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aw007aw · Joined: 27 Aug 2003 Posts: 6 Location: Tyneside

Hi guys - you have a new kid on the block here - please be gentle.

I have a faulty 22 year old c/h system which has a noisy/kettling Thorn Olympic wall mounted boiler - a motorised Honeywell zone valve on the central heating side - a clapped out mechanical Potterton Mini Minder - and a non functioning Grundfos pump on the hot water run to the cylinder - with no cylinder or room stats.

Its a bit of a mad system with no stat control hence hot water too hot & central heating to the 3 double and 4 single radiators not hot enough - in fact its freezing cold now with a dead pump - the hot water feeds 1 bath 1 wash hand basin and a kitchen sink downstairs plus we recently had a new cold water feed electric shower fitted.

Question is - what are the pros and cons of a Combi versus traditional boiler - I've just been quoted £1400 for a Halstead combi boiler only replacement keeping the original rads + microbore.

Thanks for any help or advice.

PS Totally bad day - dead heating system and Newcastle United just knocked out of the Champions League - tragedy. Crying or Very sad

AlanE · Posted: Thu Aug 28, 2003 1:35 pm Post subject:

Sorry I don't understand references to 'Newcastle United' or 'Champions League' are these makes of boilers? or an old manufacturer of toilet pans(!!!)

Combis have almost been hailed as the best thing since sliced bread and probably are BUT ONLY in small one bed flats etc.

What sort of property do you have and how many occupants. Teenage daughters.

Lets know and can then make more relevant comments.

Alan

aw007aw · Joined: 27 Aug 2003 Posts: 6 Location: Tyneside

Hi Alan

Thanks for your prompt reply regarding my heating or I should say no heating problem.

The property in question is a 22 year old modernish brick and blockwork small 3 bedroom detached 2 storey dwelling house with minimal loft insulation no cavity wall insulation and single glazing - all to be upgraded when funds allow.

The family left home a couple of years back leaving just my wife and I rattling around inside - at last I can do my naked hip hop line dancing in peace now.

Daily hot water needs are therefore minimal i.e. normal 2 person usage from a single bathroom/existing electric shower plus washing up etc.

Room volumes are small - 2250 cu.ft. lounge/diner with 1 large 51.8 sq. ft. total area double radiator + 1 small 21 sq. ft. total area double radiator - 700 cu.ft. kitchen with 1 small 21 sq. ft. total area double radiator - 2 bedrooms of 1150 cu. ft. with medium sized single radiators 17.5 sq. ft. total area each plus a third bedroom and bathroom of 625 cu. ft. each with a small single 16 sq. ft. total area and double radiator 17.5 sq. ft total area.

I'm not sure how radiator area sizes are calculated but I calculated the 51.8 sq. ft. double lounge rad by 5.75 ft L x 2.25 ft H x 4 sides and similarly with the single rads - length x height x 2 sides.

I'm just not sure what sort of direction to go with the replacement system - the existing system seems to have functioned for 22 years with minimal problems until its recent demise - should I stick with an updated version of that type of system or is combi the way forward......

Space for the new boiler isn't a problem as it will live in a similar location to the old one in the integral garage - as long as its less than 18 ft x 8 ft x 8 ft. which I assume new boilers are.

Existing cylinder + pipework + rads etc will probably be cacked up but maybe flushable ?

Sorry to go on - but any helpful advice would be appreciated.

Cheers Alan W

AlanE · Posted: Thu Aug 28, 2003 8:08 pm Post subject:

With the hotwater requirements you appear to have perhaps a combi would be a reasonable route to take.

You would need to have the controls part of your heating system updated in order to comply with current building regulations.

Powerflushing your existing system should be considered a must. Not only to remove the existing crud to make the system operate at maximum efficiency but because modern heat exchangers are much more suseptable to damage from this sludge.

Many boiler manufacturers are liable to void a boiler warranty if this failure to flush is a contributary reason for the boilers failure.

Make sure your installer is CORGI registered and that the Benchmark log book supplied with the boiler if fully compleated.

Alan

aw007aw · Joined: 27 Aug 2003 Posts: 6 Location: Tyneside

Thanks again for your reply and advice Alan.

I have a couple of further questions if thats ok - should I be looking for the larger output in a combi boiler manufacturers range - I assume bigger is better i.e. faster + larger output.

I'm not sure about the term powerflushing - the one installer I've had a quote from so far suggested he replace my existing broken pump with a 2nd hand one and putting flush into the system and running it for a couple of days prior to the new combi system installation - thats not powerflushing is it ?

Finally is it good practice to keep my existing rads - they appear ok externally but I'm aware they corrode internally even though I believe a corrosion inhibitor has lived in the system for the last 22 years.

I'll also make sure its a CORGI installer and that the benchmark logbook is completed.

Cheers again AW

thescruff · Moderator Joined: 03 May 2003 Posts: 4756 Location: Bath

Without hi-jacking the thread.

Ask a few friends and neighbours if they know a good heating engineer, even Corgy don't guarantee a good job.

Get two or three quotes and tell them exactly what you want and what you expect, keep at least 50% of the price back until the paperwork, etc is completed, and tell them you intend to, if he chokes on the tea cup get someone else.

scruff. Cool

aw007aw · Joined: 27 Aug 2003 Posts: 6 Location: Tyneside

Thanks for the advice Scruff

At this point in time there are at least 4 neighbours in a similar position with flaky ageing heating systems - probably due to the houses and heating systems being of a similar age and with some recent cool weather central heating being switched on for the first time in months.

I'll keep your advice in mind though when the next estimates are done - which will have to be very soon as there's not much worse than a cool wife for bending your ears.

Cheers AW

AlanE · Posted: Fri Aug 29, 2003 6:33 am Post subject:

Alan - secondhand pumps!! NEVER. Think of the cost of a pump and the cost of replacing it. How long is the plump going to be guaranteed and is it in perfect condition now. (Slightly different situation where thescruff is concerned as he deals also with large industrial installations where pumps could be reconditioned.)

Powerflushing involves draining the system and pumping the cleaning solution around the system with a dedicated piece of equipment. All the rads except one is turned off and flushed. Another is then turned on while the first is turned off. Each rad is therefore cleaned seperatly. There is a risk that rads might leak following this treatment but less so in your case if inhibiter has been present.

The higher the combi boiler output then the higher the hot water flow for a given tempreture rise. Manufacturers qoute their outputs in litres per min @ 35degrees temp rise. Bear this in mind - during the winter when the mains water is colder - it is not hot water @ 35 deg. it's 35 deg. higher than the cold water in. If you have say a 15 lit/per/min boiler and want the tempreture higher you can always not turn the tap on so far.

If you are going to get several quotes I would suggest you choose a boiler and make a list of all the work you want carried out. Then give this list to each installer and ask for a quote on that boiler etc. This way you can easily compare like for like. If each installer quotes on different boiler this is impossible.

Alan

aw007aw · Joined: 27 Aug 2003 Posts: 6 Location: Tyneside

Hi Alan

I now understand that the installer I spoke to wasn't taking the powerflushing route to clean my system.

The 2nd hand pump that the installer suggested was only a short term measure to enable my old system to be flushed out as my existing pump is dead - this 2nd hand pump would be removed after a couple of days when the old boiler / pump / valve etc. was taken out and the new combi system was installed.

Thanks again for your advice regarding boiler outputs and quotations etc. which I'll keep in mind when getting quotes in.

Cheers AW

AlanE · Posted: Fri Aug 29, 2003 7:23 pm Post subject:

If your pump is faulty, boiler will kettle as no circulation.

A stupid question maybe!! BUT

If system was powerflushed to clean it and a replacement pump fitted do you really NEED a new boiler?????

Alan

aw007aw · Joined: 27 Aug 2003 Posts: 6 Location: Tyneside

Hi Alan

Unfortunately the boiler has been kettling for several months - in fact it must be for well over a year now when I think about it - during which time the central heating and hot water has worked fine - so I can only assume the pump was working okay during that time as well as the rad warmup was fairly rapid.

At this point in time I still have hot water in the cylinder as the boiler seems to heat it without the pump working but all the rads are stone cold.

I suppose the powerflushing + new pump may be an alternative I could have put to the installer who was supposed to be quoting today - but he didn't even bother turning up or ringing me.

The search for a solution goes on.

Cheers AW