Central heating on the fritz

[Droogs]

Hi guys,
looking for a bit of advice. Yesterday my good lady turned on our heating as she was a bit cold but after half an hour noticed it hadn't come on. I had a look and noticed the boiler hadn't kicked in. so, i had a play about and discovered, that the heating wouldn't come on on its own but does when I turn on the water. As soon as the water is turned on the boiler will fire up and heat both. I have one of the standard little white boxes with the LCD display that British Gas put in with 2 buttons, one on either side of the display.

Just wondering if anyone can suggest why the heating side has suddenly pack in working on its own.

thanks
droogs

 

[AndyT]

You probably have a three way electric valve which opens up the flow of hot water into the radiator circuit. Try watching it when you turn the CH on - you should be able to see and hear it opening.

If it's more complicated than that you will need a proper heating engineer, not me!

 

[mind_the_goat]

If you have 2 values it could be the switch in the one that opens the heating circuit could be faulty, or a faulty wire in the same circuit. The switch closes closes when the valve is open so the boiler knows it's safe to fire up.

 

[jimmy_s]

It sounds like its a system boiler? - If your hot water is working ok then it must be the control cct on the heating side. It could be the end switch on a control valve (could be a 2 or 3 port valve) or it could be the relay in the programmer or possibly a room stat if there's one fitted.

Do you have a multimeter?

 

[Droogs]

Cheers guys.
Seems the valve for the hot water makes a whirry noise but the CH one doesn't. I think it may be from what you have said is a loose wire to the CH valve as theres a fair few wires on a board next to where she keeps her shoes. so will check it out. There's no room stat fitted on our system. will pop into the workshop tomorrow and grab my multi-meter and check out the readings

 

[MMUK]

If it's a 3 way valve at fault then you have my sympathy. It will only be the beginning - they will fail regularly. I went through four in the space of three years up in Blackburn. **** design for a C/H system.

 

[jimmy_s]

Sounds like the motor on the 2 port CH valve is away. You should find a lever on the back of it with any luck so you can open it manually, that would make the contacts on the end switch of the valve and allow the boiler to run if the CH programmer is "on"

Jimmy

 

[Droogs]

Cheers Jimmy will try that

 

[gwaithcoed]

Hello droogs, does your heating valve look like this



and with the cover removed like this



then it is likely that the motor has failed like this




The valve shown here is a two port Honeywell and the motor for it can be got from Toolstation for£13 - 43. The motor will also fit valvesACL Draytona Tower Landis & Satchwell

It's easy to change ensure the power is off to the boiler, remove the valve cover and release the motor which is held in with one screw. Cut the wires connecting the motor (two wires) and remove the motor. Reinstalling the new motor is a reversal of removing.
Ensure the new connecting wires are insulated.

If it's a 3 port valve I cannot help as I have never worked on one.

The number for the Toolstation motor is 68222. I know because I've just had one delivered

Hope this is of some help.

Alan.

 

[Racers]

I have changed a couple of motors its easy to do, and it sounds like its your problem.
Sniff the valve to see if you have that burnt smell.

Pete

 

[Random Orbital Bob]

It's the synchro motor in the valve exactly as the last 2 have said. I've just done mine....easily the most common fault in CHS followed by the pump breaking. Band aid is to move the lever manually and allow it to come to rest in the little cul-de-sac off the main track. In that position it's permanently on but rads wont be on as long as the boiler is switched off by either the room stat or the timer controller. It does mean whenever the pump is on your rads will steal some of the hot water. So if you have a condition (in your controller) set for hot water only and no rads you will get both until you replace that synchro motor.

 

[jimmy_s]

Alan

If its a Danfoss valve you have, I have a couple of these kicking about in the garage still in their boxes, you can have one of them if its going to fix your problem.

Jimmy

 

[Droogs]

hi Jimmy not had a chance to check yet been away from home. Will do so in the AM and give you a call
Cheers