 fault on a vallient eco tech pro. I believe it's either the gas valve passing or the PCB. Not to check which

 

[ShaunCorbs]

Check resistance on coils should be higher than 150 if yes pcb

 

[Matt0029]

Check resistance on coils should be higher than 150 if yes

Thanks where on the gas valve do I test this? Is there 2 ports?

 

[ShaunCorbs]

On the leads connections that connect to the gas valve remove one and test on valve

 

[Matt0029]

Thank you. I hear it's mostly PCB F62? But I definitely want to confirm.

 

[Deleted member 120897]

Always been pcb for me, even without testing.

 

[Matt0029]

Thanks have you ever tried reconditioned pcbs ?

 

[Deleted member 120897]

Thanks have you ever tried reconditioned pcbs ?

No I haven’t, I’m employed and carry a van stock.

 

[Knappers]

Thanks have you ever tried reconditioned pcbs ?

I sometimes offer it as an option if the customer supplies the part but make it clear that I would have no responsibility for it.

 

[ShaunCorbs]

I would say no