Advice on hot water cylinder

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Melti007

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#254409 11-Aug-2019 04:11

We woke up tonight with our hot water cylinder making lots of noises and water pouring down the street from our overflow pipe. We have switched the hot water cylinder off and the water mains off to the house till we can find out the problem.

There is a little black tap at the top of the cylinder coming from one of the pipes, it only turns half way on and off. Does anyone know what its for?

A towel had been put over the top of the cylinder last night to finish drying it and I wonder if this little tap has been hit my mistake. Could this be the problem? We are not sure what way the tap should be for on of off.

gregmcc

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#2293861 11-Aug-2019 06:55

is the water coming from the overflow hot?

if it is hot it will most likely be the thermostat failed on, if it's not hot then it will be a plumbing problem - either way get a professional

rogercruse

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#2293866 11-Aug-2019 08:00

Sorry to hear of your cylinder issues, but if you decide that a replacement cylinder is required, then:

get the biggest cylinder you can afford
Should you ever get solar panels then you'll be able to store more hot water.
look getting at the heat pump version
cheaper to run than a basic immersion heater
consider something that will give you better control than a simple timer or on /off switch.

We replaced our 180 litre tank with a 300 litre monster that was surprising looked no bigger. We still have plenty of hot water even in the middle of winter.

Our next major purchase will be a outdoor heat pump heater to further reduces the running costs and to reclaim cupboard space.

The better control is needed to capitalise on the deals available from the power companies. Plus you only heat water when the sun is shinning.

MadEngineer

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#2293881 11-Aug-2019 09:11

You're not on Atlantis anymore, Duncan Idaho.

MadEngineer

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#2293882 11-Aug-2019 09:16

Also: https://rheem.co.nz/assets/technical_documents/Installation-Guides/3cdef761bb/install-instruct-Rheem-electric-heavy-duty-122048-Rev-S-2018-August.pdf

MAINTENANCE REQUIREMENTS
MINOR MAINTENANCE EVERY SIX MONTHS
It is recommended minor maintenance be performed every six (6) months. Minor maintenance can be
performed by a responsible officer.
The minor maintenance includes:
 Operate the easing lever on the temperature pressure relief valve. It is very important you raise and lower
the lever gently. Refer to “Temperature Pressure Relief Valve” on page 8.
Warning: Exercise care to avoid any splashing of water, as water discharged from the drain line will
be hot. Stand clear of the drain line’s point of discharge when operating the valve’s lever.
 Operate the easing lever on the expansion control valve (if fitted). It is very important you raise and lower
the lever gently. Refer to “Expansion Control Valve” on page 8.
 Check the drain line from the safe tray (if one is installed) is not blocked.
MAJOR SERVICE EVERY FIVE YEARS
It is recommended a major service be conducted on the water heater every five (5) years.
Warning: Servicing of a water heater must only be carried out by qualified personnel. Phone Rheem
Service or their nearest Accredited Service Agent / Centre.
Note: The major service and routine replacement of any components, such as the anode and relief valve(s),
are not included in the Rheem warranty. A charge will be made for this work. Only genuine replacement parts
should be used on this water heater.
The major service includes the following actions:
 Replace the temperature pressure relief valve.
 Inspect and flush the expansion control valve (if fitted). If required, replace the valve.
 Inspect and if required, replace the anode.
If the anode is not replaced, it should be replaced within three (3) years of this service (refer to “Anode
Inspection and Replacement” on page 10).
 Check the electric heating units for excessive calcium build-up or corrosion and replace if necessary.
 Drain and flush the water heater if required.
In commercial applications where large volumes of hot water are used, sediment may build-up on the
bottom of the cylinder. In extreme cases, particularly in areas of high water sediment, draining and flushing
out may be necessary.
 Visually check the unit for any potential problems.
 Inspect all connections.
 Check the drain line from the safe tray (if one is installed) is not blocked.
Note: The water heater may need to be drained during this service. After the completion of the service, the
water heater will take some time to reheat the water. Depending upon the power supply connection, hot water
may not be available until the next day

You're not on Atlantis anymore, Duncan Idaho.

Bung

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#2293897 11-Aug-2019 10:21

A tap that does a partial turn seems more likely to be a ball valve than a lever operated relief valve. The only explanation for water ending up on the street I can think of is a roof top vent ending up in a stormwater pipe discharging into a street gutter.

Why a ball valve would be at the top of the cylinder is another question that would need the OP to comeback to the thread.

Scott3

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#2293899 11-Aug-2019 10:26

My guess will be that the thermal pressure relief valve will have failed open, and require replacement. Something you would be best to get a plumber to diagnose and action for you.

There likely is an isolation valve upstream of the entire hot water system (likely located near the cylinder), that will allow you shut of the flow of water, turn of the cylinder, and turn back on the mains. This will mean you can have cold water until the plumber appointment.

Melti007

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#2294150 11-Aug-2019 14:16

Thank you so much for all your advice, really appreciate it. Getting a plumber.