Sacrificial Anodes in your HWS

pmrid (Peter) · #1 04-04-2015, 11:02 AM

A heads-up for anyone with a Hot Water System that has a sacrificial anode - check them regularly.

I just did a "better-late-than-never "check on the HWS in my 7y.o Jayco poptop. I've owned it for 2 years but never thought to check it. Wow! It started life as a 10 inch x 1" dia rod of magnesium. There was NOTHING left of it and the tank was full of while mineral salt deposits and looked like hell.

As a side issue, I have also noticed that my domestic HWS has a similar anode. Before I start trying to pull that one out I thought I might check with anyone else who has any knowledge of these things.

Peter

raymo · #2 04-04-2015, 04:40 PM

Almost all domestic hot water units have a sacrificial anode which is
checked when the periodic service is carried out,[ if it is carried out, many
people don't bother, not knowing about the importance of the anode].
It is important to get the right colour anode for the area where the
heater is located, as different residential water supplies can require
different anodes. The most common one is black.
raymo

RB (Andrew) · #3 04-04-2015, 06:22 PM

Yes I check it regularly and change as needed.
I get the one specific for my area.
It is very important to do this if you want to prolong your HWS's lifespan.

Easy to check, just stop the water supply, release some pressure and unscrew from the top of system to pull the SA rod out and check it.

RB

Baddad (Marty) · #4 05-04-2015, 09:33 AM

It is advisable to be done every 5 years. Some earlier tanks do not have an anode. Saxon tanks because they are copper. Also very early tanks which were made and imported from Germany. I have seen these still operating after 40 years. Saxon tanks seem to blow after 25 years.

The ones with anodes are made of steel and enamel coated. However the water does contact the inner tank metal through tiny cracks that develope over time.

Glenhuon (Bill) · #5 05-04-2015, 01:09 PM

As an ex Water Supply fitter I would advise you check the Anode annually. Water quality fluctuates over time due to changes in the chemicals in it, a bit too much Chlorine or a change of source for instance and the Anode takes a knock. If is down to 10/15%, change it. They are not expensive when compared to a new tank and can more than double the life of your Water Heater. At the risk of upsetting some in the trade

. you don't need a plumber, unscrewing an Anode and replacing it (with a new sealing washer) is not rocket science. Like the man said, turn off the water, turn off the power, drop the pressure, and unscrew. Forgot to add, while you are at it, pull the lever on the pressure release valve before you turn the water off and give it a quick squirt to clean it out, if it won't close properly and drips. Have it changed.

AstralTraveller (David) · #6 05-04-2015, 02:57 PM

Thanks for the heads-up. Does this apply to gas heaters or only electric?

raymo · #7 05-04-2015, 03:09 PM

Gas and electric.
raymo

Hagar (Doug) · #8 05-04-2015, 09:57 PM

Quote:

Originally Posted by pmrid

A heads-up for anyone with a Hot Water System that has a sacrificial anode - check them regularly.

I just did a "better-late-than-never "check on the HWS in my 7y.o Jayco poptop. I've owned it for 2 years but never thought to check it. Wow! It started life as a 10 inch x 1" dia rod of magnesium. There was NOTHING left of it and the tank was full of while mineral salt deposits and looked like hell.

As a side issue, I have also noticed that my domestic HWS has a similar anode. Before I start trying to pull that one out I thought I might check with anyone else who has any knowledge of these things.

Peter

Hi Peter apart from all the issues that come with a non existent anode, something that you might like to keep in mind is that for some years caravan manufacturers have been installing a tempering valve into the hot water line which mixes some cold with the hot water to reduce the temperature to a level which won't burn you or children. The white alloy salts that remain as a result of the anode doing it's job can and do often block the mesh screens on the hot water inlet to the tempering valve resulting in just luke warm hot water. If it does happen you need to remove and clean the mess filter and flush all the white gunk out of the hot water system.
I have had anodes disappear in just one year, particularly when travelling through SA.

pmrid (Peter) · #9 06-04-2015, 05:30 AM

Thanks Hagar. I'll have a look for that tempering valve.
Peter

ZeroID (Brent) · #10 06-04-2015, 01:12 PM

HWS and anodes ?
Seems to not be a problem in NZ. No anodes over here, no system checks and tanks last 25 - 40 years. I've never replaced a tank, just the elements on rare occasions.

Who knew ?

pmrid (Peter) · #11 07-04-2015, 07:40 AM

Quote:

Originally Posted by ZeroID

HWS and anodes ?
Seems to not be a problem in NZ. No anodes over here, no system checks and tanks last 25 - 40 years. I've never replaced a tank, just the elements on rare occasions.

Who knew ?

That would undoubtedly be because NZ water, like everything else across the ditch - and as everyone well knows - contains absolutely no impurities.

Peter