PIV units

[Andy1733]

Been in contact with viessmann and all their boilers are capable of running a weather compensation sensor. I've purchased one via Screwfix today and shall be fitting it Monday.
My flow rate has been down at 55 degC so Hopefully by the end of January I should have a comparison Vs December. I've downloaded the outside terms for December and will do the same for January to give a more comparable reading.

As Arnie once said. I'll be back.

 

[Andy1733]

One for you Sparky's. I've received the weather sensor but it's not very clear on which wires go to where.

The Open Therm connector is located under the boiler so is easy to access. in the instruction manual it states using 3 and 4 connectors.
On the sensor it has 2 connectors one with a triangle symbol and one with X1. I have Inc the installation image and the sensor image and I believe the triangle connection goes. Into connector 4 on the OT and the X1 goes to number 3 on the OT. is the right way around. Can someone confirm this please

 

[brightspark]

Opentherm is different to weather compensater. You need to connect to terminal 4 and 3

 

[brightspark]

The opentherm is good for the likes of a nest thermostat

 

[Andy1733]

Opentherm is different to weather compensater. You need to connect to terminal 4 and 3

Yes m8. I know this. The manual list the connector as ot- ot+ and I know the 3 and 4 connectors are the ones I need but which end does the other end go to? All that says is triangle and X1. Even the instructions don't mention which connection goes where

 

[Sharpend]

It doesn’t matter.

 

[Andy1733]

Been in contact with viessmann and all their boilers are capable of running a weather compensation sensor. I've purchased one via Screwfix today and shall be fitting it Monday.
My flow rate has been down at 55 degC so Hopefully by the end of January I should have a comparison Vs December. I've downloaded the outside terms for December and will do the same for January to give a more comparable reading.

As Arnie once said. I'll be back.

Ok a bit of a update.
I fitted the weather compensator to my boiler at the beginning of January
I have the readings from 8th December to 6th January,
compared with 7th January to today. To make it easier Ive used December and January for the figures..
Plus as a comparison I recorded the AVG temperature for both months.

December figures
Gas total usage 2349kwh
Highest daily usage 104.5kwh
Lowest daily usage 43.8
AVG temperature 6.3C
High 14C
Low -5C

January figures after compensator
Gas total usage 1911kwh
Highest daily usage 89.6kwh
Lowest daily usage 38.5
AVG temperature 5.8C
High 13
Low -3

The temperature in both Dec and Jan are very similar.
I only use the gas for heating and hot water.
I made a slight correction to the room temperature after the compensator was fitted and upped the temp by 1degC. Plus I set it to turn on at 5am not 5:30am as in december.

From this short experiment the weather compensator looks like it's saved about 18% though if I didn't up the temp and bring the heating on 1/2 hour earlier it would have been closer to 23%

 

[binky]

Quite a saving.

 

[MikeJhn]

Just did a rough calculation on my old Oil boiler and it looks as though I am spending somewhere in the region of £20.00 more/day, @Andy1733 could I ask what sort of house this boiler is installed in so I can do a comparison.

 

[Andy1733]

It's a 3 bed semi with a 5mtr conservatory which is open plan to the house.

 

[MikeJhn]

Ah ha thanks for that, would not be able to compare in that case.