Water Heater Anode Rod Replacement: Match the Length and Gasket

The element is out, the tank is part-drained, and the old flange gasket has set flat against the steel. For a water heater anode rod replacement on an electric storage hot water unit, two parts usually decide whether it is a one-visit job: the magnesium anode rod and the gasket that reseals the element flange. Here is how to match both before the tank is opened.

What the Anode Rod Does in a Hot Water Unit

The anode rod is a magnesium rod fitted inside an electric storage hot water system to protect the tank from corrosion. The Cabac rod covered below is described on its product page as corrosion protection that helps extend the lifespan of hot water tanks, for residential and commercial hot water systems.

Because it protects the tank instead of heating the water, it is easy to leave off a service checklist. The parts list for the job is short: the right rod, and a gasket if the element flange is being opened. Follow the unit manufacturer's service instructions for when the rod should be replaced. Water heater, hot water system and hot water unit all describe the same job here, and the parts are the same whichever term your customer uses.

Matching the Anode Rod: Listed Length and Your Unit

The Cabac 1510mm magnesium anode rod is listed for Dux and Rheem hot water systems. The listed dimensions are 20mm x 1510mm x 20mm, it weighs 1.5 kg and it is supplied as one piece.

The listing also describes the 1510mm length as suitable for specific hot water models, so the brand name is only a starting point. When you are sourcing an anode rod for a water heater, read the model details off the unit's data plate and compare the length of the old rod with the listed 1510mm before you order.

Delivery is worth sorting out early on a long item. The rod's product page shows free pick-up for items over 25 kg or over 1 metre and says to contact SCHNAP for delivery cost. If the job is urgent because the customer has no hot water, contact SCHNAP about the rod first, and check the same-day delivery cut-off times and charges for Sydney orders.

Hot Water Element Replacement: Reseal the Flange

If the element comes out during the service, the flange needs a gasket when it goes back in. The Cabac element gasket is listed as a silicone rubber replacement gasket for 4 bolt flange Rheem hot water elements. Its listed dimensions are 5mm x 100mm x 100mm, and it is listed for hard-water use. The product page recommends installation by a qualified technician to ensure proper sealing.

Lay the old gasket against the new one and compare the outline and bolt pattern before you refit. The listing covers 4 bolt flange elements only, so if your flange is a different type, this is not the part.

The gasket does not stand in for the element itself. If the element has failed, match its wattage, voltage and flange type from the old element or the data plate before you order. For refitting the flange and tightening the bolts, follow the unit manufacturer's instructions.

Mistakes That Cost a Second Visit on a Hot Water Service

• Ordering the rod from the brand name alone. The listing says Dux and Rheem, but it also says the length suits specific models. A rod bought on brand alone can turn out to be the wrong length, and the customer waits another day for hot water. Read the data plate, measure the old rod and ask if the two do not agree.
• Ordering the gasket without checking the flange. The listed gasket is for 4 bolt flange Rheem elements. If the flange on the unit is a different type, the part will not suit, and the job stalls with the tank open. Compare the old gasket before you order.
• Leaving delivery of a 1510mm rod to the last minute. The product page asks buyers to contact SCHNAP for delivery cost, so confirm how the rod will reach you before you book the customer in.
• Switching power back on before the tank is full. An element that is energised in an empty or part-filled tank can be damaged. Follow the unit manufacturer's refill and restart steps, and check the flange once water is back in the tank.

Frequently Asked Questions

Choosing the Parts

What size anode rod do I need for a Rheem hot water system?

The right size depends on the unit, so check the model details on the data plate rather than going by brand alone. The Cabac rod at SCHNAP is 1510mm long and listed for Dux and Rheem hot water systems, with the listing noting it suits specific models. Compare it with the old rod, and ask SCHNAP if the two do not line up.

What gasket fits a Rheem 4 bolt flange element?

The Cabac silicone element gasket is listed for 4 bolt flange Rheem hot water elements, with listed dimensions of 5mm x 100mm x 100mm. Check the outline and bolt pattern against the old gasket before you refit, as the listing covers 4 bolt flange elements only.

Is an element gasket suitable for hard water?

The Cabac gasket is listed as suitable for use in hard-water environments. It is made from silicone rubber, according to the product page.

Is there a warranty on a replacement anode rod?

The Cabac anode rod page lists a 1 year warranty against manufacturing defects. SCHNAP also lists a 30-day returns policy on the page.

Licensing and Electrical Compliance

Do I need a licence to replace an anode rod or hot water element in Australia?

Licensing rules differ between states and by type of work, so check with your state regulator before you take the job. The anode rod page recommends installation by a qualified plumber or technician, and the gasket page recommends a qualified technician.

What MCB rating do I need if I change a hot water element?

If the new element has the same rating as the old one, the load on the circuit stays the same. If the wattage changes, check the breaker and cable against the new load instead of assuming the old breaker still suits. Our guide to choosing the right Lanx MCB rating covers how that decision is made.

Does an electric hot water circuit need RCD protection?

That depends on the installation and the edition of the wiring rules it was built under, so check AS/NZS 3000 and your state regulator rather than assuming. If you are weighing protection options, LANX RCBO vs RCD explains the difference between the two devices.

With the rod length checked and the flange gasket matched, the parts for the job are listed below.

Shop Water Heater Anode Rod Replacement at Schnap

Both parts below sit in our appliance accessories range, with trade pricing and same-day dispatch from Kingsgrove NSW.

Anode Rod

• Anode Rod Magnesium 1510mm Dux Rheem Compatible Cabac: magnesium, 1510mm length, listed for Dux and Rheem hot water systems

Element Gasket

• Element Gasket Silicone Rheem 4 Bolt Flange Cabac: silicone rubber, 5mm x 100mm x 100mm, listed for 4 bolt flange Rheem hot water elements

Need the right water heater anode rod replacement for the job? Browse the range at Schnap.