Hi All,

I'm finally getting round to building a loop that I started 2 years ago! I bought a "ULTITUBE D5 150 PRO reservoir with D5 NEXT pump" and have been playing around with some potential loop design.

As it's my first time doing this, I thought I'd stop and check the first line I put in, which goes from a radiator to the inlet on the Ultitube.

So I put a plug into the outlet of the ultitube and attached a pressure testing pump to the radiator and it failed completely. All I got was a weird hissing / puffing noise.

I started testing sections of the loop and eventually tried just the Ultitube by iteslf and found the same hissing / puffing noise. Then I remembered the pressure equalisation membrance in the lid of the reservior and now I'm wondering if that is the problem?

Will it stop me pressure testnig the loop? Is there a way around it?

Thanks! Mike

Nevermind, I found my answer with the search tool! From another poster:

Thank you for contacting us! If your Ultitube came with a pre-installed D5 NEXT pump,
it must be the "PRO" version of the Ultitube. All PRO version
Ultitubes come with a pressure equalization membrane installed in the top lid
of the reservoir, so will not hold pressure by design.

If you want to pressure check your loop including the reservoir, you can try to
put some plastic foil between glass tube and lid of the reservoir or use this
lid without membrane: https://shop.aquacomputer.de/product_inf…roducts_id=3865

True. I just hit copy and paste from someone else’s post. The lid is available on the website, but not with delivery to the UK. Another website has them so that may be an option. I’d rather the kid without the membrane be provided with the reservoir as pressure testing is something I’d like to be able to do.

Here’s a link that works

https://shop.aquacomputer.de/product_inf…roducts_id=3865

As an update, I bought the lid without the membrane from a UK store. Worked well for pressure testing and I’ve just kept it on now the system is up and running