Conflict of Information regarding boiler system.

[kavita83]

Hello All,
I am new to this website - but i am in desperate need for some impartial advice.

My partner and i have have bought a house which we have had extended and refubed - now we are ready for the plumbing side of things - it seems to be causing a lot of confusion. The house is a 4 bedroom detached, downsatirs cloakroom, main bathroom with bath, two ensuites with a shower in each.

We were originally advised a combi boiler would serve the purpose - however, now we have had three plumbers out we have been given three different opinions.

We have been advised a standard combi boiler will not be adequate - is this correct? Will a combi boiler service a house this size should two people need to shower at same time and perhaps a washing machine being on - or toilet being flushed? If so would we need to change the mm of the water pipe coming into the main house?

We have been reccommended a Glow Worm Ultracom 2 35 store - but i believe Glow worms do not have a good aftercare service and in Winter can fail.

We have then been reccommended a pressurised system - but if we do this we would need to increase the mm of the incoming water pipe.

Ideally we do not want a water tank - so if we can have a storage combi that would be great - but totally confused as to what would be the best.

Look forward to some ideas.

Many Thanks

 

[WHPES]

Are your showers standard mixer showers (as opposed to high volume watering can drench showers)? If so with a large enough combi you would be OK. You need to check a) the available flow rate from the mains and b) the hot water requirements of the 2 showers to check if a combi is OK. If you have been told you would need to increase the size of the incoming main then I would assume that the first part has been checked, and in this case I would advise you to do just that. Otherwise you are limited to an old fashioned gravity system (tank in loft).

You can run 2 normal mixer showers from a combi but the combi needs to be powerful enough to do so and the mains flow needs to be good.

Dont like Glowworm personally. U get what u pay for.

Your other alternative is an unvented cylinder (e.g."Megaflow" cylinder) with a system boiler.

Avoid tanks in lofts like you say - very old fashioned and not good if you can avoid them.

 

[kavita83]

Hi,

Thank you for your response - yes they are to standard mixer bar showers - nothing fancy, water pressure was measured at 6 bar which i believe is a good pressure. We were looking at a Worcester Bosch 42CD i - but have been told that two people having a shower and then perhaps a toilet being flushed or washing machine in use would dramatically affect the pressure of the water?

Very confused...

 

[SafeGasInstall]

Worcester Bosch Greenstar 30 CDi with Unvented cylinder with capacity of around 250L will be ideal for you !

Worcester are doing promotion at the moment if you get accredited installer to do it like my self they will give you 6 years guarantee !

Unvented cylinders have 25 years guarantee !

Pay top money on the install and will save you ,days and nights without heating and hot water in the years to come !

 

[SafeGasInstall]

more then one shower is recommended to go for unvented storage cylinder will give you lots of hot water plus recovery time of about 15-20 min on the cylinder !

do it properly will save your money and headache

 

[Plumbstar Tom]

Id say unvented all the way, your asking the combi to do a lot of work here

 

[kavita83]

Thank you - does the water pipe coming from the main road need to be a certain thickness to accomodate this - or is the standard thickness suffice - it has been mentioned we may have to have our driveway dug up to accomodate a thicker pipe in order for the combi boiler to work?

 

[leelister6]

To be honest, if you go for a decent combi (Baxi duotec 40 he for instance) I would always suggest having at LEAST one electric shower (There are some really good 11-12.5 kw ones) in case you ever have problems with the boiler, then you can have a hot shower. There are pros and cons with combi's as there are with pressurised cylinders and conventional systems. Without actually seeing the job we can only give personal recommendations based on experience and preferences.

 

[SafeGasInstall]

it is called MDPE pipe and is blue colour ,could be 25mm or 32 mm !you dont dig it up your drive you get mole commpany to mole it for you your plumber knows about this things

 

[SafeGasInstall]

To be honest, if you go for a decent combi (Baxi duotec 40 he for instance) I would always suggest having at LEAST one electric shower (There are some really good 11-12.5 kw ones) in case you ever have problems with the boiler, then you can have a hot shower. There are pros and cons with combi's as there are with pressurised cylinders and conventional systems. Without actually seeing the job we can only give personal recommendations based on experience and preferences.

this is why there is two immersion on the unvented cylinder

 

[kavita83]

Thank you again - right so im clear - a solution for us would be Worcester Bosch Greenstar 30 CDi with Unvented cylinder. Am i right in saying we would not need to change the pipe work? I think and apologies if i have this wrong - the mains water pipe is 17mm or 18mm currently which is standard? Is this okay? Its a 1930's property which in the past had had no restoration work done to it.

If we go for the Worcester Bosch option are you able to indicate approx costs for boiler cylinder and installation?

Thank you

 

[leelister6]

this is why there is two immersion on the unvented cylinder

Yes. Any you have to balance the cost of a system boiler, unvented cylinder, extra pipework, extra labour etc. against the combi/electric shower option. As I pointed out, you would have to see the property layout etc before you could give proper advice

 

[SafeGasInstall]

Yes. Any you have to balance the cost of a system boiler, unvented cylinder, extra pipework, extra labour etc. against the combi/electric shower option. As I pointed out, you would have to see the property layout etc before you could give proper advice

yes I agree with you , but combi for large homes is not the best option IMHO ,I personally dont like the idea of installing combi boilers in large family homes with more then one showers

 

[kavita83]

the Worcester Bosch is a combi boiler - so you say this is not the best option for a house with more than one shower? Therefore would we need to look at an alternative system?

 

[leelister6]

the Worcester Bosch is a combi boiler - so you say this is not the best option for a house with more than one shower? Therefore would we need to look at an alternative system?

You need to do some research on this. A combi boiler heats the hot water instantaneously and the heating is in a sealed circuit. A system boiler also has a sealed C/H circuit but uses port valves to divert some of this round the coil in your cylinder (vented or unvented) to heat your domestic hot water or alternatively you can heat the water in the cyl. using the aforementioned immersions. There's plenty of info on the net and most boiler manufacturers do system boilers as well as combi's

 

[SafeGasInstall]

The boiler i mention is Worcester Bosch Greenstar 30 CDI and it's system boiler used along with Unvented cylinder with storage capacity of around 250 L will do really good on large family home with two showers and hot water will never run out as there is quick recovery on the system 20min max ! Combination boilers like Leelister6 mention are heating water instantaneously,and they do not need storage cylinder as they give you water on demand only ! dawn side not back up ,and tend to break dawn more often then system and heat only boilers ! But when you have a 5-6 years guarantee on it is not your problem and will not affect you financially !

 

[leelister6]

There you go Kavita 83! You will shortly receive 2 invoices by return of post from Myself and SGI by way of a consultation fee Times is hard!!! LoL

 

[SafeGasInstall]

yep £50 each and a case of beer for me (bud please )

 

[SafeGasInstall]

times are not hard ,people are making it look like ! everything is going the same way round imho

 

[woodsy]

Would never advise a combi for your requirements as the hot water demand is likely to be too great, even the larger ones. As previously stated the unvented system is the best for your requirements but cost and the incoming cold main size will obviously determine if this is possible and the rest of us on here can only speculate without seeing the job.

 

[kavita83]

Thanks Guys - think you have all provided me with great info - thank you very much - now i need to go and download to the other half! We may need our own box of bud lol