Intergas Or Viessman On One Pipe Vented Setup Sludge

[JackK]

I was about to pay for a viessman 100 heat only boiler and then did some further research about sludge and boilers

I have a one pipe system using 2 inch pipework! I have cast iron radiators as well so the system is and will always be dirty even with a magna clean

Will the intergas be more forgiving and reliable to sludge and dirty water then a viessman? Its replacing a thirty year potterton floor standing boiler!!!

Any info greatly appreciated

 

[cross thread]

Separate the system using a plate heat exchanger would be my advice.

 

[JackK]

Separate the system using a plate heat exchanger would be my advice.

Thanks but I cant do that - My question was which boiler would be more tolerant of dirty water so that I can replace the one I have

 

[Terrywookfit]

Why can you not separate the system.

 

[Madrab]

The one that has the least moving parts and the largest waterways. Out of the 2 the Intergas is probably the better choice going by that criteria, is it more tolerant with a dirty system is another question and I certainly wouldn't be happy with any system that's dirty

Who told you that a one pipe system with cast rads will always be dirty, if it's flushed properly, inhibited correctly and contains a filter then there's no need for it to be any more dirty than any other system.

 

[old duffer]

Couple of years ago I nearly made that mistake of buying a viessman and the final straw was the fact that every major supplier I called said they held no stock and did not sell many. I went Japanese instead and used Rinnai...the worlds largest seller by volume..so they have it right.
Why use 20th Century when you can use 21st tech

 

[JackK]

The one that has the least moving parts and the largest waterways. Out of the 2 the Intergas is probably the better choice going by that criteria, is it more tolerant with a dirty system is another question and I certainly wouldn't be happy with any system that's dirty

Who told you that a one pipe system with cast rads will always be dirty, if it's flushed properly, inhibited correctly and contains a filter then there's no need for it to be any more dirty than any other system.

Thank you - No matter how well flushed and filter installed it will always have debris from radiator rust - One other point was whether a one pipe system would have too large flow return differential and therefore trip faults all the time. Do you expect that to happen ?

If yes am I advised to buy a cheap heat only boiler (Baxi main) which has less sensors or is it no different on the cheap ones

 

[Johntheo5]

I don't think a one pipe system would have a very high flow/return dT except all the rads are in series with each other, this is the way I would have thought they might look like but maybe this isnt a true one pipe system.

 

[JackK]

Wow thank you so much! I have massive 2 inch pipework and 17 radiators so i expect the diff to be massive by the time it returns to the boiler

Technical team in Viessman told me this might well be a problem and the boiler will always trip up which is why I posed this question

Do the cheaper boilers measure flow return diff and therefore encouraged to buy in my cirumstances?

 

[Madrab]

No matter how well flushed and filter installed it will always have debris from radiator rust

A one pipe system with cast rads will behave exactly the same as any system. Once the rads are cleaned and flushed properly, the system is filled and inhibited and it stablises, the radiators will stop corroding (rusting), just the same as with any common mild steel radiators.

There will always be a little corrosion to start with due to dissolved O2 etc but that will eventually stop and the system will stabilise and the corrosion stops. Another reason for a mag filter to hopefully catch any ferrous material that may head back to the boiler

I look after a number of systems with cast rads, one specifically with a single 28mm S/S pipe system and there is no issue with corrosion, the system needed a proper clean and flush to start with but a number of years later, it is still absolutely fine.

 

[JackK]

I cannot get the rads off the wall to power flush the rads. I ask do not want to power flush as pressuring the system might cause a leak under buried pipe work.

What are my options

 

[monkeysballs]

If you don't flush boiler warranty will be voided usually. You dont need to power flush though there are other methods then fill-up using vdi2035 and then if it's an air tight system no sludge.

 

[JackK]

If you don't flush boiler warranty will be voided usually. You dont need to power flush though there are other methods then fill-up using vdi2035 and then if it's an air tight system no sludge.

Thanks - All makes sense - Was planning to add chemicals for a few weeks and then drain it really thoroughly and inhibitor - It wont be air tight because there will always be a need to bleed the radiators and its unvented system

 

[Madrab]

Yup, no manufacturer will honour any warranty if the system isn't clean to start with. The rads don't need to come off the walls to allow them to be powerflushed. Even then though a good cleaner for a week or two as you suggest and then several gravity drains and mains flushes may be enough if there are suitable drain points, really depends on how manky the system is at the moment. Either that or each rad can be drained/flushed/drained whilst on the wall quite easily, are they big so floor standing too?

An engineer, well versed in single pipe systems, should be able to sort it out without too much trouble. Ensure they know single pipe systems as they are quite unique and easy to unbalance. Is the system currently a sealed system?

 

[JackK]

Yup, no manufacturer will honour any warranty if the system isn't clean to start with. The rads don't need to come off the walls to allow them to be powerflushed. Even then though a good cleaner for a week or two as you suggest and then several gravity drains and mains flushes may be enough if there are suitable drain points, really depends on how manky the system is at the moment. Either that or each rad can be drained/flushed/drained whilst on the wall quite easily, are they big so floor standing too?

An engineer, well versed in single pipe systems, should be able to sort it out without too much trouble. Ensure they know single pipe systems as they are quite unique and easy to unbalance. Is the system currently a sealed system?

The system has a F*&E tank in the loft - Its vented - So not sealed if I am correct. Given all of this what heat only boiler can you suggest?