Vaillant 428

[bizgen]

PLEASE can someone help?
Builders have disappeared for the weekend - don't these things always happen when the weekend arrives?
I know that they did something to the system , draining down or something like that. The chap bled the radiators before he left on Friday, and now I cannot get any heat in any of the radiators.
I have had a look at the display and the radiator symbol is flashing, and in the book it says that means 'anti cycling mode active'. What does that mean? Could that be the reason the radiators aren't heating?
There are two control knobs to the left - the top one is turned to minimum and the bottom one is halfway. It says that the top one is only if the VR 65 is fitted. i don't know whether the VT 65 is fitted or not.
Can anyone give some advice to get me over the weekend as with all the building works going on and new plaster work it gets a bit cold at night. I'd really appreciate it - I'm and elderly lady with some technical ability but not a lot of knowledge of boilers and I don't want to blow the house up!!

 

[gas4you]

Did you have a Vaillant Unistor un-vented hot water cylinder fitted as well?

If you did then you will have a VR65, if you didn't then you will not have a VR65 and the top control will have no effect where ever you set it

The flashing radiator symbol means the boiler thinks there is a call for heat but that it thinks the water is up to temp. Are there any other symbols to the right of it?

Try pressing the reset button for 2 secs (flame with X through it) and report back.

Has it actually worked at all yet?

Also press the i button and let me know what message is in the display

 

[Agile]

I am wondering if the boiler has been isolated from the heating system allowing the boiler to heat itself.

Tony

 

[gas4you]

Yes Tony, that was one of my thoughts that the valves had been left closed.

I would still like to hear what the boiler 'thinks' it is doing though. Can't be that serious as op doesn't seem to be around at present

 

[bizgen]

No, we have a different cylinder.
To the right of the flashing radiator is a round thing with a dot or something similar in it.
When I pressed the i button 2 numbers came up - either 5.6 or 5.1, sorry didn't write it down and have forgotten now.
When I pressed the reset it was rather alarming - A big flame (symbol of flame, not literally) appeared on the left and various other symbols, the boiler fired and the numbers started going up, but then it all stopped again and I'm back to my flashing radiator.
Now my husband is running a bath, the radiator has stopped flashing and there is something like a corn stack to the right of the circle on the bottom of the display.
Does that tell you anything?
Sorry I didn't come back to the website quickly after posting my question - I ticked the box to email me if anyone replied, but that couldn't have worked because I haven't had any emails from the website. That's why I didn't check again - I though probably nobody was around on a Saturday night. Thank you all for showing an interest. I have managed to get a gas fire (new) to work, so had a little bit of heat

 

[bizgen]

Also the big flame is showing again. I don't know if that is because my husband ran the bath or because I pressed the reset button. Although the radiator symbol is no longer flashing, the radiators are still stone cold.
There is a constant sound of running water in the pipes beside the boiler, quite loud and that seems to be there most of the time.

 

[DP]

Boiler does not have isolating valves.

To original poster- I suspect there is an airlock present that is not allowing the heated water to circulate. Pressing the reset button resulted in burner firing and rapid rise of boiler temperature. Now it is sitting idle to await disperasal of heat (that is going nowhere.

Can you feel the two pipes top left and see if they are hot? Be warned these could be very hot. Do you have any motorised valves fitted? If yes, does the valve open? Are the radiator valves open?

 

[gas4you]

The display that you see is actually S1 & S6, yes it does look like a 5

S1 is the fan funning in heating mode and S6 is the fan over run.

The round symbol to the right indicates that the pump should be running, also indicated by the running water noise you can here.

The 'corn stack' as you put it is the symbol to let you know the gas valve is open, I prefer to describe it as an egg timer

With all of these showing and the big flame symbol showing it is proving the boiler is lighting and working ok.

It sounds to me like there is an air lock in the system or it has not been filled completely.

Firstly check the cold fill gate valve in the airing cupboard is open fully and that there is water in the small f&E tank in the loft. If both these are ok then bleed all radiators again until water flows out of bleed nipple.

Switch boiler off by turning on/off knob to 0, wait until display goes blank, then turn back on whilst pressing the + & - buttons together. Hold these together until P0 is displayed. When this is displayed press the i button. This will set the boiler into self purge mode which will take approx 5 mins. Once this has completed boiler will rest at off or rad symbol will appear and it will show the large flame indicating it is on.

Set the programmer to ch only and turn up room stat to full. Shut all thermostatic rad valves except the one closest to pump and see if this gets hot. If it does then open other rad valves in turn and see if they get hot.

Are you actually getting any hot water? If so this circuit appears to be air lock free.

It certainley appears to be something outsdie of the boiler that is causing the problem.

 

[bizgen]

Another strange thing about this house is that the two radiators in the bathrooms are hot when the boiler is programmed for water heating. When I asked why, I was told it was because it is a condensing boiler, and if I turn the radiators off in the summer the boiler will just shut down. But the boiker that was here when we moved was a different older boiler, and those radiators were still hot most of the time. Terrible in summer, if it is a hot one.
Any ideas about this? I had one small radiator in the bathroom of the last house that was on all the time, but I put that down to the fact that I had an Aga that helped to heat the water.
Any thoughts on this?

 

[gas4you]

My thought on this is that the installer has not re-piped the heating system properly. Years ago the bathroom radiators where used as a heat sink to get rid of excess heat when using solid fuel boiler sthat could not be turned off quickly by a boiler stat. Consequently older gas and oil installations kept this and piped the bathroom off of the gravity side primaries that heated the hot water cylinder.

Modern systems should be fully pumped and unless there is a fault all rads should only get hot when ch is selected.

Was this a new boiler on an existing radiator system or a complete new system?

 

[bizgen]

I managed to feel the two pipes at top, they are warm but not red hot.
I am 70 and don't think I can do the loft inspection myself, and I'm a bit nervous about doing all the techie things suggested. I am scared I'll do some damage or blow the place up.
I'm not sure what valves to look for or if I would recognise one, so I may have to tough it out until the men come back on Tuesday.
I don't think our builder is a qualified plumber, but he seems very good at the things he attempts, like putting in the two new bathrooms and running the wastes and things like that. I can see he is a meticulous workman and checks everything. I saw him bleed the radiators and I have tried to check most of them again myself - one or two are done up a bit tight and I can't open them.

 

[bizgen]

It was a new boiler, and previously a new cylinder on an old rad system, with a few new radiators. The radiators that get hot off the water system are new, but have just been connected to the old pipework I suspect.

 

[bizgen]

If those radiators are on a loop from the domestic hot water, I doubt there is much we can do to change that since floors have been tiled over the pipes etc. But if I choose to turn off the radiators on their own isolating valves, will this really cause the boiler to stop working or cause it damage?

You are an incredibly knowledgeable crowd, I am so grateful for all this feedback.

 

[gas4you]

As I do not know your builder I obviuosly cannot comment on his ability with plumbing in rads etc, but it certainly sounds from afar that something has not been piped in correctly or there is a massive airlock somewhere.

I take it the builder had a CORGI enginneer in to fit the boiler?

You are not going to 'blow yourself up' either by following my instructions or doing nothing.

The boiler if fitted correctly will protect its self and as I previously said appears to be working correctly.

I respect the point of your age about entering the loft etc. but feel that you should have been left with a fully functional system, demonstrated to you on its use, or had the system left turned off and informed it could not be used until next week

The boiler will 'stop working' because of this, in fact it is STILL working but has reached the set temperature and has turned its self off until the water cools in it. This will take longer if there is less circulation through the boiler

 

[bizgen]

The hot water system is working fine. This is all work in progress, gradually reaching completion in a few weeks. We are living in a terrible muddle, but see improvements all the time.
The boiler was installed by a CORGI engineer and he will be coming back to drain out and cleanit all out when the place is complete with a couple more radiators to go.
Tomorrow we will go up into the loft and try to find the expansion tank and check the situation and then I will endeavour to do the things you suggest - when I feel a bit braver in the light of day! May I report back again tomorrow? And perhaps you will be kind enough to give any further advice you think necessary?
I really appreciate you valuable time and am quite overwhelmed by your kindness in taking so much trouble to try to help me. Thank you. Gen