Smart Relay Switch in Place of Old LP522 Programmer

[AlasdairG]

So I'm looking to move on from a old lifestyle LP522 programmer for our boiler and have this replaced with a smart relay switch, to control the boiler on and off via Home Assistant. (Recently just move in)

There is also a dial thermostat in the hall that switches on and of the CH, which I think we will deactivate.

I'm just trying to work out currently what wires I will need to hook up where to the smart relay switch.

Currently iv got 2 red wires going to L and to 2 black going into N. Blue wire going to 1, a different red into 3 and a yellow into 4.

The boiler is a combi and the HW tank has since been removed.

Iv attached the wiring iv got and the wire diagram on the back of the current programmer. Iv also attached the new smart relay switch and it's inputs. The new relay switch can run in dry contact mode which should be able to control the boiler.

Any assistance would be greatly appreciated.

 

[ericmark]

It would seem wired for a Y Plan, and that when combi fitted, there has been some corner cutting, as will no longer be Y Plan, so what we look at is how can we gain more control without working out what has gone on in the past.

The backplate is universal, be it Hive, Wiser etc, they all use the same backplate. But you want a single channel, but wired for a two channel, so either work out the wiring, or fit a two channel.

So let me guess what you want.
1) Some frost protection, so what ever replaces the lifestyle LP522 programmer need that built in.
2) Connection to either Alexa or Google home, so you can use voice commands.
3) Geo-fencing.
4) Override geo-fencing when required.
5) Multi temperatures depending on time of day.
6) Connection to TRV heads, so you have multi-zone.

The list goes on, and to be frank an on/off device will not really do enough, and you will need at some point to increase your control, so the best option is to select something designed to do all.

However, even if simple on/off is all that is required, you still need to work out what you already have. Has the three port valve been removed, and do you have some wiring centre to wire it all into?

 

[AlasdairG]

It would seem wired for a Y Plan, and that when combi fitted, there has been some corner cutting, as will no longer be Y Plan, so what we look at is how can we gain more control without working out what has gone on in the past.

The backplate is universal, be it Hive, Wiser etc, they all use the same backplate. But you want a single channel, but wired for a two channel, so either work out the wiring, or fit a two channel.

So let me guess what you want.
1) Some frost protection, so what ever replaces the lifestyle LP522 programmer need that built in.
2) Connection to either Alexa or Google home, so you can use voice commands.
3) Geo-fencing.
4) Override geo-fencing when required.
5) Multi temperatures depending on time of day.
6) Connection to TRV heads, so you have multi-zone.

The list goes on, and to be frank an on/off device will not really do enough, and you will need at some point to increase your control, so the best option is to select something designed to do all.

However, even if simple on/off is all that is required, you still need to work out what you already have. Has the three port valve been removed, and do you have some wiring centre to wire it all into?

So the smart relay just needs a on off for what iv got. I have smart TRV's that will be able to call the relay switched to turn on and off when. Basically call for its own heat per radiator/ room as they will be grouped.

Iv got automations set up to on the TRV's with PIR and mm wave radar motion sensor to turn on the rads when someone enters the room, and to turn off when they leave and go into a base temp schedule. Anti freeze is also all set up. Geo fencing is also already set up.

This is all working and will turn on the radiators. The last bit is just to now have the smart TVR's call to a smart relay to turn the boiler on or off. Right now this only works if I manually turn on the CH.

I've got some radiators without smart TRV's so to keep flow in the system at all times that are open.

Just need to make sure I get the wiring right on the smart relay. Yes the 3 port value has been removed by the looks of things.

 

[ericmark]

I find it takes nearly an hour to re-heat a room. Eco setting 17°C and comfort setting 21°C, so geo-fencing does not work, it takes too long to re-heat the house.

The basic idea is, with a modulating boiler, as the TRV closes, the by-pass valve opens, allowing hot water to return to the boiler which will turn the boiler down or off.

The problem is the boiler will cycle on/off, as nothing tells it to completely turn off. The Linked TRV head is designed to get around this problem, but many homes have the radiator on an outside wall, so the TRV gets colder than the room, so it needs a thermostat on an inside wall to control the TRV.

But why reinvent the wheel, we have systems like Drayton Wiser already designed to run central heating as required, why try to build one's own system?

 

[CountryFan]

I would say it’s a case of working out if both wires to L and N are required, if they are then keep the same, if not transfer the ones that are. Number 4 would go to L out and L in would need a link to L. Number 4 is also the Live to the room stat and the room stat switch live to the boiler so you need to figure that out.

 

[AlasdairG]

Ok so I think I know what I'm gonna do. I'm gonna go to the room thermostat and wire in the switch there to act as a smart thermostat in which the TRV's can call for heat.

This will mean the old LP522 will stay in place and just have the boiler on ready for a call for heat from the "thermostat" (now a smart relay switch) this way again it can self modulation as it currently does already.

As it stands the LP522 does nothing when the HW is active as well there is no longer a hot water tank so the boilers needs to be on at all times to get hot water.

 

[ericmark]

I think I can see your idea? But not how it will work.

So in each room, we need a device, not on an outside wall, to detect when it needs heat, both time and temperature. This will cause the TRV to open and the boiler and pump to be triggered.

There also needs to be a by-pass valve for when the TRV is not open enough, for hot water to return to the boiler to turn its output down.

We also need a method to turn the whole system off when the home is not occupied, and on, likely in sequence, when the home is about to be occupied again. This is called geo-fencing, and my attempts to use it have failed to turn the home back on in time. It turns off OK, it is the turning back on bit that fails.

I looked at the whole idea of SCADA (Supervisory Control and Data Acquisition) and a PLC (Programmable logic control) but the problem is, if it fails, who other than me can repair it, at 74 I have to accept I may not be able at some time not be able to repair it myself, so felt it more prudent to use domestic equipment, designed for the job.

 

[AlasdairG]

I think I can see your idea? But not how it will work.

So in each room, we need a device, not on an outside wall, to detect when it needs heat, both time and temperature. This will cause the TRV to open and the boiler and pump to be triggered.

There also needs to be a by-pass valve for when the TRV is not open enough, for hot water to return to the boiler to turn its output down.

We also need a method to turn the whole system off when the home is not occupied, and on, likely in sequence, when the home is about to be occupied again. This is called geo-fencing, and my attempts to use it have failed to turn the home back on in time. It turns off OK, it is the turning back on bit that fails.

I looked at the whole idea of SCADA (Supervisory Control and Data Acquisition) and a PLC (Programmable logic control) but the problem is, if it fails, who other than me can repair it, at 74 I have to accept I may not be able at some time not be able to repair it myself, so felt it more prudent to use domestic equipment, designed for the job.

So the Smart TVR's I have have their own temp sensor, but as correctly pointed out these can be off. They each off offsets that can be set to correct the temp, however each Smart TRV can also be connect to an independent temp sensor else where in the room.

Example my living room has 2 rads with two smart TRV's. They are both grouped together and thus turn on and off together when the temp is to low or high. These two TRV's are getting temp data from a temp sensor that is sat about 1.5m above the group on a inner wall shelf.

Currently when this senior reads below a desired temp it tells the rads to open. And when it's too high tells them to close. From here the the TRV's need to tell the boiler to fire for heating, which I can do with an automation from the smart relay assuming ai connect this in place of the old room stat.

This is how all the rooms are set up beside the hallway and bathrooms, which always have their rads open to allow some flow in the system.

When someone is not detected the heating in that room turns down to 17c, When someone is it turns up to 21C. This can take a little bit, so iv got automations to start a pre heat based on our typical schedule as a baseline. Should no one be detected after 30 mins it will switch that room back to 17C.

It's actually a very complex set of automations with lots of IF and AND condition's that's working so far really good.

Just need to allow everything to call for heat on its own now. So yea I think replacement the current room stat with the smart relay is the way to go here.

 

[ericmark]

I wish I had enough go about me to do the same as you. I have thought about it, my boiler is on/off only, and I think there are some hidden parts, where the double garage was turned into a flat. So it works well enough for me, so given up adding more controls.

Late mother's house had a modulating boiler, and mid-winter the TRV's worked well, each radiator would get hot in the morning, when reheating the rooms, but would then settle to being just warm and maintain the room temperature, with all analogue control, but Autumn and Spring there was a problem turning whole boiler off and on when required.

I considered all sorts of ideas to turn the boiler on/off as required, but mother died before I had sorted anything, and the house was sold, and both my old house and this house do/did not have modulating boilers, so don't really need analogue control.

The Drayton Wiser is not prefect with an on/off boiler, but it is near enough.

As to turning heating on/off with occupation, either the room or whole house, the problem is recovery time. My living room radiator in this house is around 1.5 kW x 2 so 3 kW in all and the room is large, so looking at an hour to reheat. Last house living room had a 2 kW standard radiator, a 3 kW fan assisted radiator and a 4.5 kW gas fire. So we could come home on a cold day with heating off, and within 20 minutes the room was warm.

I am a big fan (excuse the pun) of the fan assisted radiator, but it was designed to be used with non modulating boilers, and with parallel plumbing they can cause the boiler to modulate too early.

I look at where I volunteer where they use a one pipe heating from the boiler, it works very well, giving a great ambiance, with steam coming from the final carriage, whereas with other heritage railways, they use diesel heaters, which need batteries charging to run them, but still work when diesel hauled, where ours clearly only work when steam hauled, it needs a real boiler, not just a water heater.