advice on which boiler

[stewpot2010]

Hi Guys
Am a newbee so please be gentle, I am looking for advice on which combi boiler to buy and any help would be gratefully received. I have a fairly large stone built semi with 3 large bedrooms( 1 onsuite on second floor ) family bathroom with shower and bath, large living room, alrge kitchen, utility room and cellar. 12 rads at the moment services by (just) an ideal c24. I am going to change the boiler and am wondering about the Vailiant 937, alpha cd50 as these seem to be able to give the dhw that we desire. At the moment if someone is in the shower and a tap is turned on it goes cold, can anybody advise ta.

 

[solman]

if you have high dhw usage stored hot water maybe the right choice combi boilers are not always suitable with larger properies i have a 5 bed system boiler 30kw vented cylinder and aqualisa power shower and everything performs great

 

[solman]

i forgot worcester and vaillant around 28/30 kw will be fine

 

[stewpot2010]

thanks for that solman, got a guy coming monday and I'll put this to him. cheers

 

[mickyg]

whats your cold water flow rate like from kitchen/garden tap?

 

[stewpot2010]

i measured it today by filling a jug (hope this was right) ober and over and worked out at about 15 ltrs aminute from the cold tap but only about 7/8 from the hot tap

 

[mickyg]

no point having a boiler that provides anything more than 12-14l/min. You will still get a reduction in pressure when you open another tap.

 

[stewpot2010]

Has anybody got experience with the Alpha cd50 as it boasts a very large storage capacity which I thought might help my problems?

 

[stewpot2010]

ta mickeyg do you think it would help to have the storage facility in the combi or should i go for a seperate tank?

 

[onlyfitidealboilers]

id go unvented cylinder an system blr

 

[stewpot2010]

I know that I'm probably being really dumb but can I have a system boiler and unvented boiler in the cellar, this is where the existing combi boiler is and there is loads of space there?

 

[mysteryman]

Yes, you can put them in a [dry] cellar. This is the usual way in Germany.

 

[Rob]

id go unvented cylinder an system blr

Really? With a 15lpm flow rate Seems a bit of a waste and wont solve any problems

OP, Your flow rate is what it is. Apart from checking the obvious things like main stopcock etc

A big boiler with storage or whatever wont improve it.

 

[onlyfitidealboilers]

id go unvented cylinder an system blr

Really? With a 15lpm flow rate Seems a bit of a waste and wont solve any problems

OP, Your flow rate is what it is. Apart from checking the obvious things like main stopcock etc

A big boiler with storage or whatever wont improve it.

didn't read that post

 

[mehran]

At 15l/m then it is firmly in combi land. forget the cd50 you best go for 30 to 36kw combi.

I would recommend an intergas HRE 36kw combi with 15l/m flow. if you are looking for more flow then you could pump from cold water tank to boost the flow then you could look at higher htw water flow systems like ones with unvented tanks