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OT: Not a smoke alarm

Started by Anthony William Sloman November 14, 2021
My wife got me out of bed this morning because our electric hot water tank was imitating a smoke alarm.

It was also projecting a rather fat spot of red light on the wall next to it.

It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water.

It took a few minutes  before I noticed that valve wasn't hooked up to mains electricity.

I then pulled at the black plastic cap on top of the device, which came off, revealing four AAA cells, at which point the penny dropped.

All of them read 1.27V on my trusty little voltmeter.

When I put in newer AAA cells (all of which read 1.57V or  1.56V) the beeping stopped and the flashing red spot of light went away.

The plumber who installed the new hot water tank (after the old one had leaked and wrecked a lot of carpet) hadn't said anything about the the water valve being battery powered. Irritating.

-- 
Bill Sloman, Sydney
On Sunday, November 14, 2021 at 2:29:56 PM UTC-8, bill....@ieee.org wrote:
> My wife got me out of bed this morning because our electric hot water tank was imitating a smoke alarm. > > It was also projecting a rather fat spot of red light on the wall next to it. > > It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water. > > It took a few minutes before I noticed that valve wasn't hooked up to mains electricity. > > I then pulled at the black plastic cap on top of the device, which came off, revealing four AAA cells, at which point the penny dropped. > > All of them read 1.27V on my trusty little voltmeter. > > When I put in newer AAA cells (all of which read 1.57V or 1.56V) the beeping stopped and the flashing red spot of light went away. > > The plumber who installed the new hot water tank (after the old one had leaked and wrecked a lot of carpet) hadn't said anything about the the water valve being battery powered. Irritating. > > -- > SNIPPERMAN, Sydney
Hey SNIPPERMAN, READ thy manuals rather than blaming the plumber (assuming that you CAN read!). Also, have a drain pan or equivalent under your hot water heater - they can, and DO, leak (fundamental basic home smarts).
Flypoop shits Again:

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> > > > It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed > > into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water.
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> > Hey SNIPPERMAN, READ thy manuals rather than blaming the plumber (assuming that you CAN read!). > Also, have a drain pan or equivalent under your hot water heater - they can, and DO, leak (fundamental basic home smarts).
** Reading is just not this Fly Poops's subject, ...... Phil
On 2021/11/14 2:29 p.m., Anthony William Sloman wrote:
> My wife got me out of bed this morning because our electric hot water tank was imitating a smoke alarm. > > It was also projecting a rather fat spot of red light on the wall next to it. > > It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water. > > It took a few minutes before I noticed that valve wasn't hooked up to mains electricity. > > I then pulled at the black plastic cap on top of the device, which came off, revealing four AAA cells, at which point the penny dropped. > > All of them read 1.27V on my trusty little voltmeter. > > When I put in newer AAA cells (all of which read 1.57V or 1.56V) the beeping stopped and the flashing red spot of light went away. > > The plumber who installed the new hot water tank (after the old one had leaked and wrecked a lot of carpet) hadn't said anything about the the water valve being battery powered. Irritating. >
At least your batteries hadn't leaked and destroyed the water hear electronics... http://www.flippers.com/battery.html Looks like I need to add water heaters to the list! What make and model is yours please? John ;-#)#
On Monday, November 15, 2021 at 3:44:05 PM UTC+11, Flyguy wrote:
> On Sunday, November 14, 2021 at 2:29:56 PM UTC-8, bill....@ieee.org wrote: > > My wife got me out of bed this morning because our electric hot water tank was imitating a smoke alarm. > > > > It was also projecting a rather fat spot of red light on the wall next to it. > > > > It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water. > > > > It took a few minutes before I noticed that valve wasn't hooked up to mains electricity. > > > > I then pulled at the black plastic cap on top of the device, which came off, revealing four AAA cells, at which point the penny dropped. > > > > All of them read 1.27V on my trusty little voltmeter. > > > > When I put in newer AAA cells (all of which read 1.57V or 1.56V) the beeping stopped and the flashing red spot of light went away. > > > > The plumber who installed the new hot water tank (after the old one had leaked and wrecked a lot of carpet) hadn't said anything about the the water valve being battery powered. Irritating. > > Hey Sloman, READ the manuals rather than blaming the plumber (assuming that you CAN read!).
The plumber left the manual for the hot water tank, and we went through it again this morning, trying to work out what was going on. The plumber didn't say anything about the valve, and certainly didn't leave a separate manual for it. I'd read the manual when we'd first got it, and the re-read was just belt and braces.
>Also, have a drain pan or equivalent under your hot water heater - they can, and DO, leak (fundamental basic home smarts).
The old hot water tank came with the flat (and may date back to 1986, when drain pans were less popular - if it had been replaced it would have been with like for like). Our story prompted a replacement in an adjacent flat, with catching tray and an identical cut-off valve. No manual for the valve showed up there either. -- Bill Sloman, Sydney
On Monday, November 15, 2021 at 6:50:28 PM UTC+11, John Robertson wrote:
> On 2021/11/14 2:29 p.m., Anthony William Sloman wrote: > > My wife got me out of bed this morning because our electric hot water tank was imitating a smoke alarm. > > > > It was also projecting a rather fat spot of red light on the wall next to it. > > > > It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water. > > > > It took a few minutes before I noticed that valve wasn't hooked up to mains electricity. > > > > I then pulled at the black plastic cap on top of the device, which came off, revealing four AAA cells, at which point the penny dropped. > > > > All of them read 1.27V on my trusty little voltmeter. > > > > When I put in newer AAA cells (all of which read 1.57V or 1.56V) the beeping stopped and the flashing red spot of light went away. > > > > The plumber who installed the new hot water tank (after the old one had leaked and wrecked a lot of carpet) hadn't said anything about the the water valve being battery powered. Irritating. > > > At least your batteries hadn't leaked and destroyed the water hear > electronics... > > http://www.flippers.com/battery.html
Happily they were dead boring zinc-alkaline Duracells.
> Looks like I need to add water heaters to the list! What make and model is yours please?
It's a Rheem Stellar - but you didn't read carefully enough. It wasn't the water tank or it's heater that created the problem, but a completely separate Evolve battery-powered water sensor and cut-off valve. What I'm pissed off about was that I wasn't told that it was completely separate. If I'd looked hard enough, I would have been able to work it out for myself, but who wants to contort themselves into the positions that let you look closely at what a plumber has squeezed into a cupboard? As it was I had to crawl around on the floor to work out what was going on, and replace the batteries. -- Bill Sloman, Sydney
On 15/11/2021 09:29, Anthony William Sloman wrote:
> My wife got me out of bed this morning because our electric hot water tank was imitating a smoke alarm. > > It was also projecting a rather fat spot of red light on the wall next to it. > > It wasn't actually the hot water tank, but the electrically driven water valve that shuts off the cold water feed into the hot water tank if the catching tray under the tank holds more than a centimetre depth of water. > > It took a few minutes before I noticed that valve wasn't hooked up to mains electricity. > > I then pulled at the black plastic cap on top of the device, which came off, revealing four AAA cells, at which point the penny dropped. > > All of them read 1.27V on my trusty little voltmeter. > > When I put in newer AAA cells (all of which read 1.57V or 1.56V) the beeping stopped and the flashing red spot of light went away. > > The plumber who installed the new hot water tank (after the old one had leaked and wrecked a lot of carpet) hadn't said anything about the the water valve being battery powered. Irritating. >
They could have used one of those batteries which are stored with dry electrolyte, and only get activated when they get wet. I found one once in a surplus radiosonde that I bought on eBay out of curiosity. The shelf life would be very long if it stays dry. Obviously you would have to install it in the pan, so that it gets wet when it is required to work. Finding a replacement might be difficult for consumers, but they likely require a new tank anyway at that point. There would be a problem if the user decides to tip in a jug of water to test the shut-off valve though, as those batteries fail quite soon after they are activated. They could have also use a normally-closed solenoid valve running from mains power. The coil power would be a significant waste though, which could be mitigated a bit if they could put it inside the thermal insulation so that the waste heat goes into the tank. Still it would mostly be a loss if the water would otherwise have been heated with a heat pump using a sixth of the electricity per unit of heat. The coil power could be reduced even more if it were only activated for a time after the tank pressure drops significantly, but the sensor for this might be expensive and the clicking could get annoying. One thing I have seen that might use a lot less electricity than a normally-closed solenoid valve is to use a spring-loaded valve opened using a gear train and small motor. I have some air conditioning damper servos that do this. An enormous spring closes the damper on power loss, and a tiny motor with very high ratio gearbox winds up the spring to allow the damper to move freely when the power is on. A second motor then controls the damper position when the spring is wound up and out of action.