Replacing Danfoss 4033 with Hive wiring

[Mark Billyeald]

Hi,
I’m looking for some help. I have an old valiant boiler and hot water tank but the timer mechanism has stopped working on the control panel - not ideal in the middle of winter meaning I can only control both water and heating via the switches. I was looking to replace it with a Hive system but would like to know if this is feasible. I have taken a photo of the wiring into the Danfoss 4033 but it’s a bit more complicated than i’d predicted. I do have a thermostat in the house and a thermostat on the hot water tank but I’m not sure if they will run separately - when the heating is on the tank will not heat up but I have noticed that when the hot water tank is on (and full) the heating seems to come on but not at full power. Any help appreciated.

 

[stem]

Yes, you can install a Hive Dual Channel version in place of the Danfoss 4033

The Danfoss terminals are identified as:

The existing wires move from the Danfoss to the Hive terminals that have the same function:

So:

L, N & E are self explanatory
Danfoss HTG on (2) = Hive Heating on (4)
Danfoss DHW on (4) = Hive Hot Water on (3)
Danfoss DHW off (5) = Hive Hot Water off (1)

Discard the wire link between the Danfoss terminals 1 and 6, The Hive has this link made internally for you already.

The existing room thermostat should be decommissioned. it can't just be removed otherwise the heating wiring will remain open circuit and will not operate. This is done by:

Tracing the existing room thermostat cable back to its origin. I can't tell you where that will be as that depends on where the original installer thought best to wire it in. Often (but not always) it's a wiring centre near the motorised valve, but it could be connected to other places. Once you have found the other end and positively identified it, preferably by testing with a multimeter, then:

1) Note where the 'Live' and 'Switched Live' wires that go to the thermostat are connected
2) Disconnect and remove the cable. (make sure other wires in the same terminals are not disturbed)
3) Insert a wire link between the terminals that you have just removed the 'Live' and 'Switched Live' wires from so that they are electrically connected

I can't be more specific abut this as you haven't provided any information about your existing room thermostat, such as its make / model or the wires connected to it. So if you need more help with this bit, post back these details.

Alternatively (but not very professionally) you can leave the old room thermostat wired in as it is and just set it to its maximum setting. The system will work OK as long as no one moves it from this setting.

The hot water thermostat won't change, that needs to stay because Hive only provides on & off time control of the hot water.

The other operational problems you have, if you are sure that is the case, are unlikely to be rectified by replacing the programmer. Electrically speaking the programmer / Hive are basically just 'on & off switches', that's all they do.

It's possible that the 3-port valve shown in the top left of your 3rd photo is not closing off the heating port fully when it should be and allowing some water to flow to the radiators.

 

[Mark Billyeald]

Many many thanks, it seems doable based on your advice. I have included a picture of the thermostat below if that provides any more info. Rewriting the hive unit I think I can do - im less confident with the thermostat bit if I’m honest.

 

[stem]

I described the professional way, of doing it. If you prefer, as I said, you can leave the existing thermostat in place and set it to maximum, and as long as it remains on that setting it won't interfere with the Hive. There is always a possibility it could be in inadvertently moved though, whilst it won't harm the Hive it could stop it working properly.

Or as another option, you could leave it in place and put the live and switched live in the same terminal which would replicate what I described earlier except the link is at the thermostat end and not the other end. There should be a diagram inside the cover that shows which are the live wires. With this option it doesn't matter what setting it's left on.