Heating Stuck On!

[Smowball]

We had two new radiators fitted on Friday. System drained etc etc.when he refilled it he couldn't get heating to stay on. Didn't make sense as it was fine before he arrived. After three hours of draining , filling, air locks etc he finally got it working and all radiators hot. He left and I turned wall thermostat to zero as didn't want heating coming on in morning as wasn't cold. Woke up and house is boiling. All radiators pumping out heat even tho wall thermostat is on zero. Only way to turn heat off onto manually go into timer and switch whole system off. He can't come bk tilll at least Tuesday so does anyone have any idea what's causing this??

[Old_Geezer]

Broken thermostat ? Or dodgy connection ?
You could surely adjust each radiator separately.

[Smowball]

Thermostat was perfectly fine when he arrived. And yes I could but it's a three storey house so that would be a pain.god knows what he's done

[Old_Geezer]

Might have knocked something. But if he was just at the rads and didn't go near the thermostat nor boiler then it may be simply coincidence.

[Smowball]

No he did go to the boiler, and the cupboard where the timer and pump are

[The Builder]

From the fact that the Heating wouldn't stay on, and then the thermostat not responding, it does suggest a faulty thermostat.

Of course it could be a circuit board fault, but the first thing I would look at would be the stat.

[Smowball]

We did a test. Heating and hot water were on (on timer) and wall thermostat was on zero but radiators still boiling so we turned the hot water off - and radiators turned off. No idea what this means lol

[bhg481]

On our system you can't have the radiators on without having the hot water on, so your last test result is to be expected.

[bhg481]

If your thermostat is the mechanical type should should be able to hear it click as you turn it from zero to max and back again. If it's not clicking it means it's not switching.

[Smowball]

Yes you hear it click but it still stays on even when turned to zero

[Dinapal]

If you have a 3 port diverter valve then maybe it has jammed. They run on a small electric servo motor but can be freed with a manual lever. I am no plumber but I have had issues in the past with ours. (diverter valve)

[Dinapal]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
http://www.ebay.co.uk/itm/HONEYWELL-CENTRAL-HEATING-MID-POSITION-DIVERTER-3-PORT-VALVE-5-WIRE-22MM-V4073-/122359245468

[Smowball]

Ah I see. Interesting...

[Dinapal]

In simple terms the valve is electrically connected to the programmer/timer.The programmer will turn the valve via the electric motor so that you get hot water only from your tank or it will divert the valve to control hot water to both rads and hot taps etc. It is possible,if you have this system, that the diverter valve has remained stuck on diverting hot water to rads and hot taps.
If you look at the link there is a grey square cover on top of the brass valve. There is a protruding handle on the other side which you can move manually.Try moving it back and forward and see if it frees the valve.If the motor has burnt out you can buy just the motor unit and replace it via 2 screws without removing all three water connections.
I will lookmfor a better picture showing the manual handle.

[Dinapal]

http://www.ebay.co.uk/itm/New-Honeywell-V4073-22mm-3-Port-Mid-Position-Valve-Body-Only-/132095804480


http://www.ebay.co.uk/itm/ACTUATOR-HEAD-3-PORT-MID-POSITION-REPLACES-HONEYWELL-for-MOTORISED-ZONE-VALVE-A3-/401147059453

ECT-REPLACEMENT-FOR-HONEYWELL-V4073A1039-/171344198245

1st link shows the brass 3 port valve
2nd link shows valve with motorised unit on top
3rd link shows the manual lever at the side running along a groove at bottom.

Of course I could well be barking up the wrong tree as I said earlier I am no plumber but have experienced very similar issues (twice) which concerned the valve shown.

[Dinapal]

http://www.ebay.co.uk/itm/HONEYWELL-MID-POSITION-3-PORT-VALVE-5-WIRE-22mm-V4073A-GENUINE-HONEYWELL-PART/221335037407?_trksid=p2047675.c100623.m-1&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%

3rd link^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[bhg481]

Dinapal's suggestion sounds a very likely solution. The diverter valve points to hot water in its rest position (so the water heats up before the rads come on) and, if it's sticking, it will certainly lead to the situation you're in. Try his suggestion for freeing it but , if it fails, it's an easy matter to change the operating mechanism as he says. I too have had this happen several years ago.

[Dinapal]

If the electric motor is dud this is the replacement cost.
http://www.ebay.co.uk/itm/SYNCHRON-MOTOR-UNIVERSAL-SYNCHRONOUS-MOTORISED-VALVE-/332025192319

[Smowball]

Ok I'll give that a go. You, and everyone else have been so helpful x

[bentaxle]

TAKE THE TOP PART OFF THE 3 PORT VALVE ITS ONLY A COUPLE OF SCREWS THIS WILL LET YOU GET TO THE SHAFT OF THE VALVE THEN GET SOME GRIPS AND SEE IF THE SHAFT IS FREE IF NOT WORK IT FREE THEN GIVE IT A SQUIRT OF WD ,EVEN IF ITS FREE GIVE IT A GOOD DOSE OF THE WD AT THE BOTTOM OF THE SHAFT

[bentaxle]

Sorry never noticed caps lock on