Costs of converting conventional boiler to combi

evoke

Any ideas on the costs to convert a contentional boiler central heating system to a combi boiler system? The work would need to include the boiler replacement, new radiators, removing the tanks in the loft and the immersion heater tank. The property is a typical 3-bed semi.

Burridge60

Why do you need new rads?

We had ours done in October. Combi boiler. we had two new rads (choice not necessity) a towel rail in downstairs cloakroom moved downstairs loo rad to old airing cupboard and a new boiler in the loft. Great to have more space to store stuff (no tank) and water pressure to taps after Combi is better than before.

Under £2300

HugoSP

Can't disagree with the above. Though you could probably shop around a bit and get it cheaper.

However a few important points to consider.

1) It will take longer to run a bath with a combi

2) Your current system will have a max pressre of about 0.4 bar. The combi system will be about 3 times that when switched on. Be prepared for your combi to find any weak joints in your plumbing. Our changeover in our last house resulted in an insurance claim due to a corroded pipe under the floor finally giving way.

3) Your old HW tank is probably worth about £40 at the local scrap yard if you strip off the insulation and weigh it in. If you are inclined try to hang onto it and cash it in yourself. The plumber should ask you if you want it. These things have a habit if disappearing from a job without trace. If I'm removing or replacing one I always ask the client if they want it. The answer has always been 'no thankyou' to date, but I have asked.

bob_a_builder

If I'm removing or replacing one I always ask the client if they want it. The answer has always been 'no thankyou' to date, but I have asked

I expect the response could be affected by the way the question is put

evoke

The existing rads seem very old. Would it be worthwhile replacing the old pipework too?

westy23

QUOTE
2) Your current system will have a max pressre of about 0.4 bar. The combi system will be about 3 times that when switched on. Be prepared for your combi to find any weak joints in your plumbing. Our changeover in our last house resulted in an insurance claim due to a corroded pipe under the floor finally giving way.

Good morning
Is the pressure increase only applicable to combi boilers? as i am
considering a valiant system boiler and have a few concerns about some of my pipework.

Same question
any difference in operating pressure between an system boiler and a open vent boiler.
thanks

evoke

andrew-b wrote: »

Why do you want to switch to a combi?

Efficiency, simplicity and to reclaim the space taken by all the tanks (especially the immersion heater tank). Also the ability to have instant water on demand for as long as I need it rather than a tankful.

I'm not 100% of that last benefit as I don't know whether a conventional boiler starts heating water when the hot water in the tank starts running out. My understanding is that you have to wait for another tankful to heat up which takes a long time.

rob7475

Hi,

We had our old floor standing conventional boiler replaced in November.

We had a Worcester Bosch Greenstar 30SI combi installed in a different part of the house. 7 new stelrad radiators installed, wireless thermostat and timer, magnaclean. 5 year warranty on boiler as installer was Worcester bosch approved.

Old boiler and tanks were removed. Work took a couple of days and cost £2400.

Wasn't a bad price IMO.

We got a couple of quotes a few month earlier just to replace the cold conventional boiler with a new conventional boiler and these came in at around £2500 without any radiators.

Hope this helps,

Rob

evoke

Thanks for the pros and cons. The property i'm looking to buy has an old conventional boiler with a hot water tank (plus immersion heater in the tank). They've installed an electric shower so that's fine. The boiler itself is very old but has been serviced and works fine.

I'm caught between having the system Powerflushed and serviced versus replacing all of it with a combi boiler system.

The rads are very old so need to be replaced anyway (and thermostatic valves added to the new rads). I'd like a wireless thermostat too. Would it be better just to get it serviced, Powerflushed and replace the rads and possible the boiler itself or go a combi system?

What I don't want to end up with is having to rip the boiler out in a few years time after the house has been completely redecorated.

Canucklehead

evoke wrote: »

Thanks for the pros and cons. The property i'm looking to buy has an old conventional boiler with a hot water tank (plus immersion heater in the tank). They've installed an electric shower so that's fine. The boiler itself is very old but has been serviced and works fine.

I'm caught between having the system Powerflushed and serviced versus replacing all of it with a combi boiler system.

The rads are very old so need to be replaced anyway (and thermostatic valves added to the new rads). I'd like a wireless thermostat too. Would it be better just to get it serviced, Powerflushed and replace the rads and possible the boiler itself or go a combi system?

What I don't want to end up with is having to rip the boiler out in a few years time after the house has been completely redecorated.

Good afternoon: discuss your requirements/concerns with a RGI recommended to you by a source you trust after he/she has conducted a site survey then choose a system that best meets your requirements/budget. Further advice is available here.


HTH

Canucklehead

markdavey

HugoSP wrote: »

1) It will take longer to run a bath with a combi

This is not my experience. I can run a bath at full pelt (i.e. tap fully open) and the water is always piping hot (too hot to get into straight away). In fact, moving to a combi, I can actually fill the bath quicker as my hot water pressure with a tank was dire.

If it is sized correctly, it shouldn't be a problem.