Best type of boiler Combi v Standard

Jimmy1000

We are currently having an extension built which will contain an ensuite. We have been advised by the electrician that it is unwise to have a second electric shower as this could overload the system when other electrical equipment is used and would blow the main fuse. We have therefore decided that the second shower on the first floor of the extension will take hot water direct from our boiler. Currently we have a standard boiler with a hot water tank on the floor in the airing cupboard on the first floor. The questions I would like to ask is as follows:
Would it be wise to take hot water for the shower from the hot water tank of would the gravity pressure be to low?
Should we replace our boiler with a new combi boiler?
And finally as a supplementary question we have a back boiler located in an open fire place (which is used only occassionaly)and is of course currently connected to the water tank which would no longer be required if we went for a combi. Would it still be safe having a fire with the back boiler still in place provided the pipework was left vented or would the back boiler have to be removed?

ChrisR · Posted: Wed Jan 31, 2007 12:46 pm Post Subject:

It's a compromise.
Bin the boiler and gas fire (they go together). Put a new boiler and unvented hot water system in, possibly needing a new mains pipe. £5-6k should sort it. Easy to say, heh?

And get a better electrician...

tryitandsee · Posted: Wed Jan 31, 2007 2:20 pm Post Subject:

In my humble opinion;

If the central heating boiler is serviceable, working ok and not very old, why change it. The back boiler in the fire gives you free hot water when alight, why change that.

If the water pressure to the new shower is not adequate from your original hot supply, just add a pump.

Not being particulary good at electrics, can't the Electrician run a separate supply to the new shower from the main board. The electrician I bet, just wants to get on the upstairs ring main for ease and go home early.

Good project, will keep you occupied for a few weeks. Good luck.

JohnD · Posted: Wed Jan 31, 2007 2:33 pm Post Subject:

Have you got two bathrooms, or a shower and a bathroom? I am not very keen on combis. If you have several people in the house all wanting hot water at the same time, it will have to be shared between them, but a cylinder can cope with everything except running two baths at the same time (it will run out of hot water and have a delay while it heats up again). There are also other kinds of hot water store available at greater cost.

The electrician is probably calculating that electric showers take (say) 40 Amps each. Your house will be on a 60A or 80A or 100A main fuse, so you can expect to blow the supply fuse if you are using e.g. electric cooker or heater at the same time. No matter how skilful the electrician, he can't upgrade the electricity company's supply to your house (unless you pay many thousands and they dig up the road for a bigger cable).

Jimmy1000 · Posted: Wed Jan 31, 2007 3:27 pm Post Subject:

Thanks for all your quick responses. JohnD you are correct that the electrician advised against going for a second electric shower unit due to the main fuse only being 60A and gave the same reasons as in your response. We only have one bathroom with bath, sink and electric shower and the new ensuite will only have a shower enclosure and basin.

If I stay with a standard oil boiler rather than changing to a combi I assume that as the shower will be higher than the hot water tank that a pump would be required in order to give enough pressure through the shower.
Any suggestions on the best pump on the market?

JohnD · Posted: Wed Jan 31, 2007 4:09 pm Post Subject:

The pressure depends on the height difference from the cold tank (presumably in the loft) and the shower outlet.

Jimmy1000 · Posted: Wed Jan 31, 2007 4:54 pm Post Subject:

I'm no expert so will need some guidance about current system. We have an insulated tank sitting on the airing cupboard floor in the bedroom and in the attic there are two square plastic tanks, one small and one medium sized which I have always asummed were to do with the central heating side of the system. Am I correct in my assumption?

Our current oil boiler is a Worcester Danesmoor 15/19 which is about 11 years old and the tank in the airing cupboard also has an electric emersion heater fitted.

Paul Barker · Posted: Wed Jan 31, 2007 8:16 pm Post Subject:

JohnD wrote:

The electrician is probably calculating that electric showers take (say) 40 Amps each. Your house will be on a 60A or 80A or 100A main fuse, so you can expect to blow the supply fuse if you are using e.g. electric cooker or heater at the same time. No matter how skilful the electrician, he can't upgrade the electricity company's supply to your house (unless you pay many thousands and they dig up the road for a bigger cable).

I agree, don't sack the sparks he has got it right having studied your usage done the diversity and concluded you can't have any further load. He is a GOOD electrician.

You can use a Trevis Boost shower with the existing hot water system in the new shower for cheapness. Combine with new regular or system boiler if you desire removal of back boiler.

Glow worm allow us to decommission a back boiler but the fire can remain in use. I haven't asked BaxiPotterton if they approve of this as it hasn't come up in my work.
If you

bster · Posted: Wed Jan 31, 2007 8:46 pm Post Subject:

tryitandsee wrote:

... The back boiler in the fire gives you free hot water when alight, why change that

eh?

__________________
I am newly qualified, so don't rely on my advice get a second opinion!!!

gavinda · Posted: Wed Jan 31, 2007 8:51 pm Post Subject:

maybe thinking of the old coal fire brass block back boilers..... but coal aint free

bster · Posted: Wed Jan 31, 2007 8:52 pm Post Subject:

i think you are right

__________________
I am newly qualified, so don't rely on my advice get a second opinion!!!

ukboilerman

Jimmy1000 wrote:

We are currently having an extension built which will contain an ensuite. We have been advised by the electrician that it is unwise to have a second electric shower as this could overload the system when other electrical equipment is used and would blow the main fuse. We have therefore decided that the second shower on the first floor of the extension will take hot water direct from our boiler. Currently we have a standard boiler with a hot water tank on the floor in the airing cupboard on the first floor. The questions I would like to ask is as follows:
Would it be wise to take hot water for the shower from the hot water tank of would the gravity pressure be to low?
Should we replace our boiler with a new combi boiler?
And finally as a supplementary question we have a back boiler located in an open fire place (which is used only occassionaly)and is of course currently connected to the water tank which would no longer be required if we went for a combi. Would it still be safe having a fire with the back boiler still in place provided the pipework was left vented or would the back boiler have to be removed?

Try and go for an eco friendly boiler. ]

Moderator 11 · Posted: Mon Jun 09, 2008 9:20 am Comment:

Please note rule 9 (Please do not use excessive quoting in your posts.) - See here for the forum rules.
-
you seem very fond of that website but it is not permited as contact details and/or free advertising. So if you keep putting it in I will keep removing it.

please review Forum Rules

D_Hailsham

ukboilerman wrote:

Try and go for an eco friendly boiler. There is lots of information about the energy ratings for about 4000 ****** ] on this boiler insurance website:*******

You obviously did not notice that this topic was current in January 2007

Not surprising if you were awake at 0552 this morning.