HVAC Questions? Ask an HVAC Expert for Answers ASAP
Good morning, welcome to the Technical section in JustAnswer; my name is ***** ***** I will help you today.That's an automatic air vent. I'm not surprised that it started leaking after a drain and refill - that's what they're prone to doing. The cap is supposed to be loose, and can be closed off when needed, but your cap has clearly gone missing.The best you can do is wrap a towel around the pipe below the valve, to absorb the water, and drape the towel into a big bowl or bucket. The leak will probably slow overnight, and you can get a new AAV in the morning. The following product will probably go straight on in place of yours - if it looks different, then attach a photo of yours.AAV at ScrewfixYou don't need to drain again - just let all the pressure off and then water won't come out when you uncouple the old AAV._____If you receive a phone call offer, please ignore it - these are system generated and outside my control. My understanding is that you won't be charged if there's no phone call.
Do you mean the supply to the F&E cistern? There should not be a valve on the cold feed between the F&E cistern and where the makeup water enters the system. If there is a valve then it should not be closed when the boiler is running.