Why so tight - Magnafilter cap

[Mdljk]

Hello All,



My gas engineer did a first annual service in August. We've had new rads fitted and its time to add inhibitor and check the Greenstar Magnafilter. So I've added inhibitor through a rad and have isolated the magnafilter. Try as I might to remove the top of the filter to access the magnet for cleaning- using the supplied tool I could not. It was so tightly fitted that I feared stressing the boiler pipework any further. I therefore de-mounted it using the slip-rings and tried again. Kneeling on nice soft railway sleeper I applied all the torque I could muster but that cap would not shift. It came off easily in the first six months because I accessed it to add inhibitor and check for particles

Any idea HOW the gas fitter managed this or is it down to nature and pressure in the system.

Any advice on what to do to remove the cap so I can clean the element will be gratefully received.



Hi Everyone

As we all know there is one method to defeat stubborn fittings. I applied the 'Brute Force and Ignorance' approach and I got there - see photo. Any advise on how tightly to refit after cleaning?

Thanks

 

[ShaunCorbs]

Hand tite then just give it a nip 1/2 max

You can silicon grease the oring might help later on

 

[Harvest Fields]

They are always a bit stiff mate, especially if it is just screwed straight back in after cleaning. I find wipe the gap in between the lid and the base to remove all the moisture (it helps a lot).

 

[Mdljk]

Hand tite then just give it a nip 1/2 max

You can silicon grease the oring might help later on

Hi ShaunCorbs

sound advice as always. I'll pass that on to the service guy

 

[Mdljk]

They are always a bit stiff mate, especially if it is just screwed straight back in after cleaning. I find wipe the gap in between the lid and the base to remove all the moisture (it helps a lot).

Thanks Harvestfields - a good tip. No way this would have come out without bending 22mm pipes out of their fittings to the boiler. I have put it back hand tight then nipped it up maybe 1/8 turn with the huge plastic spanner. This one was beyond tight but the gas-service guy is great so thinking maybe heat/pressure but in all seriousness I think it was just over-enthusiasm on his part. Thanks

 

[Gasmk1]

I have found most are very tight but have always cleaned and added potable silicon to or o’ring and top of threads when i Reassembl, not always the engineer over tightening

 

[Mdljk]

I have found most are very tight but have always cleaned and added potable silicon to or o’ring and top of threads when i Reassembl, not always the engineer over tightening

Thanks Gasmk 1

I guess it must just be the 'heat over time' binding the plastic threads together'. Same thing happens with oil filters on cars which are also 'hand tight plus a half a turn'. Thing is you can give a car oil-filter some welly. On this occasion a de-mount from the system was essential. I think it would have been impossible to shift in-situ as the 22mm pipes into the boiler would have been strained. Having said that -even with the housing de-mounted - it took more welly than I could have imagined.

I dont have any potable silicon - but will try to source on-line. I imagine that Vaseline would 'gum-up' with heat over time.

Thanks for the tip

 

[Ric2013]

Doesn't have to be potable as you aren't drinking the water. You do need a silicone GREASE however as Vaseline (while it will not gum up) may harm rubber seals in the system.

 

[Mdljk]

Doesn't have to be potable as you aren't drinking the water. You do need a silicone GREASE however as Vaseline (while it will not gum up) may harm rubber seals in the system.

Thanks Ric203

I have some ordinary silicon grease so shall go with that.

 

[Chuck]

Try replacing the o-ring seal. Worcester sell a set of o-rings. A new one should/might allow the seal to make more easily with relatively little tightening. Supposed to be replaced every time but never is.

 

[Mdljk]

Try replacing the o-ring seal. Worcester sell a set of o-rings. A new one should/might allow the seal to make more easily with relatively little tightening. Supposed to be replaced every time but never is.

Hi Chuck

Interesting - will investigate further.

Thanks

 

[Gasmk1]

I only use potable because it’s clean, I have had to take off the manna clean one that’s like a football as i couldn’t undo it like you I didn’t want to break it.