Small Conventional Boiler

[Dan0803]

Hello

I need to have a new boiler fitted - to replace existing small boiler. Existing boiler all working fine but it is very old and I just want peace of mind. Boiler is to support 4 radiators in a small 1 bedroom starter home and it will need to provide hot water for storage in the existing hot water cylinder.

I'd be grateful for experienced opinions and I am looking at the longevity and ease of repairs for future breakdowns.

Current boiler is in a kitchen standard kitchen 600mm kitchen cupboard.

 

[Agile]

It would be good for you to quote the actual age and the boiler make and model.

If it is working fine then most would say leave it.

Many older boilers are far more reliable than new ones!

One Client has a Potty boiler which is so old that you light the pilot with a long match! No fancy ignitors on that one!

 

[Dan0803]

The boiler I have is a Baxi Solo 2 30pf. Its covered under a maintenance agreement but they keep telling me I should upgrade as they say the parts will probably end up obsolete. I think the boiler is 20 years old.

 

[muggles]

The most suitable boiler on the market for your system would be the Viessmann 200-W 11kW. It's the only one out there which can modulate low enough to sensibly & efficiently run a system that small.

 

[ianmcd]

The boiler I have is a Baxi Solo 2 30pf. Its covered under a maintenance agreement but they keep telling me I should upgrade as they say the parts will probably end up obsolete. I think the boiler is 20 years old.

That is simply the BG Hymn

 

[vulcancontinental]

The most suitable boiler on the market for your system would be the Viessmann 200-W 11kW. It's the only one out there which can modulate low enough to sensibly & efficiently run a system that small.

Could you put some figures on that muggles to quantify sensible and efficient? A starter home might have a 5kW loss in the extreme weather and minimum 3kw load DHW. Sure it would work but suitable can have several definitions. This is a post for discussion not a confrontation, I know you're a thoughtful installer.

 

[Dan0803]

That is simply the BG Hymn

??

 

[bernardgreen]

In the specification by PlumbNation of the Viessmann Vitodens 200-W 11kW Natural Gas it says

• Modulation range 1:17

11kW down to 0.65kW

What are the efficiency ratings at 11kW and at 0.65kW ?

 

[ianmcd]

??

It is what they say to get a boiler sale, they constantly lie to you, it is company policy to do so, they call it best advice , we call it ripping people off

 

[sxturbo]

Could you put some figures on that muggles to quantify sensible and efficient? A starter home might have a 5kW loss in the extreme weather and minimum 3kw load DHW. Sure it would work but suitable can have several definitions. This is a post for discussion not a confrontation, I know you're a thoughtful installer.

the boiler currently installed is a 9kw boiler, i presume installers usually specify whats already installed unless the customer is making changes to the system, like an extension for example, or adding additional radiators.

 

[muggles]

Could you put some figures on that muggles to quantify sensible and efficient? A starter home might have a 5kW loss in the extreme weather and minimum 3kw load DHW. Sure it would work but suitable can have several definitions. This is a post for discussion not a confrontation, I know you're a thoughtful installer.

A system with 4 radiators is unlikely to need more than about 5-6kW maximum, assuming they aren't all enormous. That's lower than the minimum modulation of a lot of boilers. The 200-W will modulate to 1.9kW which at least gives it a chance of operating without too much cycling.

 

[vulcancontinental]

A system with 4 radiators is unlikely to need more than about 5-6kW maximum, assuming they aren't all enormous. That's lower than the minimum modulation of a lot of boilers. The 200-W will modulate to 1.9kW which at least gives it a chance of operating without too much cycling.

Yes that's what I reckon but it's the costing as well. A £1600 boiler for a 4 rad job.

It's not the max but the min output needed I would think of as probably 1kW would do it for much of the heating season.

An £800 20kW boiler at 1:8 mod would drop to 2.5 and if 1:5 4kW.

They reckon if a burn of 3 minutes or longer is achieved the hit to efficiency is 1.5%. The annual bill for four rads is possibly £600 so a £9 saving each year.

With an adjustable anti cycle that burn time could be achieved and £800 saved.

Plus there will not be a £580 PCB to replace if it fails.

 

[Razor900]

Now how about you take that £800 saving and use it to upgrade the insulation in the property?

Then you could potentially set the anticycle time to say 15 mins or so.

All gas boilers burn gas the clue is in the name but I've never seen a survey showing the overall costs of identical situations with an efficient band a boiler against a super efficient band a boiler.

The government's own chart for boiler plus makes it clear there is almost no cost saving to be made. Advanced controls have convenience advantages rather than financial

Stopping the heat leaving the property is probably more important than which boiler you fit.

Of course that's not to say the boiler isn't an important part of the package but I'd say the quality of installer matters more

 

[Dan0803]

Yes that's what I reckon but it's the costing as well. A £1600 boiler for a 4 rad job.

It's not the max but the min output needed I would think of as probably 1kW would do it for much of the heating season.

An £800 20kW boiler at 1:8 mod would drop to 2.5 and if 1:5 4kW.

They reckon if a burn of 3 minutes or longer is achieved the hit to efficiency is 1.5%. The annual bill for four rads is possibly £600 so a £9 saving each year.

With an adjustable anti cycle that burn time could be achieved and £800 saved.

Plus there will not be a £580 PCB to replace if it fails.

I am totally confused. Clearly not my lingo.

I can't afford a £1600 boiler plus of course the fitting on top. What is the problem if I put in a cheaper larger kw boiler?

 

[ianmcd]

What is the problem if I put in a cheaper larger kw boiler?

It will constantly cycle