Central Heating queries

Tahiti

1. Is it realistic to expect to make a 30% saving on your gas bills by replacing an ancient (35 years old) Potteron boiler with a modern combi? The Potterton in question hasn't been serviced in quite some years, and even on full pelt, struggles to heat all the radiators properly.

2. Would it be realistic to have a new central heating system (combi fitted in roughly the same place as the original so no massive relocation issues), and 10 radiators for less than £5k, including the removal of the old system? The house is a 4 bed if this makes any difference, and I'm based in Kent.

I'm really after a reality check before I waste traders times...

EliteHeat

1. Yes
2. Yes

richardw

What about carpets and floor coverings, would they need replacing?

Canucklehead

Hi

More info needed, but I would be wary of fitting a combi to a 4 bed house as the possibility of more than one bathroom is quite high. (Maybe not now but in the future.)
Water pressure and flow rate to support a combi.
Do you really need a new system? I would say it's the system that is struggling to heat up rather than the boiler, but might be restored by a good flush.
You would save heat/money by insulating for less outlay.(eg loft)

Corgi Guy.

Tahiti

Canucklehead wrote: »

Hi

More info needed, but I would be wary of fitting a combi to a 4 bed house as the possibility of more than one bathroom is quite high. (Maybe not now but in the future.)
Water pressure and flow rate to support a combi.
Do you really need a new system? I would say it's the system that is struggling to heat up rather than the boiler, but might be restored by a good flush.
You would save heat/money by insulating for less outlay.(eg loft)

Corgi Guy.

Thanks for the info. There's just one bathroom, and I don't think it's feasible to add another without extending. There's also an unheated toilet downstairs.

You're almost definitely right about the boiler being OK, but it rumbles and at approaching 40 years old, I'm working on the basis it can't live forever (what are the options aside from a combi out of interest?). If it's economical to keep it going, I'm very happy to do so!!

The pipework from the boiler itself is half inch so seems a little on the weedy side, and the system was professionally flushed three or four years back (it may well need doing again though). The rads heat up OK in all but the two back (main) bedrooms (bled in recent weeks, but have never been scorching anyway). It's the original system (with one additional radiator added downstairs I believe) from 1969/70.

Insulation's already on the to do list - done a fair bit in the loft already - and considering cavity wall insulation. The wife's pregnant and starting to worry about the house not being warm enough for the little one.

Seriously - thanks for taking the time to reply - I really appreciate any guidance you can give.

richardw wrote: »

What about carpets and floor coverings, would they need replacing?

Flooring is not immaculate so I'm not too concerned about a few more holes to be honest. The house is more functional than show house at the moment

moneysavingplumber

Is the boiler a floor stander or wall-mounted? I'm assuming if it has 1/2" pipework it is wall-hung (but nothing would surprise me), although I've only generally seen old Servowarm boilers with 1/2" tails with a pump on each return coming direct to the boiler, but wall-hung boilers didn't become prevalent until about twenty years ago. If it's a Netaheat or similar there is a big problem with maintaining it as most of these early balanced and fanned flue boilers are full of asbestos, alot of firms won't even remove the front of some of these boilers now. If it's an old Diplomat style floor stander then they are very hardy and repairable generally as long as the parts remain available. They are grossly inefficient though.

You may not need a complete system replacing, but you will most likely need an update incorporating changing from gravity hot water to fully-pumped and bypass, TRVs fitted with programmer/room stat, new cylinder. I agree with Canucklehead, go for a regular boiler with system update if adding another bathroom is likely.

Tahiti

All I can tell you is that it's a floor standing Potterton (Kingfisher I believe), stood in it's own "boiler room", and it's got 1/2" pipework into a "60" pump (which I believe is the only pump in the system). The boiler is a bit of a beast, and I've been assuming the rads are on a circuit as it's the two furthest from the boiler that don't get hot.

We've got a modern honeywell room thermostat and a timer in the cloakroom - no idea about the rest.

For the work mentioned, are we talking iro £5-600 or more like £15-1600? I'm not after accurate quotes but ballparks would be great. And is there a reason for avoiding a combi on the basis that we won't be adding another bathroom?

From what I've read, longevity does not appear to be a combi's strong point. Would that be a fair comment?

Canucklehead

Tahiti wrote: »

For the work mentioned, are we talking iro £5-600 or more like £15-1600? I'm not after accurate quotes but ballparks would be great. And is there a reason for avoiding a combi on the basis that we won't be adding another bathroom?
From what I've read, longevity does not appear to be a combi's strong point. Would that be a fair comment?

Good morning: My OH, Corgi Guy is out on the tools today, but I do have a few words of advice....
The cost of replacing your current boiler (OH guessed it was Kingfisher;)) with a condensing regular boiler and new HW cylinder (or a combi) is dependent on the site requirements as these can be extremely variable as well as whether the installer follows Best Practice as detailed here
A combi quote, for example, should include:
1. Powerflush (CH system should be inspected first for potential weaknesses).
2. Boiler buddy or Magnaclean
3. Upsizing of gas/cold supply if required
4. Making good old flue hole
5. Removal of old boiler and associated tanks/cylinder/ redundant pipework.
6. Notification of installation to Building Control
7. Completion of Benchmark Log
8. Removal of all waste associated with the installation
9. Mains cold supplied to all outlets eg. shower, taps
10. TRVs/programmable roomstat
11. Scale inhibitor if in a hard water area (eg. the southeast)
12. Insulate HW pipes as required

In our part of Kent, the OH would charge in the region of £3000 for conversion of a conventional boiler to a combi (Vaillant or Viessman): again this is subject to a site survey e.g difficult flue position can add considerably to the cost as can upsizing the gas supply to meet requirements for both the new combi as well as any other gas appliances you have in your home.

In regard to combis... most combis would struggle to supply sufficient DHW for more than one bathroom and would require a good mains pressure/flow rate (that being said, we are combi fans and have one in our own home;)). Bottom line is...a boiler is only as good as its installation and annual servicing

HTH

Canucklehead

janey_uk

I replaced the boiler in my house in the spring of this year. It was a 1960's gas back boiler. We replaced with a gloworm combi boiler in another room, requiring considerable upheaval of floorboards etc. It cost approx £2800 (London prices too).

The house now heats by one degree in 10 minutes instead of the 45 minutes it took before. Radiators are hot in 3 mins from turning on.
The main thing is the gas bills... I now pay per quarter what I used to pay per month!!! (It is actually a 70% saving - we checked like for like against last year's bills and taking summer/winter variation into account). Replacing a really really old boiler brings MASSIVE savings. As I pay by fixed direct debit the gas company owed me hundreds after just a few months!
The boiler will have paid for itself in 2.5 years.

Also, with really old boiler's there is the chance that if they are seem by a CORGI qualified person they may need to be shut off/condemned on safety grounds. Absolutely worth upgrading.

PS. If you don't have one, invest in a gas alarm today!

Tahiti

Thanks to both of you.

We had a CORGI registered CH engineer around yesterday, and he had a fiddle. Reckons the pump isn't working properly and that there's probably a blockage in the system needing a flush, but on the whole, the boiler is fit for purpose. There are a couple of other amendments he recommended, but I'm glad to say he reckons it's safe and functional. Now to wait for the quote for the work (and find out how long to wait to have the work done).

As for 70% savings? Blimey is all I can say to that! You must be one very satisfied customer!!

moneysavingplumber

Pumps often seize at the beginning of the winter, especially on a system with gravity hot water (which you probably have with the pump fitted to the CH return and non-return valve on CH flow) where the pump may not have been used all summer (always a good idea to programme heating to come on for a minute a day in summer with room stat on max to kick the pump).

Your boiler won't ever be condemned on safety grounds based on age alone (unless a famous company with blue vans looks at it :rotfl: ), they are perfectly safe if correctly ventilated, serviced and flued, and are in my opinion safer than some more modern boilers, especially fanned flue models that operate under positive pressure.