DIY Doctor UK DIY Forums

Hi everyone,

Hoping someone can answer a question that's been frying my noggin. I won't bore you with reasons for asking, but what I wanted to know is:
I have a open vent system (F/E and CWS in loft) and h/w cylinder in airing cupboard. I know the cylinder has a vent/ expansion pipe that goes into the loft, along the loft floor and up and over and into the CWS tank. I know water level in this pipe will be same as water level in CWS tank. Question is, when the hot water in cylinder is being heated, does the water in this expansion / vent pipe also get hot, so would steam come out of the end of the expansion/vent pipe (into the CWS tank)? Or does the water in the expansion pipe stay cold? Thank you in advance

hello

your cws tank should be cold the vent pipe will get warm as you heat your hot water. Is your hot water getting very hot?

GayEddie wrote:hello

your cws tank should be cold the vent pipe will get warm as you heat your hot water. Is your hot water getting very hot?

Thanks for coming back to me Eddie. Yes, the hot water is hot, and I think the cold water in the tank is cold. In a nutshell, trying to see if any significant amount of steam would be escaping via the vent pipe (trying to get to the bottom of a moisture source in the loft) and just ruling out obvious possibilities. Appreciate any steam would end up in the tank, so its a long shot, and I have had the heating on for three hours and had a look at the vent pipe and no steam was visible coming out. As I say a long shot! Thank you for taking the time to reply, much appreciated.