cswd

We've just finished a fairly extensive retrofit (MVHR, ASHP, EWI, triple glazing etc) and had a final air tightness test. I was getting different advice from various locations about what to do with the MVHR when carrying out an air tightness test so, for reference, here's what Zehnder told me to do with our Zehnder Q450 ComfoAir: 'I can confirm you will need to block up the intake and exhaust, so cover the terminals with a material that will block airflow.' And in talking to them, they clarified that we were meant to block the external roof terminals. Unfortunately, I didn't have scaffolding up anymore, so couldn't get on the roof to block them. I hence followed the advice from the supplier (GBS) which was, roughly, 'cover the filters with plastic bags' (I used clingfilm). Zehnder stated they'll look into it and update their documentation & FAQs - given you'd think pretty much anyone fitting MVHR would end up doing an air tightness test seems daft that this info is hard to find! Does anyone have any better advice? I'm wondering if being unable to cover the external roof vents affected our final AT test (we got 1.77). Thanks, Stuart