Ideal Mexico 2 Replacement With Commercial Size Pipework

[ChloeRadshaw1]

I have a residential house which has commercial pipework and a system in place - It is a gravity fed system. I have had quite a few heating engineers come to the house and they all have suggested to switch to a combi boiler even though the house has five bedrooms and two bathrooms and 15 cast iron radiators - The cost seems to be between 8 -10K to do that

The current boiler is an ideal mexico 2 and works but could do with changing which I want to do as this house is my forever home

I have two questions for the wise people on this forum

1) Would you recommend that this regular boiler is changed to a combi boiler (One engineer even wanted to run plastic pipework and bypass the steel 50mm pipework which left me very unhappy) or should I stick to a heat only regular boiler?

2) The flue running outside the house goes all the way to the top of the house - Can this be reused as this was expensive to install many years ago

 

[vulcancontinental]

It's a strip out and start again. You'll need a boiler and a hot water cylinder either unvented or vented dependent on cold main pressure and loft space. Shop around for an experienced engineer. How many is quite a few heating engineers? Find more. Don't use the flue again.

 

[gas112]

as per Vulcan
and no boiler available these days use that sort of flue also your present boiler is not within the house if you want to keep it there , there is only a few manufacturers that allow it so needs relocating

 

[bernardgreen]

I have had quite a few heating engineers come to the house and they all have suggested to switch to a combi boiler

which suggests they are profit seeking installers, they are not heating engineers.

 

[ChloeRadshaw1]

The house i live in is a detached house but has a commercial size pipework and the boiler is in an outhouse with the flue running up vertically along the house

So far I have had heatable suggest that I remove the vented regular boiler and install a vitodens 100 boiler as a combi option. I have asked for a 222 Viessmann so that it can remain in the same location but that was not an option

I am concerned about

1) the pipe work is buried in the walls and is steel pipe work. That is the case for central heating and hot water and the combi boiler will pressurise the pipes to a higher bar pressure and cause weeping joints and leaks which will remain undetected. Can you share your comments please

2) is a vitodens 100 combi suitable for a large detached four bed two shower house and will it be as hot water as a regular boiler which has a vented cylinder

3) the pie work is commercial sized steel for central heating and some hot water. Is this a benefit and should be retained or is 22mm copper piping better to redo in. The current system was expensive to install at the time and I do not wish to spend money and end up with a less attractive outcome

4) I would prefer the boiler remains outside the house and in outhouse so that there are no gas emissions in the house. I do not want the boiler in the loft unless I have no choice

My current thinking was to replace the boiler with another freestanding heat only boiler and reuse the expensive commcerial style flue. Gas advisers (who charge for the quote) advise me to put a combi in the log and suggest using plastic piping to get rid of the expensive steel pipes

 

[oldbuffer]

1. Personally don't think a combi is suitable for a house that size with two bathrooms.
2. I'd go for a heat only boiler with a pressurised heating system. Far less prone to corrosion / sludge issues. Also means that things like the pump are separate, and you are not bound to the boiler manufacturer's spares prices.
3. If you have the pressure and flow rate, you could consider an unvented hot water system.
4. If it were me I'd get rid of the steel pipework, more likely to cause corrosion. However, it would be a costly part of the job, so you could consider keeping it but make sure the system inhibitor is changed every 2 to 4 years.
5. If changing the pipework, then given the use of cast iron radiators, I'd go for 28 mm to each zone (upstairs, downstairs) and 22mm thereafter 22 mm spine and short 15 mm lengths to each radiator.
6. You expect this to be your forever house. This suggests you will have to change the boiler again at least once in your occupancy. You may need to consider some form of heat pump in future, which to me suggests:
6.1 Don't get rid of airing cupboard / hot water cylinder.
6.2 Keep the pipe sizes on the high side to give a better chance of coping with the lower flow temperatures of a heat pump system.
7. I would suggest your first two tasks are to establish:
7.1 the static and dynamic pressure of the incoming cold mains supply.
7.2 The heat loss requirements for the proiperty.

 

[JohnD]

I'm sure Chloe will say thank you when she gets round to it.