We had a gas safety check last week and now we just tried to turn our heating on - it's not working, the boiler gives an error message. (0 then 3 horizontal lines).
Boiler type is Ideal Isar HE30 and there's a Fernox TF1 magnetic filter connected to it. We noticed that the gas engineer left the little red valve open (vertical) above the filter, but the other one below the filter is in horizontal position (closed). We think that that is what causes the issue. Is it safe to open that other valve so both would be in vertical position? (The boiler passed the safety test btw; everything was OK with it; we think the tradesperson just forgot to open that bottom valve, but we can't get hold of him to ask.) Any advice from qualified heating engineers is very appreciated. Thanks!
