L
Leoki
Good morning, i have a multi part question if you have a moment to read and possibly comment.
I have just replaced the immersion heater on a copper cylinder but i had some problems isolating the cold supply. There is a gate valve which i shut and then using a hose pipe i opened the drain cock at the base of the cylinder and water started to drain away however when i started to unscrew the old unit (i did wait about 20 minutes first to allow enough water to drain) water was trickling out so there was water still feeding into the cylinder. I put this down to the gate valve just not closing fully so i then turned off the stopcock, the property is a direct feed but the cylinder still appeared to be filling albeit it slowly. I got the immersion swapped over but the water level in the tank never actually went down more then 3/4 volume.
Now that the immersion bit is fixed the customer has reported the cylinder is leaking from the bottom blanking plug (whoever installed the cylinder used an indirect cylinder so the flow and return are blanked off) so i need to drain the cylinder again and to be able to get the blanking plug off so i can re-seal it.
If the gate valve and the properties stopcock are not stopping the cylinder filling up, am i missing something. I have had a good look around and there do not appear to be any more taps or valves with which i can isolate the supply.
Also being a copper cylinder heated by an immersion, what happens with expansion ?. The new immersion has a thermal cut out (BACKERSAFE) but what happens if that was to fail and the water gets too hot, where would the water expand too, there is no water tank.