ideal classic model NF250

mnab

I have an Ideal Standard boiler, model NF250. It is probably 25 years old. It has been running well for the past 9+ years since I lived in the house. Only this summer it needed a new fan, and since then it has been much quiter with no issues since May. The gas bills are relatively low, for a 3bed detached house the annual bill is around £600. I am now considering having a power flush and a magna filter fitted. The idea is to extend the boiler's life and making it more efficient. I am assuming I can still recover the cost of the work (£420) when the time comes to install a new boiler, then I will only need a new boiler with no additional costs of a magna filter and a power flush. I would be grateful for professional advice whether this is reasonable to do to delay having to pay for a new boiler, or if it is a waste of money on an old boiler. Thanks. The system had a powerflush approx. 9 years ago, fluid from pipes has soot and not clear

nofoollikeold

1. Fitting the magnetic filter is a good idea.  It will separate the the ferrous muck (magnetite) out of the system.  The resulting cleaner system may be very marginally more efficient, but I doubt you could measure the improvement.  
2. Power flushing would, again, provide some minor efficiency improvement if your system has a lot of sludge.  However, unless the system is dosed with inhibitor, and running properly so as not to introduce more oxygen via the F&E tank (if you have one) then it will need doing again in a few years.
3. I doubt anything you spend now would represent a recoupable investment. 
4. Your boiler is a good old work horse, and the longer you can keep it going the better.  Assuming it is about 65% efficient, you are "losing" about £210 per annum up the flue.  Take at least 10 years for a new boiler to pay for itself, and by then it would probably need replacing itself!
5. Your best economic strategy is probably:
5a. Fit the filter.  My preference is the Magnaclean Pro.  Fit to the return pipe as close to the boiler as possible.
5b. Add a cleaner such as Sentinel X400.  
5c. Circulate for 2 or 3 weeks with the system running for, say, 2 hours per day.  During this period, check and cleaner filter as necessary, probably hourly to start with, then twice a day going down to two or three times in the last week.
5d. Drain system into a foul drain to get rid of as much muck as possible.
5e. Refill, run and drain system with clean water two or three times.
5f. Refill, add a decent inhibitor such as Sentinel X100.
6. Continue to run system as normal, checking / cleaning filter perhaps once every quarter / half year.

FreeBear

Depending on how the boiler is plumbed in, it is worth fitting a zone valve to switch the heating to/from the hot water tank. No point in having the radiators heating up when you just want hot water - Some of the radiators will get warm even without the pump running.

A smart heating control is also worth looking at - I have an ancient back boiler, and have a "smart" control system. Being able to set different temperatures throughout the day has helped to save a little on gas. It also controls the hot water temperature and shuts the system down during the summer months except for bath night - A big saving there. Looking at a gas bill of around £200-£250 for the year for a 1930s 3 bed semi.

Before you go splashing out on a power flush & magna filter, take a look at the Drayton Wiser system - If you are tech savvy, I'd suggest Home Assistant, but it is a steep learning curve and is not a simple "off the shelf" solution.