Has anyone got any ideas. When the hot water is calling for heat and the room stat is off the rads still get hot. Once the hot water is back up to temp the system works fine. If i check the 3 way valve operation by turning to turning the room stat down i can here the vavle operating
3 Port Valve / Thermostat Problems
- Thread starter andy-man
- Start date
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It sounds to me like the valve is not fully closing the central heating port when heating is not required. Here's my reasoning.
The 3 port valve normally sits in the hot water open position with the valve pulled by a spring so that the central heating port is closed.
Assuming central heating is not required, when hot water cylinder thermostat switches on it starts the boiler and water from the boiler flows around the hot water cylinder. The position of the valve does not change.
In your case somehow it looks as if water is managing to pass the valve. The valve could be faulty, for example the spring is not fully returning the valve to the central heating closed position, the spindle is partially siezed, or there could be something trapped inside the valve preventing it closing fully.
This assumes the valve is installed/wired correctly, which if it has been working OK previously is most likely.
Once the hot water is up to temperatue and the central heating thermostat comes on, the valve motor will pull the valve across so that the hot water port is closed off and the central heating port is open. At the same time an integral microswitch switches on the boiler. When the central heating thermostat switches off, the boiler also goes off, so the radiators will cool whether the valve has completely closed or not.
That is until the hot water thermostat switches back on again.
The 3 port valve normally sits in the hot water open position with the valve pulled by a spring so that the central heating port is closed.
Assuming central heating is not required, when hot water cylinder thermostat switches on it starts the boiler and water from the boiler flows around the hot water cylinder. The position of the valve does not change.
In your case somehow it looks as if water is managing to pass the valve. The valve could be faulty, for example the spring is not fully returning the valve to the central heating closed position, the spindle is partially siezed, or there could be something trapped inside the valve preventing it closing fully.
This assumes the valve is installed/wired correctly, which if it has been working OK previously is most likely.
Once the hot water is up to temperatue and the central heating thermostat comes on, the valve motor will pull the valve across so that the hot water port is closed off and the central heating port is open. At the same time an integral microswitch switches on the boiler. When the central heating thermostat switches off, the boiler also goes off, so the radiators will cool whether the valve has completely closed or not.
That is until the hot water thermostat switches back on again.
S
Soggy_weetabix
has it just occured recently, or has it always like that?
could be reverse circulation
put the only heating on, and feel which pipe underneath gets hot first. Turn off, leave to cool and then put only hot water on. If the other pipe gets hot first, you have reverse circulation. If its the same one, replace the motorised valve.
David
could be reverse circulation
put the only heating on, and feel which pipe underneath gets hot first. Turn off, leave to cool and then put only hot water on. If the other pipe gets hot first, you have reverse circulation. If its the same one, replace the motorised valve.
David
The 3 way valve was replaced arround September 2006, and everything seemed fine. The room stat failed early November and was replaced. The old stat was a mechanical one with a 2 wire connection the new one is electronic with 3 wires so i had to run a neutral from the terminal box to the stat. The system seemed fine until Christmas, we had a house full it got very warm so i turned the stat down. We then found the rads kept hot.
Fiddle arround the next day i found that the heating stayed on when the hot water stat was calling for heat. I had not noticed any probs before but is it possible something to do with the room stat.
Fiddle arround the next day i found that the heating stayed on when the hot water stat was calling for heat. I had not noticed any probs before but is it possible something to do with the room stat.
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You can test the room stat and its wiring, if you have and are able to use a multimeter. When the room thermostat is on, or calling for heat, the white wire to the motorised valve should be live (230v). Turn the thermostat down until it goes off and the 230v should disappear.
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