Central heating

[johnnybic]

Hi can anyone help when the hot water and heating come on in the morning the rads wont heat up untill the water is hot and this happens any time it needs to heat the water. i,ve got a Y system the 3 way valve is new the pump is ok when its calling for water and heating the valve is in the mid position and the pipe from the valve to the rads gets hot but it just don't seem to circulate the water all round the rads while its heating the water,as soon as the waters up to temp the rads get hot.
Thanks John

 

[seco services]

maybe the cylinder is starving the heating of hot water.
have you a valve on the cylinder return at the bottom of the cylinder ?

 

[stem]

To me, it sounds like you could be missing the 'hot water not required' signal from the programmer, or cylinder thermostat.

This signal supplies mains voltage to the 'grey' wire of the motorised valve, and in conjunction with the mains voltage applied to the 'white' wire from the room thermostat, winds the motorised valve right across from its rest position to the central heating only position.

Or, alternatively when the valve winds fully across to the central heating position only, a switch inside the valve turns on the 'orange' wire that then runs the boiler. (The boiler is turned on by the cylinder thermostat when hot water is required)

If you are competent and safely able to check the voltage on these wires, post back what you find. If not you need to call in someone who can.

Sorry ignore this post, I read the OP the opposite way around and thought the radiators only get hot when the water is on oops seco services idea is much better

 

[johnnybic]

Hi yes it does seem like the hot water is starving the heating but i dont have a valve from the cylinder

 

[Hugh Jaleak]

Try staggering the 'on' times, so hot water is running when central heating if off and vice versa. The cylinder should heat reasonably quickly, then allow boiler to put full effort round the rads.

Long term solution as Seco has said is to fit a valve on the return from the cylinder to restrict the flow through the cylinder and allow rads to get their fair share when both are requiring heat.

 

[johnnybic]

Hi yes what i've been doing is leveing the hot water on all the time. what valve should i fit from the hot water cylinder. do you think my rad system could be starting to block up.
Thanks John

 

[Hugh Jaleak]

Fit a gate valve or lever valve on the return (bottom) pipe where it leaves the cylinder to restrict the flow through the cylinder coil. (Some installers fit a section of 15mm pipe at this point to achieve the same result). If rads are working ok otherwise when HW is off then system should be ok. Water will take the path of least resistance, its far easier to travel through the cylinder than go round the rad circuit and back to the boiler.

 

[johnnybic]

OK i think i'll fit a gate valve but do you think the rad system could be a bit blocked because i can't remember it woking like this before.