which worcester greenstar combi?

[Fred]

Guys,

got three quotes for combi boiler and all plumbers agree that what I need is a 30kw boiler for 4-bed/one bath/shower house. Looking at the specs for the WB Greenstar 30 I see that its flow rate is 12l/35 degrees. The mains flow of the house is between 15 and 20l/min. I have no plans to install a second shower or bathroom, but I am worried whether I should go for the 35 in order to allow a hot tap to be opened elsewhere in the house. It comes with hot water flow rate of about 14l and costs round about 300 pounds more. Needless to say that

300 pounds is a lot of money if it never gets used after all. Anybody with experience of a 30kw boiler and somebody doing the dishes downstairs?

Best,

Fred

[Andy Hall]

That's pretty marginal....

One of my neighbours has a 30kW boiler and the supply is similarly limited. This was a replacement for a roof tank system, and they are disappointed with hot water performance. They were sold the line that mains pressure hot water would be good etc. but have found the flow and pressure to be poor for the shower compared with their old system with a shower pump, especially in the winter. They have to avoid using taps downstairs when the shower is in use, or it slows to a trickle.

Bear in mind that in the winter, the cold mains temperature is 5-8 degrees, so in practical terms most of the water for a shower at 40 degrees will have to go through the boiler. Given that the boiler rating is fairly close to what the supply can do, it's not going to make a huge difference, but I would probably err to the higher performance model to be able to get a bit more out of it.

[John Rumm]

I installed a 35kW unit at the start of the year, and have slightly better mains flow that you (but not by much).

It is "ok" but not startling. In the summer, it is about as good as the stored water system that it replaced (which was nothing special as far as these things go). In the winter bath filling times are a bit protracted. Showers are good all year round.

Personally I am glad I went for 35kW rather than 30 since it can cope with a shower and something else if used carefully.

I went for an Ideal Isar - the price difference between 30 and 35kW was far less than 300 mind you (you should be able to get the 35 for 800-900).