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Hi,
Few days ago we had no hot water, and discovered that one of the safety switches on our hot water cylinder had popped up.
Pressed it back in, yet a few days later (having been away for a couple of days) the water's running cold again. Same thing with the safety switch.
Only just noticed that there are drops of water around the seal of the tundish. Not a lot, but looks to be a very slow leak.
Googled and read some horror story comments.
Tried to call installer but it's emergency number only now.
Any G3 qualified engineers lurking on here who can advise what level I should currently be panicking at?
Could just need a recharge on the expansion bubble. This "should" be something you can do yourself. My megaflow needs doing roughly annually.
I can't help with your problem, but it's interesting to hear the correct use of tundish.
My FiL (from the Black Country) uses tundish for "funnel".
Not sure about the "safety switch" - that might imply that something unsafe was happening
Failing that, I recharge the air gap in our megaflow when it starts to drip, as Sam U says
Any G3 qualified engineers lurking on here who can advise what level I should currently be panicking at?
Presumably you've turned off the HW now then?
If you're worried about some massive explosion, then you could always drain the thing while you wait for the engy.
Replenishing the air gap is easy, and worth a try. On my megaflo it's isolate the HW cylinder by turning off the cold supply, go downstairs and open the lowest hot tap - will gush then slow down, then head back up and find the pressure release valve and twist it to find the position where it remains open. Cue monster gurgling sound for about 10 mins. When it stops, and water stops coming out of the downstairs tap, reverse the three steps - PRV, Tap closed, Water supply back on.
The safety button sounds like the safety thermostat to me...
If your normal thermostat has frozen in, then the safety one will open to prevent overheat, but not (in my experience) before causing the relief valve to spill a little.
Although expansion vessel could also be low/punctured too.
Hi Jolsa, what make and model of cylinder? how is the water heated? boiler or immersion?
Thanks for the replies, does sound like the safety is kicking in due to overheating (problem with normal thermostat?).
And if that would explain the slight leak of water from the seal below the tundish then hopefully not a major issue.
Will see if the safety has kicked in again tomorrow morning (hot water set to be on overnight using Economy7).
In any case, I'll be looking to get a suitable Bristol engineer out to check it over next week.
Supremebean - it's a Dimplex SCxn150d, immersion.
Once again, thanks for the replies.
Yeah thermostat has packed in, causing the water to over expand and drip then thermal cut-out kicks in. Simple 5 minute job if engineer has a stat in his van.