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It has been suggested to me that a thorough power flush of a dirty system with cleaner can't be done in one day. Maybe more like several days to a week?
 
It has been suggested to me that a thorough power flush of a dirty system with cleaner can't be done in one day. Maybe more like several days to a week?

naa depends how many rads and how bad
 
It's a biomass system with a 650 litre buffer tank and 100 metres of underground pipe to two properties. The circuit in question is separate to any radiator circuits, that is separated by heat exchangers.
 
It's a biomass system with a 650 litre buffer tank and 100 metres of underground pipe to two properties. The circuit in question is separate to any radiator circuits, that is separated by heat exchangers.
So its a normal domestic set up not...why did you not state this
huh...I think I would rather watch the tennis centralheatking
 
The suggestion is that one day was not long enough for the power flush cleaner to do its work. Plus the time it takes to thoroughly flush out the residues.
 
So its a normal domestic set up not...why did you not state this
huh...I think I would rather watch the tennis centralheatking
Throughout my threads I have never said that it is a normal domestic system. It is a biomass 70kW ETA boiler system burning woodchips. Please read.
 
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Depends on the system, its always good to run the cleaner with heat for as long as the manufacturer recommends. Sometimes up to two weeks and I think a minimum of 2 hours if I remember right.

What you've got to remember Trevor rix is the engineer who's quoted for your flush is trying to anticipate all outcomes, him flushing the system leaves him wide open to any future problems... so its good he's giving you honest information and a realistic price. It means hes going to do a good job!

But of course, when in doubt always get 3 quotes
 
The cleaner was run with heat for around 2-3 hours.

The current problem is that I can't obtain the information as to how long the manufacturer recommends the cleaner should be run for (see above).

The power flush cleaning and refilling of the system with inhibitor was done by the original supplier/installer of the whole system, free of charge, because of the numerous problems that I have discussed in my four threads in here. No one else has done any work on the system.

Therefore no prices involved and no quotes required.
 
whats the problems eg sludge or just colour of the water?
 
whats the problems eg sludge or just colour of the water?
The problem prior to the power flush cleaning was the colour of the water - dirty brown, brown sediment in the bottom of the sample jar when left to settle, and a pH of 4.73. When the two Fernox TF1 filters were flushed the contents were dark black.

The problem now is that the pH is 6.0 compared to the incoming mains water pH of 6.7. I will take another sample from the drain near the bottom of the buffer tank when the system is cool and the pump has been switched off for a couple of days.
 
Trevor,

A couple of points:

Unless the Manufacturers Instructions (MI’s) from ETI have changed, the ETI boilers I have installed have all required the primary circuits to be on softened (ion exchange) water with a PH above 7 preferably higher. Your MI’s will define how ETI require the primary water to be treated (or otherwise).

I think that a call to ETI technical explaining the issues that you are experiencing would give you an insight into a range of possible solutions. Whenever I have had an issue with their equipment, the advice has always been excellent.

In general terms, to achieve ETI’s MI the complete psystem is pre-commissioned, immediately after installation. If there are extensive runs of pipework from the boiler house to remote heat exchangers, this is normally with a citric acid clean, neutralised and then, if stainless steel, passivated.

If you are getting a low PH, it is likely that that is just a snap shot in time - the PH will rise and fall as the oxidation process, from green rust to hydrated iron oxide to red rust and then magnetite takes place. This is a constantly ongoing fluctuating process as the steel corrodes.

The type of inhibitors you are referring to are to stabilise systems that are fundamentally clean. An inhibitor added to a system that is actively corroding is unlikely to stop that process.

The chemistry in every system is different - but for domestic systems a “one solution fits all” system is generally cost effective and a satisfactory long term solution. For larger / small commercial systems that philosophy also generally holds - provided that the system was properly pre-commissioned after installation.

However, once the chemistry of oxidation has become well established in a larger system - it normally needs the primary water to be analysed and a bespoke flushing regime developed and executed. That may involve a further acid clean to remove the various iron oxides and salts. Thereafter, once the system is stable it can to reflushed set up in accordance with the MI’s

It is not as simple as just dosing an acidic water with alkali to increase the PH. The PH is an indicator of what is going on in the system.

Be aware ( if it has not already been mentioned), the use of inhibitors in boiler primary systems is, in my experience, very much a UK thing. Elsewhere, it is often common to use untreated water produced by Reverse Osmosis as the stable solution in a clean system. Hence the ETI MI referring to the use of softened water ( albeit artificially softened water is not without it’s problems in complicating boiler water chemistry)
 
Apologies, that’s because I was typing whilst watching tennis highlights! My reference was to ETA biomass boilers - their MI’s refer to using only softened water in the primary circuit, dosed (where required) with up to 30% glycol.

If you look in the Warranty section of the ETA manufacturer’s instructions - unless it has changed recently - it clearly sets out the water quality criteria to maintain the warranty. I have only fitted three Hack 30/70’s - but I am sure that the same criteria applied as per the smaller boilers in their range of which we have installed over 40.
 
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Brambles, your post has prompted me to look at the ETA Hack 70 user manual. I am not sure how relevant it is to my topic? Page attached.

ETA HACK_User_Manual_page 37.jpg
 
The original commissioning was overseen by an expert from the UK sole importers of ETA boilers, so I assumed that it had all been done properly.

As far as I am aware only standard mains water was used which is relatively hard in my area. Plus Trade-Chem inhibitor.
 
Trevor,

I only have a ETA Hack 20/90 manual to hand, your manual my be different. If you look in section 3 ( Warranty) it sets out all the criteria that are required to maintain the as sold warranty for the wood chip boiler. That includes, but is not limited to, using only softened water in the primary circuit and filling with water of a PH 8 / 9.

With respect to Trade Chem, I have never seen it as a recommended inhibitor by any boiler manufacturer. That is not to say that there is anything wrong with it.

A call to ETA will quickly resolve all of the issues raised in your thread
 
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Quote below from the warranty section of the user manual. But, it was mentioned in this thread that in the UK softened water is not commonly used?

"Water is the intended heat-transfer medium. For
special anti-frost requirements, up to 30% glycol
may be added. Softened water is required for
the initial fi ll-up of the heating system and for
refi lling after repairs. For the initial fi ll-up of
boilers up to 90 kW, the value of 20,000 lt°dH
for the system volume in litres multiplied by the
hardness (in degrees of German hardness) may not
be exceeded. For boilers over 90 kW, the limit is
30,000 lt°dH.

The pH value should be set between 8 and 9.
Addition of hard water should be minimised to
limit limescale build-up in the boiler. Set enough
shut-off valves to avoid bleeding large amounts of
water during repairs. Any leaks in the system must
be repaired at once."
 
The issue with artificially softened water from a traditional ion exchange water softener is the magnesium and calcium ions are replaced by chloride ions. That is not ideal in a boiler, because it makes the water a better electrolyte ( one of the three components that helps corrosion).

Water softened by reverse osmosis does not have that issue.

Having said that, I think that is preferable to having acidic water circulating long term in the system.

I only raised this point that from my own experience to maintain the manufacturers warranty - we pre-commission ETA boilers (and occasionally need to acid clean) then use softened water.

Generally, in heating, if you deviate from the MI’s in ether installation or operation, always get a concession in writing from the manufacturer.

Apologies if this is now getting off topic
 
Brambles, your input is most welcome. Helps me understand the issues and decide what to do next. I think I will phone Innasol as you suggest.
 
It has been suggested to me that a thorough power flush of a dirty system with cleaner can't be done in one day. Maybe more like several days to a week?
Define power flushing?
That is the common problem, how many times do you need to completely drain & refill the system for example to dilute / remove the cleaner?
It is all about the amount of time & effort an engineer wants to put in against how much a customer wants to pay.
 
In my case it's not about the cost because the I am not paying. It's all about having the job done properly resulting in this expensive system being in a safe condition not subject to corrosion.
 

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