New Boiler dilemma - feedback appreciated

[Jowo]

3 bed, 2 reception room, 2 bathroom, 2 storey house with 11 radiators is looking for a new boiler.

Three suggestions have been made to date by heating engineers

1 - Worcester Bosch Greenstar 25Si Combi (2.2k to install)

From reviews, it says its suitable for small or medium properties which is a bit vague a measurement but I wonder whether it could be a bit under powered. The 28Si model has been described as borderline for a 12 radiator property. Another plumber detests Worcester which he says litter the local scrapyard. Forums seem to be full of people asking how to adjust the pressure.

2 - Megaflow (Quote to follow)

Haven't received the quote yet to know whether its affordable for me but have received assurance that it is a good reliable, non-energy greedy system which means 2 showers could run together at the same time.

3 - Veissman combi boiler with telford 180 litre tank (2.2k)

Championed as an excellent boiler, with a tank that is supposed to be sufficient for 4 people despite being smaller than the Megaflow by around 10-15%. I don't know the proposed model but forums are full of criticisms of earlier boilers which had weak parts. Also, perhaps due to my early 70s upbringing in a council house, I associate cylinders with being poor and lacking energy efficiency...

thanks for any feedback you give.

 

[Jowo]

Also, one engineer has asked me to specify the type of boiler, model, K.W and hot water flow rate I require but most of this is a foreign language to me.

Combis have been suggested by others, models championed include Worcester/Bosch and Viessmann but KW and hot water flow rate is a foreign place for me. Any pointers on this would be appreciated.

 

[bengasman]

WB si is decidedly less good than CDI, and 25 kW is certainly not enough for 2 bathrooms.
Provided that flow and pressure on mains are sufficient, a 37 CDI would do the job, or better a 42. I would advice to thank any engineer that advises a combi of less than 35 kW for his time, and leave him behind.

A heat only boiler could be a lot smaller when you install an unvented cylinder, but the total price will be quite a bit higher. If all is correctly installed, performance will be better than a combi though.

 

[Jowo]

A heat only boiler could be a lot smaller when you install an unvented cylinder, but the total price will be quite a bit higher. If all is correctly installed, performance will be better than a combi though.

By quite a bit higher, are you referring to the Megaflow installation by your mention of an unvented cylinder? Or the combi/telford combination.

And by quite a bit higher, if you are referring to a megaflow, would I be looking at closer to 3k rather than 2.2k, for instance?

think 'London' prices, not Leeds....

 

[bengasman]

The installation of a quality unvented cylinder alone can easily be £1500 - £2000, depending on how much needs doing to bring the water mains up to spec

 

[Jowo]

WB si is decidedly less good than CDI, and 25 kW is certainly not enough for 2 bathrooms.
Provided that flow and pressure on mains are sufficient, a 37 CDI would do the job, or better a 42. I would advice to thank any engineer that advises a combi of less than 35 kW for his time, and leave him behind.

Thanks, I queried this with the plumber who admitted he'd misread my email and thought there was a single bathroom. He's visiting to revise his quote tonight. Might ask him to price Megaflow option.

So I've got the usual dilemma for a 3 bed/2 bath/11 radiator house between

- a powerful combi (downside - bathroom quarrels when 2 hot water points are run)

- megaflow and new condensing boiler (downside - expense, though the promised quote hasn't come through but looks like it can reach 3k)

- new boiler and telford cylinder of 180 litres (downside - just don't understand how this hybrid could work - is this a standard cylinder that is heated via the gas, for example? ).

 

[Agile]

Nowhere do you seem to have said how many people live there!

The hot water requirements depend on that!

Rule of thumb is 50 li plus 50li per person if stored.

Bathrooms need 10 li/min EACH is a combi boiler if yuo want good showers at the same time and will not use any other hot water in the house. Thats not really achievable with a normal combi.

Tony

 

[Jowo]

Thanks.

4 well-groomed ladies, two of which are away from the property around half the time.

Looks like 200 litre plus for a storage system or beefy combi where we simply have to be a bit courteous about not whacking on taps when people are showering.

 

[Agile]

In that case at least 200 li stsored.

If they were Nigerian then at least 300 li !

I would not recommend a single combi. But I would have no problem with a combi for the house and one bathroom and an instant water heater for the other if space is tight.

But all water has to come from the mains and that needs to be measured to see whats possible. Dont get conned.

Tony

 

[Jowo]

If they were Nigerian then at least 300 li !

eek, that's a new one on me.

I've lived with or had Japanese female visitors stay with me, the Japanese being regarded as one of the cleanest nationalities on earth, and in their case, they both bathed like whales and were total bathroom hoggers.

From my youth hostel experiences of sharing dorms with french ladies, I don't think France is going to run out of water anytime soon...

 

[Agile]

Nigerian ladies are often very large and take ages in the shower!