central heating not working on thermostat..

[codek]

Hi,

We had a plumber in about 6 months ago who fitted a new radiator. At the time when we re-filled the system it took a long time to get going and in the end he moved the lever on one of the electronic valves to force the heating to come on. So that meant that when hot water was on, heating was on too.

anyway i then put the lever back into normal position out of override and all seemed fine - the heating was off, the hot water was on, it was summer, all was good.

The problem now is, that the heating no longer comes on via the thermostat. So it works if i go back into the override mode, but thats not much use as it's just on and off!

I wonder if anyone has any ideas of anything i can check or do before I call a heating engineer in? I had a problem with a pump once before and was able to fix it thanks to advice in a forum, so fingers crossed!!!

Thanks!
Dan

 

[fredplumb]

Hello

I believe if you have a 3-port mid position motorised valve. If the Heating comes on when only the manual lever is pushed across (so it is open to both hot water and heating) then it seems as if the motor has failed inside of it.

You can either change the motor, which has 2 screws and 2 wires, or replace the whole actuator head if it is easier.

Worst case scenario, change the whole valve.

 

[codek]

yes, there's 2 motorised valves. Why 2? I'm curious and would like to learn how it works - i understand the basics of it, and how the boiler and coil in the hot water tank bit work!

Could the refill of the system have caused the valve to break? I guess so...

 

[fredplumb]

it is hard to work out the exact fault without seeing it properley.

you say you have 2 valves?

and the heating only comes on when you push the valve on the heating circuit across?

of this is the case then the motor isn't moving across properley and turning on the pump and boiler (the connection / switched live is not being made).

 

[codek]

yes of course, i can understand that, no 2 systems seem to be the same!

but yes, 2 valves, i dont know which circuit is which tho. but when i push the lever and lock it into position on one of them, we get nice and warm!

just a lot of pipes!

 

[shambolic]

yes, there's 2 motorised valves. Why 2? I'm curious and would like to learn how it works - i understand the basics of it, and how the boiler and coil in the hot water tank bit work!

Could the refill of the system have caused the valve to break? I guess so...

One valve controls hw other controls heat to rads. The power comes from clock to room stat them to valve. This will be on the brown wire usually (dependant on valve make but we will say honeywell for now).
As the valve opens it moves a ball inside the pipe allowing the flow of water to rads but it also makes an "end switch" this sends power from the grey wire over to the orange wire thus bringing on the pump and boiler to supply heat.
At the moment the switch will be made by the hw valve when cylinder stat calling for heat. And the heating valve in flushing position will allow the water to pass through to rads. Unfortunately when the hw cylinder stat is satisfied it will close end switch and the heat will go off too.
You would need to tset for power to the heating valve on the "brown" wire.
If there is power there (again Honeywell) you could change the Synchron motor (a 5 min job) or a sunvic or acl valve the whole actuator head needs replaced again pretty straightforward just do it wire for wire and you cant go wrong.!

 

[codek]

ok i'll do some diagnostics.

Actually thinking about it, it could also presumably be the room thermostat signal not getting through i guess (?). So i'll check that as well.

oh; and the box where the wires go does say honeywell! so thats good.

 

[shambolic]

Just check power into room stat and then power out or link out the stat through the live and switched live.
Most stats click if they have power to them.
If your 2 valves are silver boxes they are more than likely honeywells!

 

[fredplumb]

yes, there's 2 motorised valves. Why 2? I'm curious and would like to learn how it works - i understand the basics of it, and how the boiler and coil in the hot water tank bit work!

Could the refill of the system have caused the valve to break? I guess so...

One valve controls hw other controls heat to rads. The power comes from clock to room stat them to valve. This will be on the brown wire usually (dependant on valve make but we will say honeywell for now).
As the valve opens it moves a ball inside the pipe allowing the flow of water to rads but it also makes an "end switch" this sends power from the grey wire over to the orange wire thus bringing on the pump and boiler to supply heat.
At the moment the switch will be made by the hw valve when cylinder stat calling for heat. And the heating valve in flushing position will allow the water to pass through to rads. Unfortunately when the hw cylinder stat is satisfied it will close end switch and the heat will go off too.
You would need to tset for power to the heating valve on the "brown" wire.
If there is power there (again Honeywell) you could change the Synchron motor (a 5 min job) or a sunvic or acl valve the whole actuator head needs replaced again pretty straightforward just do it wire for wire and you cant go wrong.!

the poster has 2, 2 port valves so the hot water calling or being satisfied won't affect the other valve'soperation. seems like a faulty motor in his HTG valve.

 

[shambolic]

yes, there's 2 motorised valves. Why 2? I'm curious and would like to learn how it works - i understand the basics of it, and how the boiler and coil in the hot water tank bit work!

Could the refill of the system have caused the valve to break? I guess so...

One valve controls hw other controls heat to rads. The power comes from clock to room stat them to valve. This will be on the brown wire usually (dependant on valve make but we will say honeywell for now).
As the valve opens it moves a ball inside the pipe allowing the flow of water to rads but it also makes an "end switch" this sends power from the grey wire over to the orange wire thus bringing on the pump and boiler to supply heat.
At the moment the switch will be made by the hw valve when cylinder stat calling for heat. And the heating valve in flushing position will allow the water to pass through to rads. Unfortunately when the hw cylinder stat is satisfied it will close end switch and the heat will go off too.
You would need to tset for power to the heating valve on the "brown" wire.
If there is power there (again Honeywell) you could change the Synchron motor (a 5 min job) or a sunvic or acl valve the whole actuator head needs replaced again pretty straightforward just do it wire for wire and you cant go wrong.!

the poster has 2, 2 port valves so the hot water calling or being satisfied won't affect the other valve'soperation. seems like a faulty motor in his HTG valve.

It will effect whether his heating comes on or not due to the end switches. I always advise of this if the heating valve is faulty and left on manual. It will not power up the pump or boiler it will only allow water to flow through it.
This is done by the hw valve opening and making the electrical switch inside opening the valve manually wont make the switch so the hw valve must be calling for heat too or you get no heating.
What usually happens is that you get heat for about 30 mins until the cylinder is warm the hw valve then closes breaking the 240v to pump and boiler. Yes the ch valve will be opening but sod all heat will be passing through it
I never said anything about the other valve effecting the valve operation if you read it closely

 

[shambolic]

Ps I didnt know s0d was a bad word as in s0d all heat will pass through it!!!

 

[D_Hailsham]

yes, there's 2 motorised valves. Why 2? I'm curious and would like to learn how it works

First Lesson!
You have what is often called an S-Plan system. Study the diagrams below and you will learn how they work. (click image to enlarge)

There will be a test next week (multiple choice - so it will be easy)

View media item 71






View media item 72

 

[poolebybirth]

It will effect whether his heating comes on or not due to the end switches. I always advise of this if the heating valve is faulty and left on manual. It will not power up the pump or boiler it will only allow water to flow through it.[/b]



i haven't read through all of this post, BUT why would pushing the manual lever arm across NOT put on the pump and boiler. it is doing the same job as the motor would be doing, only if the motor has failed and is not moving, then doing it maually temporarily will surely start the PUMP / boiler?

 

[Softus]

i haven't read through all of this post, BUT why would pushing the manual lever arm across NOT put on the pump and boiler.

Because (a) it isn't designed to do that, and (b) it isn't constructed to do it.

it is doing the same job as the motor would be doing

No it isn't.

only if the motor has failed and is not moving, then doing it maually temporarily will surely start the PUMP / boiler?

No it won't. And don't call me surely.

 

[gas4you]

Perhaps he meant surley Softus