Replacing old back boiler

[vanhulle]

Hi there, I've an ancient back boiler powered gas central heating, low pressure water tank system. The rads are 1950s jobs and the whole system, whilst working doesn't seem to ever get hot enough other than to give background warmth. Up full the thermostat never clicks off (25 degrees).
So I guess a new system is required.
Should I go for large combi or boiler and high press water tank? I've been quoted £4300 for combi but £5750 for open vented system.
It's a large 3 bed semi with bathroom and ensuite shower room, 10 rads in total. We're family of 4 but kids are small.
Any help would be most appreciated.
Many thanks.
PVH

 

[stem]

That's a difficult question. There are advantages and disadvantages associated with the different types and much of it is personal choice and what's important to you. A bit like choosing car, everyone will have a different preference.

the good news is that all new boiler types are available in 'A' rated efficiency.

I'm surprised of at the price difference you mention between a combi & open vented. Are these from the same company and for the same scope of work? (for example is one replacing the radiator pipe system, the other retaining it)

A combi doesn't need a hot water cylinder and the cold tanks in the loft, which is an advantage on a new build but, not so much if they are already there. You do gain the space the cylinder occupies but you loose an immersion heater as a back up.

Combi's give instant hot water, but you need to make sure that they have sufficient capacity to heat water for two bathrooms, especially when like now, when the incoming mains water is very cold.

Sometimes the gas supply to the boiler needs to be upgraded for a combi as they need a lot of gas to heat cold mains water instantly.

You say the kids are small, but I can't imagine that you'll be thinking of changing the system again before they grow up to be bathroom hogging teenagers .

 

[powell30]

Baxi now make a band A back boiler with front electric fire. This may help keep down repipework and labour costs.....

 

[vanhulle]

Both quotes are from the same company and are the most competitive of the 4 I received. Both systems require complete new rads aand pipes. I too was surprised as the seemingly the only difference seems the open vented cylinder which is about £700.
The quote for the new back boiler was a lot more.
I guess if I got a 35kw boiler, the bathrooms will cope.
Any further advice (incl if the quotes seem too high) would be helpful.
Many thanks,
PVH

 

[stem]

As you already have an open vented system, I had expected an open vented solution to be cheaper, as usually the cold feed tanks, hot water cylinder and controls can be retained and less pipework changed, than with the combi option. However, re-reading your post again, If your cylinder and tanks are original and from the 1950's they will need replacing. They cylinder could even be an outlawed. primatic type. And your controls maybe clockwork

 

[namsag]

Since when where primatics outlawed ,

 

[stem]

Do they comply with builing regs and can you still install one now? If so my apologies & I stand corrected.