I have a Vokera combi boiler (excell SP 80) which is probably around
12 years old. Lately is has switched off for no apparent reason. Even though I have managed to switch it back on, what would you recommend to do : have it repaired or changed?
Other question, when I asked for quotes to have it changed, the plumber told me that the gas pipe is too narrow and the gas pipes leading to the boiler need to be changed. This would entail major work, so my question is : shy should I have wider gas pipes fitted?
so they can make money out of you. Thats what too many BR are for now. Not the intention, but sure is the result. Clearly it works as it is. "Well guvnor, because of the faulty paintwork on your boiler you need a new one. And to fit that we gotta replace the water tank, all your rads, move the boiler, new gas line in, etc etc." I kid you not.
thanks for all your answers so far, much appreciated. the issue looks like an ignition problem. Surely there should be a way to clean or change the burner / hob ?
Do you mean the pilot light goes out and you have to relight it or is the boiler shutting down suddenly whilst firing or is it an electrical switch off?
Replace it? Thats like saying I need a new car the tire is leaking air. Gas line to small he says. Thats like saying your tires are to small even though they came with the car new. What is important is the amount of flow of gas and if you didnt have enough you would not have had enough heat on the coldest days. Gas flow is measured with a Manometer in the US. The man says its Major work to replace a gas line. One man can pipe a flex line and pipe a house in hours, with pipe in a basement, well if its a 100 ft it might be a 4-8 hr job depending on how often his cell phone rings. You need an honest pro.
Modern combis need a 22mm pipe to deliver the volume of gas they require. Surely not for debate. You wouldn't wire a house in cable too small for the current!
A new condensing boiler is more efficent and uses less gas. If a load calculation is not done then nobody will know if wasnt oversized, Mine was oversized by 75%. I had 120000 BTU, with a load calculation I know I only need 55000, smaller units, need less gas. OP doesnt mention a cold home. Salesman want you to buy the biggest, it makes Them more money. 22mm doesnt mean anything, it is what the boiler consumes and length of pipe run and competing apliances. You dont guess on boiler size you get a proper load calculation done, you dont guess on gas, you measure it. If house has any insulation upgrades and the old boiler is oversized, a smaller unit that demands less supply will work. Non of this is guesswork, its all math the salesman must do and give the customer in writing, if the customer is smart enough to know how real pros do things. Oversize, waste gas by running cold and to short a period at the boilers highest efficency, short cycle and wear out the boilers controls prematurely. It heats now, it has enough gas to heat, new boiler will use less gas, supply is not an issue.
Yes, but the comment was wrt combis - which most installations use
- where the sizing is determined by DHW requirements. If you are going to run baths you may well need a combi that is larger than the boiler it replaces.
25 years plus if a Magnaclean filter is fitted on the return pipe to the boiler. The stainless heat exchanger will last as long as it is not gunged up. It has small tubes in it, so the filter is essential. Make sure inhibitor is added every 4 years (1 can). If using X-100 then no need to drain, just add. Inhibitor can be added via the Magnaclean filter. Cleaning of the filter one a year and adding inhibitor is a DIY job. As long as running parts are available it shopuld go on and on.
The boiler I am using is 23 kW combi and I live in a one bedroom flat. It is at the very least nicely dimensioned. I run baths without problems, and can heat the lat and run hot showers / hot baths in the same time with no problem. So say if I replace the boiler I don't think I would need a more powerful one, hence my wondering about wider gas pipes. Also the comment about checking the gas pressure makes total sense to me, just wondering if this is a UK standard practice. From what I have read so far it seems that installations are driven more by rule of thumb than measuring.
To answer Heliotrope's question, the pilot light goes off and I need to relight.
Thanks to all for your contributions, and Happy New Year!
Replace it? Thats like saying I need a new car the tire is leaking air. Gas line to small he says. Thats like saying your tires are to small even though they came with the car new. What is important is the amount of flow of gas and if you didnt have enough you would not have had enough heat on the coldest days. Gas flow is measured with a Manometer in the US. The man says its Major work to replace a gas line. One man can pipe a flex line and pipe a house in hours, with pipe in a basement, well if its a 100 ft it might be a 4-8 hr job depending on how often his cell phone rings. You need an honest pro.
Oh to have a basement (don't get me going on this) In the UK most pipes are fitted when the property is at a basic stage of build. The routing is convenient at the time and bloody difficult afterwards.
I believe flow calculations need to take bends into account.
No I don't do that. It has swiched off a couple of times, and in each case it was when the thermostat was at a rather low setting (15C) given that it's winter here. Not sure if there is any relation though.
No I don't do that. It has swiched off a couple of times, and in each case it was when the thermostat was at a rather low setting (15C) given that it's winter here. Not sure if there is any relation though.
Things appear to be ok on those points and it should make no difference what the thermostat setting is.
It would appear to the thermocouple playing up. A universal Tc can be had from the sheds at low cost and are quite easily fitted so long as you feel easy about DIY work.
You can download the instruction manual from Vokera website for your model.
The reason why a better gas supply pipe is being suggested is that the existing (whilst it works) is probably not the size required by the regs. If the installer gets caught out installing/using a pipe that is undersized he will have to improve the pipe at his own expense.
The regulatory setup here, in the UK, is quite different. Flexible pipes for gas are specialist, not widely available and generally not used in the UK.
The problem is that even if it currently works with the wrong pipe the regulations are being enforced much more closely than they used to be. An honest pro does not want his registration put on the line just to save the customer a few hundred quid.
thanks for your contribution. I have found the commissioning paper for this boiler, and it was commissioned in sept 1998. So the gas installation was deemed appropriate and my boiler is about
10 years old, not 12. Have the regulations changed over the past 10 years? Do those regulations mandate pipe diameter? (maybe they do I don't know, just haven't been able to find that type of information)
No change in those regs. Tighter enforcement all the while and especially after 2005. Might or might not be OK. Would expect to need at least 22mm and 28mm if over 10m. A very short length of 15mm /might/ be OK.
15mm is OK if meter directly by boiler.
You need 18 mbar gas pressure at boiler when going full tilt on /all/ gas appliances.
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