Central heating not working correctly on valiant boiler

[metronome]

I have an issue where by my central heating will not turn on, however I am able to occasionally able to get it to switch on through some coaxing by switching it on and off alot. The hot water comes on just fine and there is no issues with that.

The system is pressurised to 1.7 bar (different to the pictures).

When I click the button (the left of the two holes in the panel to the left of the dial with the numbers on it, refer to image 3) it makes a firing up noise when the boiler is running (what is this button called?) and I think that this helps bring it on.

I also sometimes try leaving the hot water running as well when I'm trying to get the central heating on as it would seem that it doesn't fire up the boiler with the central heating is switched on. The heating then stays on between 1 - 4 hours, sometimes it operates in the right way for about a week. Most of the time if it is working it will only come on when it is using the timer and not always on.

Does anyone have an idea as to what is the problem and how to get the heating to come on when it's meant to and not when it "feels like it"?

Or can anyone at least identify the model of boiler it is?

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• metronome
• 5 Oct 2009
• 1

Untitled

• metronome
• 5 Oct 2009
• 1

Untitled

• metronome
• 5 Oct 2009
• 1

 

[lsxit]

Are you sure its not on contract with British Gas, thats a british gas sticker on the front of it

 

[kevindgas]

looks like a Sine18 to me.
been obsolete for a long time now. some spares are available but not many.
new boiler time i think.

 

[metronome]

Are you sure its not on contract with British Gas, thats a british gas sticker on the front of it

I reckon that's whom the last owners must have purchased the boiler from originally.. I don't have any contracts with British Gas. However how long are the warranties on these things meant to last, just in case there's a chance that it hasn't elapsed?

 

[ROSSGR]

The warranty probably ran out about 18years ago......

Good chance the weep pipes/hydraulic lines are blocked up causing delayed reactions

Time for a new boiler, wasting money repairing this boiler

 

[Prof.plumb]

Nonsense. This is a Vaillant, 242 or 282. Most parts are available for this boiler. Just need a competant heating engineer to look at it for you. If hot water is working fine it is probably an issue with diverter valve not moving into heating position.

 

[mickyg]

most likely the water valve is sticking. The pin on top holds the servo in the hot water position. This would result in the boiler firing up for central heating, but not circulating to the rads. You can try pushing down the servo on the side as in pic. see if it then works.

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• mickyg
• 12 Oct 2008
• 2

 

[kevplumb]

View media item 8355 servo valve from the front

 

[bengasman]

Quite sturdy boilers these, but they do suffer from the little pipes getting blocked. Probably needs a clean and a flush, and sticking a magnaclean on it wouldn't hurt either.

 

[twgas]

try sticking some water in it first, it often helps !!!

 

[kevplumb]

When I click the button (the left of the two holes in the panel to the left of the dial with the numbers on it, refer to image 3) it makes a firing up noise when the boiler is running (what is this button called?) and I think that this helps bring it on.

overheat stat

is the auto air vent open above the pump

methinks you might have a point tw

 

[holty]

think twgas has proberbly looked at the pics and seen what the prob could be.

 

[kevplumb]

The system is pressurised to 1.7 bar (different to the pictures).

 

[holty]

darn. missed that bit.

 

[Agile]

The first thing to try is as Mick says, if the DHW demand pin is retracting and the switch returning to its rest position.

Tony