Old boiler advice - replace or not

ratechaser

Hi all - first post on this part of the forum and looking for some advice... my details:

Boiler: Ideal Mexico Super 3 RS 100 - as per picture. Age: at least 16 years (when we moved in) but can see a 1997 date stamp so maybe 23/24 years.

House: 3 storey 1950s detached, 16 rads (~50:50 mix of big old cast iron ones and newer slim ones), 3 full bathrooms with separate bath/showers. Megaflo system, installed 6 years ago when loft was full converted.

Fundamental question - does it need replacing

Considerations

1) Reliability - never actually broken down. Gets an annual service from British Gas (the only people I can find to cover an old boiler) and every year they suggest replacing it, but then they would wouldn't they. Point being, do I replace proactively or wait for it to conk out, probably in the depths of winter, when it's needed most? From the little I've been able to read on this boiler, there's a view that it is a very reliable and well made model...

2) Efficiency - we're currently consuming about 52,000kWh a year in gas, which seems high to me, even with children that don't understand that you don't need more than 10 mins for a shower! I think there is more we can do around pipe lagging, and the mish mash of rads we have has been called out as inefficient, but leaving that aside, would a newer boiler with the same power/capacity make a noticeable difference to consumption? Currently paying over £200/month for our dual fuel tariff, so it's not insignificant...

3) If replacing, what would be the best type - I ask because when I look at Boxt, it's suggesting a combi, which I didn't think would be appropriate for a Megaflo system, or for that matter any big/high consumption household? I would have naturally assumed a conventional floor standing boiler would be the right replacement. Space is not a problem (it has its own room), and obviously it would be easier in terms of pipework, especially as it's asbestos lagged a little further up (painted and in good condition so that's no immediate concern)

4) Pressure - suspect this isn't a boiler consideration but will throw it in - despite the Megaflo, the shower in the top floor bathroom loses a lot of pressure if either of the ones on the floor below are in use. Is that more a question of how the pipes coming out of the hot water tank have been arranged? As far as I'm aware you can't pump from a Megaflo given it works from mains pressure (which we have been told is good in our area)

This has turned into a bit of a long post so thanks to anyone that's made it this far, and all advice/suggestions are welcome - happy to provide more info if needed. And if it's as simple as "that's a great boiler, they don't make them like that anymore, leave well alone and it should keep going for years", then I'll happily take it!

Thanks
RC

grumbler

I wouldn't -  because of (1).

(2) - it will take decades to recover the cost of a new boiler through slightly better efficiency.

tacpot12

I think you should keep the Mexico going as long as you can. The chances are that when it needs replacing it with either be because it needs mechanical part that can't be sourced, or due to a leak. It might be worth buying any parts that typically wear out when you can find them on eBay at a good price, e.g. fans and pumps.

Set a reminder in you phone to check the boiler thoroughly for leaks around April/May. This will give you time to find a installer and get the boiler replaced over the summer if it needs replacing. A new boiler might be use 20% less gas than your current boiler, so you can use this to figure out how long a new boiler might take to pay for itself. 

I would recommend a system boiler to replace the existing boiler you have. I had a Intergas boiler fitted last year and have been please with the choice so far. The Intergas HRE SB 30 model would be the direct replacement for your boiler, although this boiler is wall mounted, rather than floor standing. 

I can't help with the pressure question. 

Grenage

I would also stick with the boiler; I have an old Potterton that's over 20 years old and it's an absolute tank.

clive0510

we had a problem with the boiler here. about 8 maybe 10 yrs ago. kept losing its pressure. we had new expansion valve fitted. after that the pump went , internal thermostat was playing up, change over valve,and something else. in the end virtually everything that was changeable was changed. at a total cost of just over £600. 
ever since then never had a days trouble with it, just have it serviced once a year. 
so in answer to the thread title maybe its worth leaving the boiler where it is, and just keep it going as long as you can.

Jeepers_Creepers

Hi 'Chaser.

As others have said, there's no point changing the boiler until you need to - the outlay will be more than any energy saving. When you do come to swap, then go 'system' so that you lose that small F&E tank in the loft.

Your rad system will need a darned good clean at the same time, and it might be a good move to get the ball rolling on that sooner rather than later. You will need a magnetic filter fitted at the time of the new boiler, so why not chuck one in now?! This will start to clean out your system so half that task is taken care of. (Add long-term cleaner too).

A separate issue is your hot water from the megaflow. That's almost certainly the best system for your large house, so I wouldn't look to swap from that. It's no real surprise that the top floor's shower has less flow since it's fighting gravity. Also, even with a Megaflow, the output from the taps will only be as good as the cold mains that's driving it, so if you open more than one tap there is almost certainly going to be a drop in flow between them all. You either live with that, or fit isolating ball-valves to the lower showers and tweak them shut a small amount (to reduce the flow to them to your chosen maximum!), or else - ultimate solution - fit an mains water accumulator to provide an extra amount of supply to your house. This can go in a garage or perhaps in the same room as your boiler. It essentially stores a few hundred litres of water under pressure ('mains' if it's strong enough, or by a pump if not) and this will then supply as much water as you could possibly want to your multiple showers!

Belenus

Old boiler advice - replace or not?

I've been thinking the same.

Eventually I decided that. although her looks are fading,  she is still a decent cook and divorce would be expensive.

ratechaser

Thanks all, some very helpful comments and advice. Must admit that I'd never really heard of a 'system' boiler before and I didn't even realise that we still had a feeder tank (it's been tucked into the eaves behind one of the new bedroom walls). 

Sounds like a magnetic filter is a no-brainer, although 5 minutes of google research suggests that a deaerator might be an even better option. We'll be due a service around May (which would hopefully identify any potential leaks anyway) so will see what BG quote for the work, then laugh at them and get it done independently...

Now I think about it, I think the system was powerflushed 6 years ago when the additional rads and pipework for the top floor were installed...

As for pressure, I had heard about the accumulator option, might be a bit of a squeeze in the boiler room (unless it was done as part of fitting a new wall mounted one), but part of me does like the idea of throttling pressure on the downstairs showers as they are the ones that my children use!

Anyway, the main point being that you've confirmed my own thoughts that I should leave the current boiler well alone while it's still working well. Probably got another 10 years in this house so will cross fingers that it outlasts us!

coffeehound

Having a rough stab at the numbers, if your gas was 3p per unit, then 52,000 units would be £1,560 per year.  Your boiler had at best less than 73% efficiency when new (some web sites seem to indicate 66%) -- no idea how that might change with age.  A new boiler could be 98% efficient so might save you ~£400 or more a year in gas.  However since you would be running it above the condensing return temperature for some of the time in order to heat the megaflo to 60, that would blunt the new boiler's efficiency for some of the time.

neilmcl

Given the costs involved it's rarely cost effective to change an old, but working, boiler for a new one.

Jeepers_Creepers

Yes, if the current boiler is still working fine, it would be silly to swap it. As soon as you are threatened with a genuine large repair bill (and I mean 'genuine'...), then you can look into a replacement. These old boilers are pretty basic units, so very little to go wrong.

I think Coffee's efficiency ratings are ambitious; I can't see any new boiler - unless installed in a careful tailor-made system - realistically achieving anything close to 98% eff when installed to an existing system. For max eff, I guess you'd be talking a completely underfloor heating system running at below 30oC or similar.

Yes, of course, it will be more efficient than the old boiler it replaces in an existing system, perhaps 15% or so as a guess? When- if - you do come to replacing it, make sure that any rads that also need replacing are sized for max efficiency, which basically means 'oversizing' them. By fitting 'larger' rads - either width or extra panels/fins - you will get the same heat out of them as before, but running on cooler water. A cool return temp is what provides the efficiency for modern boilers.

The reason I suggested a mag cleaner now was because I assumed  - from what you said - your existing rads could well be suffering from decades of light corrosion and sludge build-up. Pleased to hear you had it 'flushed, tho', so hopefully most of that is taken care off. You'll almost certainly still need one tho'...

The two devices mentioned perform different tasks; a Mag Filter is there to catch (so it can be removed) magnetic sludge, usually stuff that was there historically, but also as a protection for any new stuff that could form. The 'deaerator' is designed to simply remove dissolved air from your system water. By changing to a sealed 'system' boiler - with no F&E tank open to the elements, so nowhere for air to get in - you will have handled the 'air' issue pretty much completely. With added inhibitor to prevent internal corrosion,  you shouldn't have any future issues. The small amount of dissolved air in the system's initial fill will soon be removed by the boiler's auto air valve.