New boiler ideas

[spacey3]

I am contemplating replacement of our boiler which is currently a Worcester 28cdi Combi.

The boiler itself works and I don't have any issues with its reliability other than I believe it is insufficient for the type of property and that when it was installed by the previous owner no though went into its installation.

The house is long and narrow, has 3 reception rooms and a kitchen with 5 bedrooms and 1 bathroom. It is also End Terrace and is exposed on 1 side in its entirety and the rear and also half way down the other side.

It is over 3 floors, although the upper floor is into the attic space (not a conversion).

All the walls have been insulated, the loft requires further insulation (which I will do once I install a loft hatch and get access to it).

I have looked through this forum and found quite useful information and a great deal of things to think about.

However my issue is where I start, currently the boiler doesn't seem (and this is my opinion) to heat the radiators fully and I believe this is because it is not adequate.

I was thinking of going back to a system boiler with a pressurised water cylinder. I have used an online calculator to work out what KW boiler I would need and it did give me a ridiculous figure of 72 - so I think I was entering something wrong.

I wondered how this is approachable. and what to look for in a replacement, also how much power would be required to make sure that the system heats up the house rather than keeping it warm as it currently does.

I am fond of the Atag A320s at the moment or the Viessmann Vitodens 200 35KW.

I am not sure if these are powerful enough and also if there is anything else that you would recommend.

 

[kevindgas]

so you have 10 rads? each rad needs approx 1.5 KW so thats 15 Kw your boiler is 28kw? think the problem lies elsewhere!! the boiler is perfectly sized in my opinion, maybe radiator sizes are wrong as the installer just used "what he usually uses" and didn't size them for more than 1 outside wall per room.

I would check the boiler is actually running at the right gas rate to do this you can time the meter if its reading in feet then time it (with just the heating running) for 1 full revolution of the dial - record the seconds it took. if its a metric meter take the first reading include the red digits then run the boiler for two minutes - record the second reading
then post on here and someone will tell you if its using the right amount for that boiler to be running correctly.
if you want to email me you can and i will check it ofr you

kev

 

[spacey3]

We have 12 radiators, all doubles apart from 1, I will try what you suggest later this evening and see what results it gives.

The boiler has been 'refurbished', new pump, new expansion vessel, new fan, new heat exchanger, new intake water valve pieces and also the outlet water valve piece, and some new gas piece pilot light.

The radiators are cold in the middle at the bottom, I have sludge removed them (hence why new heat exchanger on three occasions - fortunately covered by a plan).

 

[spacey3]

Meter seems to me metric, 01816.82(7) was the reading after two minuets the reading was 01816.88(7)

 

[dcawkwell]

The system needs balancing properly.

Nothing wrong with the boiler.

It will easily make that place scorching hot.

If the person that looks at the system knows what they are doing.

 

[kevindgas]

agreed!

 

[Agile]

Mr Plumb,

if you want some meat you would go to a butcher?

If you wanted legal advice a solicitor?

So when you need heating advice why not call a heating engineer?

We all think your boiler is plenty powerful enough. We also think you need a good heating engineer!

Tony

 

[Temprise]

Check your primary flow and return pipe size.

If a heating load is greater than 18 KW (60000 btu's) then the flow and return pipework must be increased to 28 mm as a minimum. (its a central heating design specification)

If you have 22mm flow and returns from the boiler to a heat load greater than 18KW then that could be the cause of your problem.

Regards

 

[dcawkwell]

Check your primary flow and return pipe size.

If a heating load is greater than 18 KW (60000 btu's) then the flow and return pipework must be increased to 28 mm as a minimum. (its a central heating design specification)

If you have 22mm flow and returns from the boiler to a heat load greater than 18KW then that could be the cause of your problem.

Regards

Hmm. Strange my 35kW System boiler only has 22mm flow and return pipes.
Maybe I am only getting 18kW out of it

 

[Temprise]

Check your primary flow and return pipe size.

If a heating load is greater than 18 KW (60000 btu's) then the flow and return pipework must be increased to 28 mm as a minimum. (its a central heating design specification)

If you have 22mm flow and returns from the boiler to a heat load greater than 18KW then that could be the cause of your problem.

Regards

Hmm. Strange my 35kW System boiler only has 22mm flow and return pipes.
Maybe I am only getting 18kW out of it

Boiler pipe size should not dictate what system pipe sizes should be.

If there are only 22mm pipes from a boiler then you'd need to step up the size straight away.

Regards