Vailent Sine 18 not igniting

[HowMuch!!!]

I just had a young engineer have a very quick look at the boiler and he said he thinks it is the igniter and he won't be able to get the parts, I am not sure if he just didn't want the job or the hassle of looking. About 5 years ago I had a different problem (the flow switch) with a sililar response. I had paid a one off payment to BG who said they would fix it for that fixed fee whatever the problem was. A contractor not in a BG van but had his own company name on it turned up, he took one look at it and condemmed it and left. I researched the problem found a supplier a few miles away with the part, bought it and it cured the problem. And got a refund from BG which more than paid for the repair.

The current symptoms are; when you turn the tap or heating on the main burner does not ignite, you can hear the pump start up and run. I have left the boiler off for over an hour including the pilot light off and I have pressed the black rubber reset button on the side with no change.

He also said that due to regulations and that the supply might not be good enough to not get an error on a new boiler, I would have to have a thicker pipe as the one in use is 15mm. The gas meter is at the front of the house and the boiler at the back so it would cost a lot to run a thicker pipe around under, over or through the house or move the boiler closer. I have seen posts that there are boilers that will still run on 15mm pipe. There are no other gas appliances in the house. I was even thinking of getting a second hand boiler that would work on 15mm if a new one is not possible. Just before this happened I had noticed the water pressure was 3 bar and I flicked the release valve and dropped it to 2 bar. Maybe the hot weather?

If it can be repaired I was going to semi retire it and change the water to electric. In fact I am going to do this even if a new boiler is fitted and get a boiler for heating only.

 

[ianmcd]

the start of your post says it all, "a young engineer" get someone who knows the boiler and they will sort it, these old boys are bombproof if you know what you are doing

 

[Gasguru]

The size of gas pipe is dictated by the gas regulations not by diyers on here...a maximum 1 mbar drop is permitted from meter to boiler. Simple.
If you've only got a 15mm pipe from front to back it's woefully undersized and MUST be upgraded. The size of gas connection under the boiler has NOTHING to do with the pipe size. I suspect your pipe is 22mm under the floor. The pilot would struggle to stay lit once the working pressure at the boiler dropped to such a low level if on 15mm.

A boiler for heating only will cost the same as a combi and your hot water bill will treble.

There's a well known Vaillant repair business in London but even they might now have stopped working on Sines....the last one I fixed was installed in 1982 but I think they date from 1979.

 

[HowMuch!!!]

Thanks for the quick replies.
Yes, I deliberately put a "young engineer" in as the boiler is probably older than him and I have been looking at finding an engineer that has experience with the Sine 18 boiler. I posted the job online and he replied the next day, the only taker so far but it has only been up there for 3 days.

As for the water heating bill I have been looking at instant water heaters (no tank) that promise to be cheap to run plus a home made solar water heater I want to experiment with to raise the cold water feed temperature to them in the winter. I have a hot water Myson blow heater in the conservatory connected to the heating that in the summer and sometimes winter the sun heats the water inside it so much that if you leave the hot switch on the thermostat clicks on and the blower starts, and it heats the in/out pipes for a few feet as well. But that is a project for the future. I need to get the boiler fixed or replaced first ready for a change in the weather. If the price is the same then I may as well get a combi as the hot water feed could be shut off if not needed. Having it for heating only will make it a lot easire to relocate it.

 

[HowMuch!!!]

The size of gas pipe is dictated by the gas regulations not by diyers on here...a maximum 1 mbar drop is permitted from meter to boiler. Simple.
If you've only got a 15mm pipe from front to back it's woefully undersized and MUST be upgraded. The size of gas connection under the boiler has NOTHING to do with the pipe size. I suspect your pipe is 22mm under the floor. The pilot would struggle to stay lit once the working pressure at the boiler dropped to such a low level if on 15mm.

A boiler for heating only will cost the same as a combi and your hot water bill will treble.

There's a well known Vaillant repair business in London but even they might now have stopped working on Sines....the last one I fixed was installed in 1982 but I think they date from 1979.

The house dates back to the 1930's maybe earlier if that helps. I can see the larger pipe from the meter going under the floor but I can also see the last 2 metres of pipe to the boiler is 15mm and there is another metre at least going down to the floor although it has been covered by a surround, this is directly underneath a 15mm pipe capped off upstairs in the bedroom so I guess it was for a gas fire upstairs or gas to start a coal fire that has been removed, a bit too late for gas lighting I think.

 

[durhamplumber]

can see the larger pipe from the meter going under the floor but I can also see the last 2 metres of pipe to the boiler is 15mm and there is another metre at

That is a bit different to 15mm back to front!

 

[HowMuch!!!]

A boiler for heating only will cost the same as a combi and your hot water bill will treble.

I just found these figures for when they were new, so I think my hot water bill must be a lot higher than it could be now and if I use it for hot water if repaired. I will be going for electric instant hot water heaters (no tank).
Boiler ID* 4704401
Fuel mains gas
SAP 2009/2012 annual efficiency (%) 65.0
SAP winter seasonal efficiency (%) 66.0
SAP summer seasonal efficiency (%) 57.0
Comparative hot water efficiency (%) 44.5
SAP 2005 seasonal efficiency (%) 65.0
Efficiency category estimated (ie SAP default)
SAP equation used
Output power (kW) 19.5
Final year of manufacture 1988

 

[HowMuch!!!]

I came across a manual and I wasn't even looking for it. There are bound to be more people looking for one at some point as I have seen some ask on here.
http://acwilgar.co.uk/Boiler-Manual-PDF/Vaillant/VCW Sine 18 20-1 25-1 T3W.pdf

I would like to know how old it is.
The Serial number although it says Fabr (Fabrication?) number is 19396619

 

[gas112]

prob around 1983

 

[HowMuch!!!]

I had another engineer (25 years experience?) look at it, again no diagnostics. He tried to open the top cover like a door then didn't bother opening anything, so obviously does not know this type of boiler. He said all boilers are the same when I asked if he had worked on one before. No engineer will admit to not knowing the Sine 18 T3W before arranging a visit which I am getting fed up about. He said it was a totally different problem to the other engineer. Then went on about a new boiler.

He also said the conservatory roof was too close to the flue and that would stop it working properly. We moved here in 1998 and it has worked with only the following two problems. From moving in the hot water only worked with the CH on (flow switch) which we put up with for quiet a while as we had the same problem with finding an engineer to fix it. Then the presssure release valve started leaking and both parts were replaced when I sourced the flow switch locally as the first engineer had said you can't get parts. Both fixed no problems since then till now. So I would like it fixed as it has been a very reliable boiler.