T
TonyK81
Hi all,
Well, here's my situation. We moved into a new place just a while ago, and we can't make the CH + HW system work correctly. Since we're new in the place, I can't tell if it was working properly before or not (oh, we had to replace the SCR at the very beginning). Here are the facts:
Compartments:
- Honeywell ST400C main controller
- Digistat SCR + RF3 wireless thermostat controller
- Honeywell V4073 3-way valve
- L641A Cylinder Stat
- Worcester Greenstar 12Ri boiler
- Grundfos pump
So, what happens at the moment is that the CH does not turn off. Assume everything starts from scratch. We just switch the power on, and all the controllers have HW + CH to OFF. Switch the ST400C CH to continuous, while Digistat thermostat is lower than room temperature. A red light turns on on the ST400C controller, but nothing happens. That's ok. We set the room thermostat higher than the current temperature, signal is sent and accepted, CH turns on (v4073 does it's thing, boiler fires up and the pump starts pushing the water). So far so good.
But once we turn the temperature down, the SRC gets the signal (and green light goes off), but the boiler and the pump keep going, and going, and going... I understand that they are not supposed to stop immediately, but they don't stop at all either! Interesting enough, the valve is still in the "CH on" position.
Troubleshooting:
While playing around, and after a gas engineer had a look at it, we figured out that once the CH has been turned off by the thermostat (but practically still going), if we turn on the HW, wait for a while, and then turn HW off, the valve responds to both and finally stops the CH (along with the HW of course).
It was suggested that the valve was malfunctioning, something about the microswitches. I replaced the valve motorized controller myself (I left the previous pipes), replaced the 5 wires exactly where the previous ones were. But annoyingy enough, same problem exists!
In the valve documentation there was the Y plan. I also searched the boiler plan, which made the whole wiring schema a bit different than what the Y plan suggested, since the pump is directly connected to the boiler, and both receive a "Live" signal from the valve Orange wire, or the Cylinder stat.
As far as I can tell, all connections look OK (though I admit they are a bit complicated). Only things I can't confirm is some wires coming from the Cylinder Stat or the ST400C, which in the Y plan are mentioned with numbers, while all i can see is the cable colours. But by following what should be connected with what, I don't see something wrong.. (also assuming it was "kinda" working for the previous owners, I assume it can't be all that wrong!)
Now, I also read that the Orange wire is supposed to have 240V or 100V everytime there is demand for CH only or CH+HW, respectively. I don't have a multimeter, unfortunately.
My question is, what could be that wrong that if HW is off, and CH is switched off, how come the Orange wire still sends a Live signal in the pump and boiler? Since both motorized valves behaved the same, I'm inclinced to believe there is a problem with the wiring. But can't see something wrong with it, at least not as much as I can tell. I'm not a professional, I have to point this out.
Any help, suggestions or even intuitions, are well appreciated.
Sorry for the long message! I hope my description was not too confusing. Feel free to ask for clarifications if needed.
Thanks
Well, here's my situation. We moved into a new place just a while ago, and we can't make the CH + HW system work correctly. Since we're new in the place, I can't tell if it was working properly before or not (oh, we had to replace the SCR at the very beginning). Here are the facts:
Compartments:
- Honeywell ST400C main controller
- Digistat SCR + RF3 wireless thermostat controller
- Honeywell V4073 3-way valve
- L641A Cylinder Stat
- Worcester Greenstar 12Ri boiler
- Grundfos pump
So, what happens at the moment is that the CH does not turn off. Assume everything starts from scratch. We just switch the power on, and all the controllers have HW + CH to OFF. Switch the ST400C CH to continuous, while Digistat thermostat is lower than room temperature. A red light turns on on the ST400C controller, but nothing happens. That's ok. We set the room thermostat higher than the current temperature, signal is sent and accepted, CH turns on (v4073 does it's thing, boiler fires up and the pump starts pushing the water). So far so good.
But once we turn the temperature down, the SRC gets the signal (and green light goes off), but the boiler and the pump keep going, and going, and going... I understand that they are not supposed to stop immediately, but they don't stop at all either! Interesting enough, the valve is still in the "CH on" position.
Troubleshooting:
While playing around, and after a gas engineer had a look at it, we figured out that once the CH has been turned off by the thermostat (but practically still going), if we turn on the HW, wait for a while, and then turn HW off, the valve responds to both and finally stops the CH (along with the HW of course).
It was suggested that the valve was malfunctioning, something about the microswitches. I replaced the valve motorized controller myself (I left the previous pipes), replaced the 5 wires exactly where the previous ones were. But annoyingy enough, same problem exists!
In the valve documentation there was the Y plan. I also searched the boiler plan, which made the whole wiring schema a bit different than what the Y plan suggested, since the pump is directly connected to the boiler, and both receive a "Live" signal from the valve Orange wire, or the Cylinder stat.
As far as I can tell, all connections look OK (though I admit they are a bit complicated). Only things I can't confirm is some wires coming from the Cylinder Stat or the ST400C, which in the Y plan are mentioned with numbers, while all i can see is the cable colours. But by following what should be connected with what, I don't see something wrong.. (also assuming it was "kinda" working for the previous owners, I assume it can't be all that wrong!)
Now, I also read that the Orange wire is supposed to have 240V or 100V everytime there is demand for CH only or CH+HW, respectively. I don't have a multimeter, unfortunately.
My question is, what could be that wrong that if HW is off, and CH is switched off, how come the Orange wire still sends a Live signal in the pump and boiler? Since both motorized valves behaved the same, I'm inclinced to believe there is a problem with the wiring. But can't see something wrong with it, at least not as much as I can tell. I'm not a professional, I have to point this out.
Any help, suggestions or even intuitions, are well appreciated.
Sorry for the long message! I hope my description was not too confusing. Feel free to ask for clarifications if needed.
Thanks
