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Ollietheharp
I have a related problem which I have been trying to resolve for the past 12 months.
Whenever I power up my system my hot water turns on and will not switch off.
I have had the problem since last autumn we turned the heating on for the first time and it wouldn’t work. We called a plumber and he replaced the pump which had corroded but the heating and hot water wouldn't then turn off. Our old pump was a standard Grundfos pump with no speed settings. The newer one is the UPS2 version.
I have called the plumber a number of times since and he has had a look but doesn't seem to know what the problem is. I have replaced the 3-port valve, the actuator, the hot water thermostat and the programmer so far (like for like) with no effect. I have also asked an electrician to look at it (when he fitted the programmer unit) with no solution. The last time the plumber came he fixed the heating coming on as there was a poor connection in the junction box. He told me to move the hot water thermostat a foot further up the tank because it was too low (which I did without result). He has also suggested that the hot water won’t turn off because I need a new tank for £1000. Frankly, I didn’t believe him at that point as this is an electrical problem and nothing to do with the tank.
I have subsequently checked all the wiring connections in the junction box and also those at the back of the controller, all seem ok.
The current situation is that whenever the system is powered up, the pump is pumping and the boiler kicks in to generate hot water. We can turn the central heating on and off using the control unit but the hot water is on whether the control unit is set to on off or any other setting. It means that we have to power off the system to turn off the hot water, which is a bit of a pain.
To try to resolve this I have followed the excellent instructions from doitmyself on the post
cylinder thermostat connections
I did the CH only test and the HW only test which worked exactly as instructed with no faults.
I then did the CH and HW Test (Ports A and B open) (see below)
Power OFF
Turn cylinder stat to lowest
Disconnect cylinder stat wire from permanent live (T1) and reconnect to original terminal (T6)
Disconnect white wire from temporary location and connect to permanent Live (T1)
Power ON
Valve should move to mid position
I got to this point and the boiler turns on and pump kicks in even when the hot water thermostat is at minimum.
Turn Cylinder stat to max
Boiler should light (check that pipes from ports A and B both get hot).
If boiler does not light cylinder stat is faulty
Power OFF
Reconnect white and grey to original terminals (T5 and T7)
Turn HW OFF and CH ON
Set CH stat high
Turn Power ON
Valve should move to Port A open, boiler light and Port A get hot.
Turn CH OFF, so boiler goes out.
Boiler should go out but valve stay in CH only position
If boiler does not go out, check voltage on orange wire.
If orange has 240v, the actuator is faulty
If orange has 50-150v, there is a problem with the boiler
I tested the voltage on the orange wire and it was 240v.
I tested the grey wire too and that was 60v. Is this correct?
Does anyone have any suggestions as to what to do to fix my problem?
Many thanks in advance,
Ollie
Whenever I power up my system my hot water turns on and will not switch off.
I have had the problem since last autumn we turned the heating on for the first time and it wouldn’t work. We called a plumber and he replaced the pump which had corroded but the heating and hot water wouldn't then turn off. Our old pump was a standard Grundfos pump with no speed settings. The newer one is the UPS2 version.
I have called the plumber a number of times since and he has had a look but doesn't seem to know what the problem is. I have replaced the 3-port valve, the actuator, the hot water thermostat and the programmer so far (like for like) with no effect. I have also asked an electrician to look at it (when he fitted the programmer unit) with no solution. The last time the plumber came he fixed the heating coming on as there was a poor connection in the junction box. He told me to move the hot water thermostat a foot further up the tank because it was too low (which I did without result). He has also suggested that the hot water won’t turn off because I need a new tank for £1000. Frankly, I didn’t believe him at that point as this is an electrical problem and nothing to do with the tank.
I have subsequently checked all the wiring connections in the junction box and also those at the back of the controller, all seem ok.
The current situation is that whenever the system is powered up, the pump is pumping and the boiler kicks in to generate hot water. We can turn the central heating on and off using the control unit but the hot water is on whether the control unit is set to on off or any other setting. It means that we have to power off the system to turn off the hot water, which is a bit of a pain.
To try to resolve this I have followed the excellent instructions from doitmyself on the post
cylinder thermostat connections
I did the CH only test and the HW only test which worked exactly as instructed with no faults.
I then did the CH and HW Test (Ports A and B open) (see below)
Power OFF
Turn cylinder stat to lowest
Disconnect cylinder stat wire from permanent live (T1) and reconnect to original terminal (T6)
Disconnect white wire from temporary location and connect to permanent Live (T1)
Power ON
Valve should move to mid position
I got to this point and the boiler turns on and pump kicks in even when the hot water thermostat is at minimum.
Turn Cylinder stat to max
Boiler should light (check that pipes from ports A and B both get hot).
If boiler does not light cylinder stat is faulty
Power OFF
Reconnect white and grey to original terminals (T5 and T7)
Turn HW OFF and CH ON
Set CH stat high
Turn Power ON
Valve should move to Port A open, boiler light and Port A get hot.
Turn CH OFF, so boiler goes out.
Boiler should go out but valve stay in CH only position
If boiler does not go out, check voltage on orange wire.
If orange has 240v, the actuator is faulty
If orange has 50-150v, there is a problem with the boiler
I tested the voltage on the orange wire and it was 240v.
I tested the grey wire too and that was 60v. Is this correct?
Does anyone have any suggestions as to what to do to fix my problem?
Many thanks in advance,
Ollie
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