I had installed a new 35L low pressure Rheem hot water cylinder. My overflow pipe (on the roof) now drips cold water intermittently. It is not a lot of water, but my old one never did this. It also only seems to do it in the afternoon and then stops. We shower in the morning. The plumber told me that the new Rheem hot water cylinders to do this after heating the water up again. It is letting off pressure. The pressure and valve (under the house) are fine. Does this sound correct?
dee238,
Nov 29, 5:02pm
Sorry forgot to add the water dripping is cold, not hot.
lythande1,
Nov 29, 6:48pm
35l? Or 135l?
Probably a faulty valve. If that's what the plumber said, get a new one.
jonners2013,
Nov 29, 7:58pm
must be quick showers!
trad,
Nov 29, 8:24pm
My guess is that the pressure needs to be slightly reduced at the Nefa or Ajax valve (or a new washer put in) so that the standing head of water in the overflow pipe is reduced. Presume the water overflow is so slow that the hot water has cooled by the time you tested it's temperature.
shakespeare6,
Nov 30, 12:08am
You are going to get a certain amount of drip when it's heating due to expansion. Your cylinder will expel at least a couple of litres a day while heating. A good test is when it starts to drip flick the switch off and see if the dripping stops. That confirms thermal expansion. When the Ajax valve is first set up the plumber will adjust it till the level in the over flow pipe will sit just below the top. Your old cylinder may have been adjusted less so you did not see as much expansion. don't go messing with valves etc most people don't even understand how the system actually works. Leave it to a plumber to check. these days normally they are valve vented where they have a cold water expansion valve fitted just above the Ajax and below the bottom of cylinder so when heating the expanding hot water just push out unheated cold. - they also have a hot water expansion valve on the top of the cylinder which is set slightly higher than the cold.
dee238,
Nov 30, 3:10am
It was 135L. The plumber checked the valve and said the pressure and washer were fine.
Shakespeare6 - thanks for the feedback. One thing - when you say flick the switch off - which switch do you mean? Sorry to be clueless - that's why I came on here.
tintop,
Nov 30, 6:16am
At the cylinder there should be a flexible conduit connecting the cylinder to a wired in power outlet box with a switch.
Either that one - or there will be a circuit breaker or switch and fuse on your distribution board labeled 'HW' or similar
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