Water filters and splattering taps!

[grahamr_5041507]

Our new van has a removable water filter fitted where the pump is plugged into the side of the van (why they bothered i dont know because who drinks the van water anyway? But thats another story...)

Trouble is, the plastic screw thread on the filter, allows air in and hampers the vacuum created by the pump. The van has got brilliant powerful mixer taps in it, but they are constantly hampered by the air entering the system and casuing major splattering problems.

I've taken the filter out, lubricated with veg, oil and tightend it as hard as i dare - with limited success.

Anyone have any ideas? Unfrotunately i cannot bypass the damn thing altogether.!!

 

[Damian]

Graham, I have heard of some problems with the plastic filters, mainly that they can crack around the screw part, whilst not completely breaking, it will allow air to be drawn in.

Assuming yours is not damaged in any way, I would use PTFE tape around the screw thread part, just a couple of turns, to take up any play in the joint, and seal any air gaps.

Take extreme care though, and only tighten enough to ensure a watertight fit.

 

[gary]

I take it's the Carver 'Crystal' filter system you have which is now made by Truma, there was two models which used the screw in filter. The mk1 with a fixed pump and mk2 with removable pump which is the one Truma now supply as the 'Truma Crystal'. If yours is the older Mk1 then I would suggest upgrading to the Mk2 using an adaptor plate.

With the Mk2 the first thing to check is the threads of the housing are not cracked and or distorted, if they are then it's very difficult to get a feel for the seal biting, so if they are I would replace the housing.

After that I alway use and recommend 'Silicone grease' as the lubricant, this is designed for the job, allows smooth turning and the seal to slip easily round as it contacts the housing, this way you will get a positive feel for when it is fully tight without fear of over tightening. Also it is still there doing a job when the time comes to remove the filter, unlike cooking oil!

To do the tightening I use a pair of standard pliers the wrong way round with the plier handles into the filter, this way the handles will lodge in the corners and give a firm grip without fear of breaking anything.

 

[grahamr_5041507]

Thanks for your help! I've tried the pfte option first of all - so simple cant believe i didnt think of that. I'm hoping it'll work beacuse the van is literally brand new.

I assume the silicon grease is food safe?

 

[gary]

I use Rocal 'aquasil' or RS Components own brand which is made by Dow Corning who of course make their own brand and for others, I have checked both companies CoSH sheets and found you could probably eat the stuff without harm!!

I would not recommend anything which may expand the threads, there is a design weakness at the 6 o'clock position in the housing threads which will crack very easily given half a chance

 

[grahamr_5041507]

Sadly the pfte sounded great but didn't work.

The broken vacuum is as bad as ever.

I'll tey the silicone and see how we go. I know lots of others have had more serious problems with new vans but it still seems rediculous that I'm tryin to work around a design fault!! Its been said before but you can buy a new car and they just work but vans,.....no chance!!

 

[gary]

Another thought, the 'o' ring seal on the pump connector could be the source of the air leak, are you then watching the air being drawn through the filter and assuming the filter is at fault?