Power Flushing, warranty & cleanliness of system

[Frankenstein]

I've now had several quotes from company reps for my replacement boiler. All of the installers say that my system needs to be flushed prior to installation of the new boiler (chemical or power I'm not debating on the type of flush).

I've been told that if my boiler has a problem within the warranty period then then the manufacturer will probably test the system to see if its dirty - fair enough.

So I asked a company rep that if a manufacturer can test my system to determine if its dirty, then how does the installer know when the flush has done its job - is there a test for clean as there is a test for dirty, or is there a threshold of some sort for the level of dirtiness (assuming that perfect cleanliness is not achievable)?

The reply was: 'it will be flushed until its clean'.

So here's my question (and i will try to be as specific as I can):

If there's a way to test if the system is dirty, is there a way to test it if its clean following the flush?

The rep seemed quite knowledgeable but but he didn't understand what I meant when I asked about the modulation ratio of a boiler, and I couldn't press him much about the flushing. As I'm still new to understanding boilers, I find it difficult to determine how good some of these reps are or whether I'm asking them the right questions.

 

[Scott_D]

Send a sample away for anaylsis

 

[Ray Stafford]

There isn't a specific threshold, but the general indicators are:

• Cold spots on radiators (either detectable to the touch, or easily seen on a thermal imaging camera) indicate a build up of various undesirable deposits. A radiator giving even heat output across the entire surface is generally clean
• Colour and clarity of water
• Whether a magnetic filter is still gathering debris after multiple passes

Then there are chemical tests for the presence of corrosion inhibitors. Unfortunately, there are several different chemical approaches to corrosion inhibition, and there is no universal test. However, the absence of inhibitor does not make the system water dirty of itself - it is simply an indicator that the system may well deteriorate in the future.

 

[Frankenstein]

Send a sample away for anaylsis

Do I not get an analysis report before and after my system has been flushed? I would have thought that some sort of certificate to show the following would be quite useful;

a) Date/proof of flushing
b) Analysis of sample before flushing
c) Analysis of sample after flushing

 

[Frankenstein]

There isn't a specific threshold, but the general indicators are:

• Cold spots on radiators (either detectable to the touch, or easily seen on a thermal imaging camera) indicate a build up of various undesirable deposits. A radiator giving even heat output across the entire surface is generally clean
• Colour and clarity of water
• Whether a magnetic filter is still gathering debris after multiple passes

Then there are chemical tests for the presence of corrosion inhibitors. Unfortunately, there are several different chemical approaches to corrosion inhibition, and there is no universal test. However, the absence of inhibitor does not make the system water dirty of itself - it is simply an indicator that the system may well deteriorate in the future.

Looks like some companies could have a lot of wriggle room to void a warranty! Maybe Worcester Bosch is the way to go - they seem to have good reputation for upholding their warranties.

Thank you!

 

[Scott_D]

Do I not get an analysis report before and after my system has been flushed? I would have thought that some sort of certificate to show the following would be quite useful;

a) Date/proof of flushing
b) Analysis of sample before flushing
c) Analysis of sample after flushing

You can anything you are prepared to pay for.

 

[Masood]

If there's a way to test if the system is dirty, is there a way to test it if its clean following the flush?

Yes, it's the same set of tests. TDS, turbidity, pH. If you want to get really technical, you can send samples off to be analysed.

BS 7593:2006 does not give tolerances/thresholds but a good rule of thumb is that if the system water is within 10% of mains water in the area then the system is clean. The European standards (VDI2035, SWKI, ÖNORM) are more specific.

Contrary to what you've read Worcester are notorious for water quality sampling and using that as a reason to void warranties. Bizarrely, they will often still carry out a free repair as a goodwill gesture.

As for the reply the "it'll be flushed until clean" - that's actually as good as it needs to be. An experienced person can tell visually when the water is close to mains quality. He/she will know how to flush thoroughly so will be certain that no deposits have been left in areas of sluggish circulation (there's a technique for dislodging them that the right equipment, used correctly, will shift) and then all that remains is to do the three tests I mentioned before.

I really think you're going about things the wrong way - you risk alienating good people by interrogating them. It sets a tone of mistrust and suspicion. Find companies with excellent reputations locally, and trust them - they won't have gained good reputations for nothing!

 

[rocketmanbkk]

Do I not get an analysis report before and after my system has been flushed? I would have thought that some sort of certificate to show the following would be quite useful;

a) Date/proof of flushing
b) Analysis of sample before flushing
c) Analysis of sample after flushing

Yeah right

Analysis report?

 

[Masood]

Yeah right

Analysis report?

There are firms that do analysis but they're not cheap, and it would make the job drag out. One visit to take a sample, then a week to 10 days waiting for results, then flush & install, then wait another week to 10 days for the results.

If I were working to that spec, with the aim of making it absolutely impossible for manufacturer to blame water quality, I would want the test results back before commissioning the boiler! That's a long time with no heat & hot water...

 

[rocketmanbkk]

There are firms that do analysis but they're not cheap, and it would make the job drag out. One visit to take a sample, then a week to 10 days waiting for results, then flush & install, then wait another week to 10 days for the results.

If I were working to that spec, with the aim of making it absolutely impossible for manufacturer to blame water quality, I would want the test results back before commissioning the boiler! That's a long time with no heat & hot water...

Agreed & you'd never win a job!!