No heat to radiators. "Little white box" not working?

Mayo Exile

Had a couple of radiators on yesterday to dry some clothes. Noticed after a couple of hours that they had gone cold even though the boiler (natural gas) was still going. Looked in the water tank cupboard and saw there was no light on the white box (arrowed). It was cold to the touch. Always seemed to be hot to touch before this. I turned the timer turned off at night as I was suspicious about it. Thought it might be a fire risk.

I'm guessing this is the cause of radiators going cold. What does this box do? Who should I get to look at this, plumber or electrician? Apartment is a new build, only in since December last.

Joey the lips

Check and see if you have hot water. Its safe to turn the boiler on dont worry. i am prity sure your zone valve is stuck in hot water mode. if its a new build this should not happen so easy. its a classic sympton of cheap valves,

If the light is not on it can be something simplt like the fues to the switch is only gone though.

Micky Dolenz

On one side of the box, there will be a lever, push this lever to one side and you will hear it open. nce the lever is over all the way, push it down into the little grove. This has manually opened the valve.

This is a treatment of the symtom. The cause will still need to be found.

Mayo Exile

Joey, there was hot water. But I'm not sure when the valve went faulty, so there could have been hot water in the tank before valve went on the blink.

Mickey Dolenz: I'll check for this later on. At work now. Plumber or electrician to fix this, if something is wrong?

Joey the lips

Mayo Exile wrote: »

Joey, there was hot water. But I'm not sure when the valve went faulty, so there could have been hot water in the tank before valve went on the blink.

Mickey Dolenz: I'll check for this later on. At work now. Plumber or electrician to fix this, if something is wrong?

Like I said it might be just a fuse so would not require an electrician. A safe bet is a plumber as nearly all the time its the valve and not the electrics. believe it or not the plumber will only change the head at first. This is something you can do quite easy just find the valve make and buy a new head excluding the valve

It might save you a call out charge

tbh if the house is that new the builder should be checking this!

Mayo Exile

tbh if the house is that new the builder should be checking this!

Thanks Joey. Yes, I believe they are still around the estate alright. I'll take a look.

Mayo Exile

Hi guys. I moved the lever all the way the over to the right and the light came on. It was originally over on the left. So its powered up I'm guessing. Fired up the boiler and the radiators are heating.

However now the boiler stays on even with the timer off. This is the manual overide on the valve ignoring the timer, yes?

Need someone to have a look now?

Micky Dolenz

There is a micro switch in the box that bypasses the time clock. So when you manually opened it it came on.

Check your room stat, if it is set too low, it won't come on, since it is quite warm now, it may be as simple as turning up stat on wall.

Mayo Exile

Thanks Micky D. The room stat is at about 18 degrees C. Thats cooler than current outside temperatures me thinks. Should I put lever on the valve back over on the left in it's original position?

Micky Dolenz

Ya, just let it out of the grove and thats that.

Mayo Exile

Couple of hours ago I put the wall stat up to about 26 degrees C. Seemed to work. Valve activated (light came on) about 15 seconds after timer turned on.

All radiators bar one heated up. Its the same one that wouldn't work a few months ago. Had been fine since then up to now. Turned off system and let it cool down. Bled radiator, but no air in it, it seems and it still isn't working. .

Micky Dolenz

Mayo Exile wrote: »

Couple of hours ago I put the wall stat up to about 26 degrees C. Seemed to work. Valve activated (light came on) about 15 seconds after timer turned on.

All radiators bar one heated up. Its the same one that wouldn't work a few months ago. Had been fine since then up to now. Turned off system and let it cool down. Bled radiator, but no air in it, it seems and it still isn't working. .

When you bled it did water come out?
are you sure both vavles on on?

Mayo Exile

When you bled it did water come out?
are you sure both vavles on on?

Yes. Both on. Water came out of radiator. Turned all the other radiators off and the radiator got hot. Bled it again. Some air came out this time. All rads seem ok now.

However the water pressure has dropped on the gauge. Might need to repressurize system. Not quite sure how to do this? Need to turn on black knob at side of gauge plus red stopcock? Which one first, or just one or the other of them?

Joey the lips

The pressure will need to be checked when cooled, Although I know how to do it i would not like to advise you on how to re pressureise as its not a safe one to get wrong. Check the pressure when totally cooled and if its below the operating pressure the boiler wont work. The plumbers on site will re pressurise it in 2 min.,

Micky Dolenz

The pressure looks ok, but as Joey says, check it when it's cold. Even then it should be grand at what it is.

Mayo Exile

Thanks for the replys chaps! I'll wait till tomorrow to check again.

Joey, I don't mind! Feel fully free to tell me how to do this job should you wish to. Your advice is genuinely appreciated.

Mayo Exile

Pressure has dropped to about three quarters of a bar. It should be about 1 bar when cold shouldn't it? Would need to repressurize to this level? How to do it?

Micky Dolenz

3/4 of a bar is still ok.

You have an automatic filling valve, turn the red valve slowly and see if the needle rises. VERY IMPORTANT. never leave water rise unattended or the pressure will increase and your system won't like it. So even if you have to vent rads, Do so only when valve is off I.E fill it then turn off, vent and repeat as many times as needed.

Joey the lips

Micky Dolenz wrote: »

3/4 of a bar is still ok.

You have an automatic filling valve, turn the red valve slowly and see if the needle rises. VERY IMPORTANT. never leave water rise unattended or the pressure will increase and your system won't like it. So even if you have to vent rads, Do so only when valve is off I.E fill it then turn off, vent and repeat as many times as needed.

This is how i do it, Make sure the system is cool and as for automatic filling valves. These should be BANNED! they hide leaks theyt do not repair them! Combi filling loop is the way to go! and correct procedure is to disconnect the loop after but no one does!

If you have a combi filling loop which is a braded hose. the screw is located at 12 and 6 o clock. Open it veryu slowly to 11 and 5 o clock have someone watching the pressure rise on the boiler.

Note the operating pressure on the boiler and stop when it reaches the min.

Lastly do all this when the system is cooled.

Warning you increase the pressure to much and at the very min you will blow the safety valve!

Be very Very careful!

Micky Dolenz

Joey the lips wrote: »

This is how i do it, Make sure the system is cool and as for automatic filling valves. These should be BANNED!

+1, spent time in the UK and they have been banned from there years ago.

Mayo Exile

Hi guys. Thanks for the further replys. I opened the red wheel, and there was no change according to the gauge. Please note that the picture is from last night, so shows the reading when the system was on. It was about 1.1 bar then. This is the gauge by the combination hot/cold water cylinder. What does the black knob on the side of the gauge do?

The pressure on the boiler itself is about 0.2 bar and has always been this as far as I can remember. Dodgy gauge? I think its a system boiler.

At work now so can't do anything more till this evening.

Micky Dolenz

Your as well off to leave it alone, the pressure @ 3/4 bar is within acceptable range.

That black knob turns the filling valve on and off.

Mayo Exile

Cheers Mickey D. Yes I'll think I'll leave it alone alright. If it ain't broke don't fix it!