Wiring hive to Drayton LP241

[steven mitchell]

Hi I have a drayton LP241 connected to a honeywell T40 stat.
It's a back boiler system with a hot water tank.

https://ibb.co/tJy8209
this is the wiring i have into the controller
https://ibb.co/jkNxp3T
and this is the wiring i have into the stat.
There is also a wiring centre box which has a ton of wires going to it.

I replaced the controller wiring up as a direct replacement for the hive as the terminals are the same. I disconnected the far right terminal on the stat
The hot water worked but the heating didn't.
You will notice there is a chock block on the controller,
This is live and goes to terminal 3 on the stat, ( 3rd from the left on the stat)
and the Pin 4 on the controller (far right) goes to terminal 1 on the stat (far right)
do i have to do anything with regards to the stat?
Any help gratefully accepted thank you

 

[stem]

The LP241 and Hive (dual channel version) have identical wiring so as you say it is a straight swap like for like.

However, you cannot just disconnect the old room thermostat. Otherwise the heating wiring will be left open circuit (as if the thermostat was above its set temperature) so the heating will not operate. As a temporary measure, if you put the wires back into the Honeywell thermostat as they originally were, and set it to its maximum setting and leave it there, the heating should now work with the Hive.

Ideally though it is really best to remove the old thermostat and wiring properly. This is done by tracing the thermostat wires, from the thermostat back to their origin and noting where they are connected. Then disconnect all of the thermostat wires. Now add a link between the terminals where you have just removed the Brown wire that went to thermostat 1, and the black wire with brown sleeve that went to thermostat 3 have just been removed from to complete the circuit.

It's a back boiler system with a hot water tank.

That's a bit of a brief description. If you have a fully pumped system with motorised valves all will be OK. However if you have an antiquated system with only pumped central heating and gravity circulation hot water. Then the Hive will need to be set to gravity mode.

 

[steven mitchell]

i would prefer to leave the stat in place if possible as it's a rental property so if i ever leave i'd like to leave it as i found it

 

[stem]

OK, I've edited my post above as something crossed my mind after I posted last time to include the following:

It's a back boiler system with a hot water tank.

That's a bit of a brief description. If you have a fully pumped system with motorised valves all will be OK. However if you have an antiquated system with only pumped central heating and gravity circulation hot water. Then the Hive will need to be set to gravity mode.

 

[steven mitchell]

yes it is gravity heating, theres a tank in the loft, and the water is mains fed

 

[steven mitchell]

how do i set the hive to gravity pls

 

[stem]

Erm. I don't think you understand, don't confuse gravity circulation with having a feed tank in the loft, that's completely different. You need to identify which system you have correctly.

how do i set the hive to gravity pls

It tells you in the instructions. But don't set it to that if it's not that type of system.

 

[steven mitchell]

mmmm ok, how do i do that? there is a pump for the heating under the hot water tank, it's a grundfos, it's a very old system as it's a rental property, and landlords don't like spending money on updating things

 

[steven mitchell]

there's writing on the wall near a shutoff valve which says ' cold water supply from tank in roof valve is crap' lol

 

[stem]

Old systems were plumbed so that the pump circulated water only around the radiators, but the hot water cylinder was not connected to the pump, it relied on the natural principle of hot water rising and cooler water falling to naturally circulate hot water around the hot water cylinder. This is known as gravity circulation.

A tell tale sign of a gravity system is that in order to have the heating on, the hot water also has to be on at the same time. Usually when selecting the heating to come 'on' at the programmer it automatically switches the hot water 'on' with it as well.

Gravity Hot Water, Pumped Central Heating

Fully Pumped

 

[steven mitchell]

yes if i switch the heating on and the water is off, it switches the water on automatically

 

[stem]

Sounds like gravity circulation of the hot water then. Here's the Hive instructions:

 

[steven mitchell]

i'll give it a go, thank you for your help

 

[steven mitchell]

you are a diamond, thank you so much, i have been playing with this for days,
and it all works or seems to the way it should, thank you again

 

[stem]

If you wanted to make it slightly more permanent, you could move the black wire from the Honeywell thermostat terminal 3 and put it in terminal 1 with the brown wire already there. That would make the connection permanent, so it wouldn't matter then if someone moved inadvertently moved the thermostat from its max setting. Just a thought.