Central Heating Corrosion Test

[John506]

Hi

I have looked over the internet but can't quite find what I am looking for, I need to know a simple corrosion test often used for central heating systems, any help will be appreciated, thanks...

~John

 

[ollski]

Do you mean an inhibitor test kit?. Corrosion gives itself away by colour smell and blockages.

 

[John506]

I'm doing a course and I have questions but no material to find the answer in, the question was "Describe the simple corrosion test often used on central heating systems."

I think that the inhibitor test kit fits correctly as the answer, also I can research it to explain how it works, thanks for your help

 

[kevplumb]

bleed a rad and see if the gas is flammable

electrolitic corrosion (and the spell checker did that )

 

[JohnD]

Or maybe "open a bleed valve, see if gas comes out, see if it will ignite (hydrogen)

(bah, beaten by Kevplumb

 

[nickso]

you can take a water sample and have it analysed for content

 

[John506]

Do you guys know the most common way a plumber would do it, or do they all equally use different methods?

 

[ollski]

I think they are probably referring to the nail in a jar of water method.

 

[John506]

can you explain the nail in the jar method please?

 

[JohnD]

drain off a bit of water into a clean jamjar, put in a bright steel nail, shake, see if it goes rusty. Or use wire wool which is faster.


I do that too

 

[oilman]

Put water in jar. Put nail in water. Wait a week to see rust. (Don't use plated nails).

 

[John506]

Are iron nails ok to use? (aswell as steel)

 

[oilman]

I doubt you will find iron nails except in a museum.

 

[candres]

Laughed my @rse off as I read the last two posts.

 

[Onetap]

I'm doing a course and I have questions but no material to find the answer in, the question was "Describe the simple corrosion test often used on central heating systems."

The nail in a jam jar test is often used, invariably by idiots.

The nail would rust if there were dissolved oxygen in the water. There is bog all oxygen dissolved in a jam jar of central heating water, but leaving the jar open to the atmosphere will allow oxygen to be dissolved. Removing a sample from the system will allow it to dissolve oxygen and distort the test results.

Corroison is the result of dissolved oxygen, either from pumping over, oxygen permeating through non-barrier plastic pipe or from electrolysis due to galvanic corrosion and acidic system water.

The only sensible test is a chemical test kit to measure the concentration of the oxygen scavenger chemical in the sample.

For a proper corrrosion test of the nail in water type, go Google for the phrase "corrosion coupon rack".

If your instructors recommend the nail in jam jar test, you need to consider getting proper training elsewhere.