What's wrong with my boiler?

[Worried345]

Gas central heating Potterton Nettaheat boiler began to flare in fits and starts rather than stay on this morning. It's now finally died.

Got someone coming out tomorrow to have a look but in the meantime, can anyone knowledgeable suggest what it might be? Will it be days/weeks before we have heating and hot water again?

I'm trying to recover from pneumonia and flu - after over 2 weeks being ill - and am still feeling very unwell - so am panicking a bit about the ice cold house - particularly for the nights - and also for the sake of the DCs.

PigletJohn - really helpful as usual! The WM is in a separate room to any sink. It has one cold water fill pipe straight to the machine that runs through the airing cupboard upstairs and from there to the loft.

The WM drained effectively yesterday but still wouldn't work on any wash cycles including fast or cold wash. I have a horrible feeling it's broken - by coincidence.

Waiting now for service guy to arrive to see if he can fix the immersion heater. Been told by a few places now that it'll be months even before I can get an estimate for a new boiler, let alone a new boiler put in! That's a nuisance.

Would it be worth seeking a firm that is slightly further away from where I live but is one of the Viessman installers from the website list - or should I just find the first company that can fit any kind of boiler asap?

winter will soon be gone

if you can get your immersion heater fixed, the pressure will soon be off and the heating engineers will be twiddling their thumbs when they get back from their Caribbean villas, so you will find it easier to get a quote and installation, and perhaps a "summer sale" price as well.

A good quality installation will be appreciated long after this year's problems have been forgotten.

It sounds as if your WM is fed from the cold water tank in the loft. Do all the taps work?

Well the immersion heater is reconnected, although the water is luke warm for a tiny bath - but better than boiling kettles!

The service engineer told me he could do a boiler installation, outside of his worktime for the company (but on the quiet). He could do this probably within a couple of weeks instead of me having to wait months. He seemed v upfront about everything and suggested i also get other estimates.

I didn't feel he lied about anything but he was saying things about having to upgrade parts of the existing pipework etc to comply with modern health and safety standards and to ask anyone else who did an estimate and that they'd say the same thing.

However, he's not an official installer for his firm. I checked out his Gassafe registration, which he gave me and told me to do and it shows he's a senior enginner who can do the plumbing stuff as well as electrics but he wasn't an installer.

Should I be wary of this - or will he be faster, cheaper and just as good? He said he'd fit a non-combi Baxi Solo unit and flush the system.

Meanwhile, I managed to get the WM working again - not sure why or how but having put it all off and then retried on a 30 min wash, it worked and then did it again for a normal wash! Never thought I'd be so happy about being able to do the laundry!

Baxi is not as good as the other brands we mentioned.

He is right to mention flushing the system, yours is old so is very likely to have a lot of sediment in it. I recommend fitting a System Filter is well which will cost £100+

Your immersion heater will have a adjustable thermostat under the cap. Be sure to turn off the power at the consumer unit before looking. Immersion heaters are far less powerful than boilers so take longer to heat up. You can tell when the thermostat has clicked off, because the electricity meter will flash or turn slower. Immersion heaters are available in different lengths, the longer ones give more hot water but take longer. With luck yours will be a 27" one if it goes in from the top. Some cylinders have immersion heaters going on through the sides, one at the top and one at the bottom, but this is not normal if it is built to be mostly heated by a boiler.

An off-duty installation will probably not be officially notified and might not have the usual guarantees. His employer probably forbids it. He is probably talking about bringing the controls and piping to meet modern energy-saving standards, which are compulsory on a new boiler.

PigletJohn, is it worth looking outside my immediate locality for a Viessman installer who is further away, just to get a Viessman? I only have info. of them from the internet and no recommendation personally.

There is another highly recommneded local installer but he's busy till April and isn't on the Viessman installer list.

Otherwise, there are hundreds of local companies to choose from and I've no idea at all who's good and who isn't.

have a look at the recommended list, it is preferable to have someone who is based with ten miles or so as he is more likely to want to come out and service or repair it when necessary.

I live in a small town and the local person (who had a unit within walking distance) has retired, and the nearest is now about 25 miles away, which is tiresome.

Most people are happy with Vaillant or Worcester Bosch, so keep an open mind. A good local installer makes a big difference.

Where abouts (roughly) are you as I would be happy to suggest a couple of local guys if of any use?

Calling PigletJohn again! I've now had two quotes for a new boiler and wondering which is the one to go for?

The man who said he'd do it 'on the quiet' privately and not through his company, quoted me £2,500 for a Baxi Solo. He didn't give me anything in writing.

A separate company quoted me for a Viessman at either £4,120 for a 100W 34KW boiler or £3,700 for a 100W 26KW boiler. This company have given me a written estimate of everything, including chemical power flush plus inhibitor and various other works to pipework, which will include taking up carpet and floorboards.

Obviously there's a big difference on costs. My gut feeling said I trusted the Viessman fitter a lot more as he spent an hour here today on a Saturday, explained things much more clearly to me, answered questions and volunteered helpful info. about home heating loss etc. But this is a HUGE outlay.

I guess what I'm wondering is is the Viessman estimates are typical, if they include all the works necessary (like different gas pipes, fitting boiler with Magnaclean magnetic strainer, Honeywell 3 post zone vavlve, cylinder thermostat, twin channel programmer for independent control over heating and hot water, new Grundfoss pump and valves, Myson 28mm central heating de-aerator and automatic bypass and all the other main aspects of fitting a boiler)?

He also suggested, at additional cost fitting thermostatic radiator valves and lockshield valves at an additonal cost of £41 per old radiator (there are about 12 I think).

Finally, the company request a 10% deposit with acceptance of estimate and a 50% of balance on commencement of works! Is that ordinary practice?

I am also waiting for a locally recommended installer to get back to me recommending a colleague, as he himself is too busy at present. Would it be worth waiting to hear from him - though I've been waiting a week now and his last message said he hadn't forgotten but was still waiting to see the friend?

All advice much appreciated as usual!

if you are having a hot water cylinder of some kind, I doubt you need a 34kW boiler. Mine is 24kW which is ample for a 3-storey house, though it is modern and well-insulated. Combis, with no hot cylinder, have to be more powerful. I had a 30kW boiler in a 5-bedroom detached Edwardian house.

If your current boiler is adequate to keep your house warm even in frosty weather, measure your radiators. If they are 600mm high, each metre length can provide up to about 1kW of heat. A typical room might need about 1.5kW. Modern condensing boilers run less hot than your old Netaheat so the radiators will not be so hot so will give out less heat. I oversize all my rads a bit so the house will heat faster from cold (often you can do this by fitting double rads of the same length) and have a boiler which is more than big enough.

A modern boiler will modulate its power up and down accordig to demand, so it will try to tick along at a minimum flame size and fan speed, which is quieter and more economical. Mine goes down to 8kW or up to 24kW, I expect yours will have comparable figures.

I've noticed that Viessmann installers seem to aim at the customer who wants a really good quality installation, so they include all the details, and this tends to push the price up, this is not a problem if you want and can afford it. I do recommend the TRVs as well. Is your Viessmann chap on their Approved list, and will he be going the work himself (not subbing it out to someone less skilled, or his lad)?

I'm glad he includes a Powerflush (this is the best part of a days work if done properly so adds £hundreds to the cost) and filter. I recommend the Fernox or Sentinel rather than a Magnaclean (which has a reputation for leaking). Ask about that. A budget installation might omit both. Repiping and a new 3-port valve are good and will bring your system to modern standards. Ask for a Programmable Room Thermostat but not a Wireless one as they are less reliable. Taking up floors and repiping is very labour-intensive.

If your hot water is working now, and (I keep hoping) the cold weather will soon be gone, you don't need to be pushed into a quick decision, summer will be here before the boiler is in. Heating engineers are rushed off their feet in cold weather, and often give discounts when it gets quieter.

You can get a quote from BG or your electricity company; these are almost invariably higher than anyone else will charge, and they will probably offer a Vaillant or a Worcester Bosch, which are both considered good, though IMO the Viessmann is better.

If in future you choose to do it, you could fit a Megaflo in place of your existing cylinder, but there is no need to think about that now.

The deposit is IMO a bit high. Don't pay the 50% before the boiler, controls and all parts have been delivered to your home and you have taken possession of them, they should cost him less than £1500, make it clear in writing that once you have paid 50%, they all belong to you and he can't take them away. See if you can get away with a 25% payment. I paid 10% on order, and nothing more until completion, as I have an honest face.

Do not pay the balance until it is installed and you have seen it working faultlessly for a week, and you want the Installation Certificate to be handed to you in exchange for the cheque (if not before). Tell him this. He should not be surprised or put out.