Ariston EuroCombi SX20 (4711602) Multiple Problems

[NathanM]

I'm not a gas engineer but hope you can help me understand what is/might be wrong with the boiler in the house I bought recently in Bolton. I've found a few posts on this but nothing particularly helpful or conclusive.

The boiler outlet (condensate?) pipe runs constantly with water onto the roof below. It used to drip but now it's as if a tap is running with a low flow. I'm guessing this isn't right....

On top of that, when the central heating is on, it reaches the temp I've set it to on the dial (around 65 degrees) then goes off, then there is a loud clunk a couple of minutes later as the boiler lights again for about 20 secs before going off. Another 2 minutes later and it lights with a loud clunk again - ad infinitum until the timer turns the heating off. The boiler literally ignites every couple of minutes for the 2 and half hours the heating is set to be on in the evening. It's maddening. Again, I'm guessing this isn't right either; not the intrusively loud ignition noise and not the constant on/off cycle we have to endure....

Thirdly, when the heating isn't on there is a very strange whining/howling noise that happens every few minutes for a few seconds. At first i thought this noise was wind howling outside round the back of the house, but it in fact comes from the pipework in the boiler from what i can tell now, and can be heard throughout the house, and is bloody frustrating. Any thoughts?

The pressure reads on/around 3 bar all the time.
The hot water works fine.
The radiators are fully bled (done while the system was off and cold)

Advice greatfully received.

 

[mrgas]

Either your filling loop has been left open or your plate heat exchanger is shot.
Look at FAQs
Sort this out first then look at any other problems.

 

[Corgigrouch]

The howling and the dripping pipe are linked, it's the PRV chattering as water forces it's way past it.. A guess is that your pressure gauge is reading over 3. MrGas has suggested what the problem could be..

I have come across noisy gas valves on these boilers, they operate with a hefty clunk, I guess the only solution is to replace the gas valve.. the rapid cycling on and off may well be caused by poorly adjusted low and high burn settings, could be linked to your clunk...

 

[Gasguru]

Agree, gas valves on these can knock...probably the oil dampening has failed...new gas valve required if you can't bear the noise.

The heating may not have been range rated ie adjusted to suit the radiator load...setup properly should help prevent the cycling and the boiler will be quieter.

Sort out the expansion vessel and replace the safety valve - see FAQs.

 

[mrgas]

could by cycling due to cold water constantly filling up system?

 

[NathanM]

Thanks for the responses fellas. Really very appreciative.

Filling loop? Is that the braided hose with the white knob on it? I've no manual and had no luck searching for one so I'm in the dark on what is what. All I can tell you is that the boiler was off while a load of work was done on the place. Gas and water shut off.

Sounds like I should be able to deal with the filling loop as soon as I know what to close mrgas.

High/low burn settings sounds like something under the cowl that needs checking.

Expansion vessel and safety valve (gas safety valve?), no manual again.

As an update, the boiler when it's lit runs at 3.2 bar, so your estimation of pressure was spot on Corgigrouch.

Anyone know where I can get a manual? And I'm' not having much luck searching the forums for specific info on the filling loop and expansion vessel, so feel rather a lot like a numpty.

 

[Corgigrouch]

Try a google search for an installation manual for your boiler, I think that I found the manual for an ariston somewhere on the net but cant remember where.. Pressure vessel is the large circular red tank on the back of the boiler and the safety valve is also known as the Pressure relief valve (PRV) and is the valve at the bottom of the boiler with the red knob on it and 3 Bar printed on it..It releases excess pressure in the heating system from the boiler. If the tap on the filling loop is open then pressure from the mains will constantly be filling the boiler and could be forcing water past the PRV which vibrates and makes the noises that you hear.. The previous owner could have done a sneaky on you as if the pressure vessel is duff, then they sometimes just crack open the filling loop to ensure that the boiler runs.. which is not good

Setting the gas pressures is strictly for a CORGI gas man

 

[Agile]

If you are going to let this property then you need by law to have a gas Safety Certificate!

A landlord in Ealing was recently fined £15,000 for non compliance with legislation!!!

Tony

 

[NathanM]

Corgigrouch and mrgas I'm happy to tell you that the infernal wailing/howling has stopped following your advice after I closed the tap on what must be the filling loop. This has also stopped the constant running of water from the condensate pipe. And it has also seen the pressure drop from 2.9 bar with the boiler off, to 1.5 bar (Though I've no idea what pressure it should run at.)

It seems that now I need to get the gas valve cleaned/replaced to stop the very loud ignition noise and have the high and low burn settings (which I'm guessing is the same as having the boiler range rated) to suit the radiator load.

Does that soud about right? If so it's time for me to pick up the phone for an engineer in Bolton.....

And I never did find a manual for the boiler, just and exploded diagram of how it's built and lots of other folks looking for a manual too.