Recommended a combi but not sure...

[foxlj]

Our Conventional boiler need replacing and I have had 2 heating engineers come round and they both recommend it being replaced with a Combi. However a quick google has made me nervous that it isn't suitable for us so I'm after some advice please.

We have 4 bedrooms and 2 bathrooms, both will electric showers. 2 adults and 2 young children but who will grow into 2 (maybe more) teenagers in this house. The advice that I have read suggests that conventional systems are better for large households/families but both heating engineers suggest that suitable combis nowadays can also cope fine. The 2 that they suggest are a Baxi Platinum 33HE or a Worcester Bosch Greenstar 42CDi. I understand we have good water pressure.

One electric shower is broken but if we go down the combi route I will get a 'normal' shower plumbed in instead. At the moment, the only hot water we use if for the kids bath every other day and a bit of washing up so they make the vaild point that it doesn't seem worth heating a whole tank for that little hot water use.

My main concern is that if we get a combi, will be be able to to all use things at the same time, eg if one person is in the shower and someone turns on the hot tap downstairs, are we in trouble? Can 2 people have a hot shower at the same time or will we have to play tag team?

Any advice is much appreciated!

 

[Killy Bing]

The 42 cdi would cope better than the 33he, a combi performance will not be the same as tank fed especially if two outlets are run at the same time.

its likely your hot water is gravity fed from the boiler.
likely meaning if you go for a new system or heat only boiler, the cylinder would need replacing too.
at which point you could go for an unvented hot water system which would be mains pressure.
you would also have the tanks and likely most of the pipe work removed from the loft.

the people quoting should have explained this and asked your opinions on what you would like.

post up on here in the "I'm looking for a plumber" section and request quotes from the forum members.

Personally while upgrading the system i would swap the electric showers for mixers, or just leave them in place as back ups

also as another little note, a combi boiler and unvented hot water cylinders require both good pressure and good flow rate
your installers should check this while quoting.

if you were in my area i would happily give you a site visit and quote!

good luck and happy christmas

 

[northcarr]

The 42 cdi would cope better than the 33he, a combi performance will not be the same as tank fed especially if two outlets are run at the same time.

its likely your hot water is gravity fed from the boiler.
likely meaning if you go for a new system or heat only boiler, the cylinder would need replacing too.
at which point you could go for an unvented hot water system which would be mains pressure.
you would also have the tanks and likely most of the pipe work removed from the loft.

the people quoting should have explained this and asked your opinions on what you would like.

post up on here in the "I'm looking for a plumber" section and request quotes from the forum members.

Personally while upgrading the system i would swap the electric showers for mixers, or just leave them in place as back ups

also as another little note, a combi boiler and unvented hot water cylinders require both good pressure and good flow rate
your installers should check this while quoting.

if you were in my area i would happily give you a site visit and quote!

good luck and happy christmas

Spot on advice.

 

[lame plumber]

if you go for a combi keep the electric showers as back up, just note a combi install will also work out cheaper to install than an unvented cyl swap and boiler change. re kids, I had family of 5 and combis throughout with no issues to mention, its whether you all want baths all the time or can cope with showers, which are cheaper to run!

 

[Leo21]

Our Conventional boiler need replacing and I have had 2 heating engineers come round and they both recommend it being replaced with a Combi. However a quick google has made me nervous that it isn't suitable for us so I'm after some advice please.

We have 4 bedrooms and 2 bathrooms, both will electric showers. 2 adults and 2 young children but who will grow into 2 (maybe more) teenagers in this house. The advice that I have read suggests that conventional systems are better for large households/families but both heating engineers suggest that suitable combis nowadays can also cope fine. The 2 that they suggest are a Baxi Platinum 33HE or a Worcester Bosch Greenstar 42CDi. I understand we have good water pressure.

One electric shower is broken but if we go down the combi route I will get a 'normal' shower plumbed in instead. At the moment, the only hot water we use if for the kids bath every other day and a bit of washing up so they make the vaild point that it doesn't seem worth heating a whole tank for that little hot water use.

My main concern is that if we get a combi, will be be able to to all use things at the same time, eg if one person is in the shower and someone turns on the hot tap downstairs, are we in trouble? Can 2 people have a hot shower at the same time or will we have to play tag team?

Any advice is much appreciated!

As said above, an unvented system would be best. Specially with new showers, the only fly in the ointment will be that it will double the cost of the installation. So basically it's down to how much you want to spend.

 

[townfanjon]

looking long term, IMO you need a 'heat only' boiler and an unvented cylinder. The demand on your hot water in future years could be massive.(not good if you have a combi) But yes as Leo says its going to 'cost'

 

[Ermintrude]

Neither a combi or unvented will deliver two baths at the same time if the water pressure is pants. For two baths at the same time u need a good supply 30lpm at a dynamic 2 bar . I would simply install a new system (pressurised boiler) and upgrade cylinder to double it's current 100l capacity. Install a header for cold and fit a pump for the showers? Think tho a combi would be most economic? Probably my choice would be the Baxi but the 40kw as I believe it out performs the wb and has a better service and life prognosis?

 

[lame plumber]

you could always have a combi for now and when you want a cyl later if required the combi can convert to running a cyl as well.

 

[sheff paul]

Our Conventional boiler need replacing and I have had 2 heating engineers come round and they both recommend it being replaced with a Combi. However a quick google has made me nervous that it isn't suitable for us so I'm after some advice please.

We have 4 bedrooms and 2 bathrooms, both will electric showers. 2 adults and 2 young children but who will grow into 2 (maybe more) teenagers in this house. The advice that I have read suggests that conventional systems are better for large households/families but both heating engineers suggest that suitable combis nowadays can also cope fine. The 2 that they suggest are a Baxi Platinum 33HE or a Worcester Bosch Greenstar 42CDi. I understand we have good water pressure.

One electric shower is broken but if we go down the combi route I will get a 'normal' shower plumbed in instead. At the moment, the only hot water we use if for the kids bath every other day and a bit of washing up so they make the vaild point that it doesn't seem worth heating a whole tank for that little hot water use.

My main concern is that if we get a combi, will be be able to to all use things at the same time, eg if one person is in the shower and someone turns on the hot tap downstairs, are we in trouble? Can 2 people have a hot shower at the same time or will we have to play tag team?

Any advice is much appreciated!

I think you have answered your own question,fit a modest system boiler,and a cheaper end unvented cylinder all will be more reliable and offer better performance than a big silly combi,even with modest incoming cold you will get 2 mixer showers on at the same time.Maybe be more to fit but in the long term far better. Beware of the Combi Queens LOL

 

[lame plumber]

just get a plumber to quote all options and explain the pros and cons. system boilers often cost more than a combi as they sell less of them even tho there are less parts in them, so combi queens can make good economic sense and then you can laugh at those who've been flogged a more expensive option for no real gain

 

[sheff paul]

just get a plumber to quote all options and explain the pros and cons. system boilers often cost more than a combi as they sell less of them even tho there are less parts in them, so combi queens can make good economic sense and then you can laugh at those who've been flogged a more expensive option for no real gain

Just flicked on plumb nation G/worm flexicom 18 sx 700 quid inc flue,RM stelflow 180 around 600 quid = 1300 quid .This compares quite well with a top end combi.I fit/ recommend thease all the time over top end combi's.Still find a lot of fitters have no confidence fitting unvented,hence the name combi Queens.New house builders switched over to unvented years,still find a lot of plumbs on here only fit combi's,a lot of the new fitters cannot do an ''s'' plan so will try and convince customers to have a combi.A 4 bedroom 2 baths with decent water pressure as he states and guys on here are trying to get him to have a combi.Sorry to be controversal but inexperience shows in this thread.

 

[Leo21]

Just flicked on plumb nation G/worm flexicom 18 sx 700 quid inc flue,RM stelflow 180 around 600 quid = 1300 quid .This compares quite well with a top end combi.I fit/ recommend thease all the time over top end combi's.Still find a lot of fitters have no confidence fitting unvented,hence the name combi Queens.New house builders switched over to unvented years,still find a lot of plumbs on here only fit combi's,a lot of the new fitters cannot do an ''s'' plan so will try and convince customers to have a combi.A 4 bedroom 2 baths with decent water pressure as he states and guys on here are trying to get him to have a combi.Sorry to be controversal but inexperience shows in this thread.

Hang on! Most of us have recommended o/v boilers and vented or unvented.

 

[Ermintrude]

just get a plumber to quote all options and explain the pros and cons. system boilers often cost more than a combi as they sell less of them even tho there are less parts in them, so combi queens can make good economic sense and then you can laugh at those who've been flogged a more expensive option for no real gain

Agree a 40kw combi will run two showers no probs u just need Right water supply. Cheap unvented and modest boiler ...... Waste of money. Fit a 40 kW and leave a zone valve on system along with pipework so that an unvented could be installed at a later date if your really unhappy !

Modest unvented my do a bath and a half and have a 25min recovery , so you would need to fill one and then wait decent combi fill one then fill other or fill two at a slower rate ? But all this is irrelevant if you are a Thames water customer . You will be lucky with 2lpm and 1/2 bar dynamic. Unless u live near norther outfall.

 

[sheff paul]

Agree a 40kw combi will run two showers no probs u just need Right water supply. Cheap unvented and modest boiler ...... Waste of money. Fit a 40 kW and leave a zone valve on system along with pipework so that an unvented could be installed at a later date if your really unhappy !

Modest unvented my do a bath and a half and have a 25min recovery , so you would need to fill one and then wait decent combi fill one then fill other or fill two at a slower rate ? But all this is irrelevant if you are a Thames water customer . You will be lucky with 2lpm and 1/2 bar dynamic. Unless u live near norther outfall.

Cheap unvented? they all have 25 years guarantee,40 kw combi = might be going 35mm with the gas,House builders have had this hassle before hence going with the cheaper most effective route.Hate to supply and fit a 40 kw combi then a unvented at a later date.We all know unvented takes longer to do,and fitting a combi is quicker,but when the guy has good cold flow/ pressure.,and is worried about 1 tap combi syndrome would i consider a combi ''hell no sargeant''.

 

[lame plumber]

Just flicked on plumb nation G/worm flexicom 18 sx 700 quid inc flue,RM stelflow 180 around 600 quid = 1300 quid .This compares quite well with a top end combi.I fit/ recommend thease all the time over top end combi's.Still find a lot of fitters have no confidence fitting unvented,hence the name combi Queens.New house builders switched over to unvented years,still find a lot of plumbs on here only fit combi's,a lot of the new fitters cannot do an ''s'' plan so will try and convince customers to have a combi.A 4 bedroom 2 baths with decent water pressure as he states and guys on here are trying to get him to have a combi.Sorry to be controversal but inexperience shows in this thread.

you are making a lot of inaccurate assumptions here youngster

 

[sheff paul]

you are making a lot of inaccurate assumptions here youngster

wish i was a youngster mate,just say it as i see it

 

[Ermintrude]

Cheap unvented? they all have 25 years guarantee,40 kw combi = might be going 35mm with the gas,House builders have had this hassle before hence going with the cheaper most effective route.Hate to supply and fit a 40 kw combi then a unvented at a later date.We all know unvented takes longer to do,and fitting a combi is quicker,but when the guy has good cold flow/ pressure.,and is worried about 1 tap combi syndrome would i consider a combi ''hell no sargeant''.

Decent flow and one tap issue / not in the same house surely ? I have had combi running two showers no issues. Or kitchen tap and shower.

I would suggest a dual input solar unvented every day of week but not always in price range performance feild??

Pressurised system boiler with a decent coil sized open vent or even a parallel open vent cylinder set up might work better as said before and be cheaper than some cheap unvented carp that's constantly loosing its mojo .

P. s. When have house builders ever been a barometer for quality, innovation or performance ? NHBC is more self serving than David Cameron?

 

[Killy Bing]

To the op.
most of the issues that you will read come from people who have come from a cylinder to a 24 kw combi boiler and have expected better performance.

that 40kw combi is almost twice the power, offering much better performance.
if i had a combi that would be the one id fit of the two you have been quoted, however my personal preference is a system boiler and unvented cylinder but that's much more cost and work.

 

[sheff paul]

Decent flow and one tap issue / not in the same house surely ? I have had combi running two showers no issues. Or kitchen tap and shower.

I would suggest a dual input solar unvented every day of week but not always in price range performance feild??

Pressurised system boiler with a decent coil sized open vent or even a parallel open vent cylinder set up might work better as said before and be cheaper than some cheap unvented carp that's constantly loosing its mojo .

P. s. When have house builders ever been a barometer for quality, innovation or performance ? NHBC is more self serving than David Cameron?

Had same problems with top end unvented,and modest ones as a lot use same vessels,valve set up.Incoming pressure/flow dictates performance not how much it costs,wouldnt go for an open vent cylinder with a system boiler ,adding unnecessary tanks if pressure flow ok.NHBC may be carp but dont see many big combi's in 4 bed houses,apart from crap powermax type set up which have had its day.

 

[Leo21]

There are loads of combi,s in four beds around here, a lot of its down to cost. Some people just won't pay the extra, there choice and it's not the end of the world not being able to run two baths at the same time.

 

[sheff paul]

There are loads of combi,s in four beds around here, a lot of its down to cost. Some people just won't pay the extra, there choice and it's not the end of the world not being able to run two baths at the same time.

Yeah cost can be a bigger issue now

 

[lame plumber]

wish i was a youngster mate,just say it as i see it

see where you coming fm you old oldie , but its hard to flog anything more than a 24kw globug at times, hence why I dont get a lot of my quotes

 

[jonnyswamp]

I've got a Worc 42cdi in my house and it copes fine ( me, missus, 3 teenage daughters) one bathroom and a separate shower room, two taps or two showers at once is fine, not ideal with a bath tap and a shower running, but that's not really an issue as a bath can be filled in ten mins
Unvented wasn't really suitable for us, so I went for the biggest combi I could get
Any more bathrooms/ensuites and unvented would probably be the best route

 

[Leo21]

I've got a Worc 42cdi in my house and it copes fine ( me, missus, 3 teenage daughters) one bathroom and a separate shower room, two taps or two showers at once is fine, not ideal with a bath tap and a shower running, but that's not really an issue as a bath can be filled in ten mins
Unvented wasn't really suitable for us, so I went for the biggest combi I could get
Any more bathrooms/ensuites and unvented would probably be the best route

A worcestor though:13:

 

[jonnyswamp]

A worcestor though:13:

Yeah, I know:disappointed:

 

[sheff paul]

see where you coming fm you old oldie , but its hard to flog anything more than a 24kw globug at times, hence why I dont get a lot of my quotes

Look i may have been a bit of a 'Dick' yesterday,thats what happens when you stagger in from a sunday session and pick up the keyboard,and you cannot get any half decent ****,you have to have a rant about something

 

[Nostrum]

3 pages and no one even knows enough about the job to make a good judgement on it!

Personally, with the little info you've given I'd recommend a new boiler which can be a lot smaller than the oversized combi, more efficient as it will be sized according to heat loss (prob 12-15kw for an average size 3-4 house) and a new high recovery vented cylinder and controls. 1 shower on electric, one on pumped gravity feed (may not even need a pump depending on what your requirements are)

Ticks every box, can run the bath and electric shower forever, minimal costs as like for like, back up from electric shower and immersion if your boiler breaks down, no need to worry about flow rates and incoming water main issues and probably the most efficient system out of them all.

youll pay not a lot less for a big combi as you'll probably need a new gas supply to the boiler, all your eggs in one basket if it breaks down and sized for hot water means they aren't the most efficient way of heating your home. You'll pay quite a lot more for an unvented cylinder for possibly worse performance (depending on water main and supply issues) or maybe better performance but in my opinion isn't worth the extra expense for the average household.

why people get so cut up about flow rates is beyond me, everyone's on water meters and trying to save a few quid on the install, but happy to blast twice as much water down the plug hole because they can.

 

[sheff paul]

3 pages and no one even knows enough about the job to make a good judgement on it!

Personally, with the little info you've given I'd recommend a new boiler which can be a lot smaller than the oversized combi, more efficient as it will be sized according to heat loss (prob 12-15kw for an average size 3-4 house) and a new high recovery vented cylinder and controls. 1 shower on electric, one on pumped gravity feed (may not even need a pump depending on what your requirements are)

Ticks every box, can run the bath and electric shower forever, minimal costs as like for like, back up from electric shower and immersion if your boiler breaks down, no need to worry about flow rates and incoming water main issues and probably the most efficient system out of them all.

youll pay not a lot less for a big combi as you'll probably need a new gas supply to the boiler, all your eggs in one basket if it breaks down and sized for hot water means they aren't the most efficient way of heating your home. You'll pay quite a lot more for an unvented cylinder for possibly worse performance (depending on water main and supply issues) or maybe better performance but in my opinion isn't worth the extra expense for the average household.

why people get so cut up about flow rates is beyond me, everyone's on water meters and trying to save a few quid on the install, but happy to blast twice as much water down the plug hole because they can.

i would fit a combi if i could catch his missus in the buff(only if she,s fit)