Baxi Platinum Weather Compensation

[jayc89]

I have a Baxi Platinum 33kW boiler (running in system mode) powering the downstairs UFH, upstairs radiators and unvented cylinder.

 

Around November, I had to pump the boiler temp up from 60 to 70 to keep the upstairs warm enough for the wife and kids. The long term solution is better insulation and airtightness, I know and is certainly not lost on me, but that's by no means a quick fix. 

 

From what I can tell the tech within the Baxi Platinum range is pretty old and the off the shelf Baxi weather compensation kit is not supported (load compensation would have been ideal for my use case - i.e. when only UFH is on, requiring 40c flow).

 

Short of replacing the boiler, is there anything else I can do to more intelligently set the flow temp? 

[PeterW]

How many zones and how many thermostats and where are they..?

 

Usual issue is the UFH flow is controlling the boiler return so the boiler isn’t firing as often as it should and the single rad zone is not receiving full flow. 
 

 

[jayc89]

3x UFH zones downstairs, each with their own stat. 1x Rad Zone and the Hot Water upstairs. Something like this;

 

 

There's also a bypass valve after the first tee from the boiler towards the HW and Rad pumps.

[jayc89]

Does anyone have any ideas?

[JohnMo]

How about a smart thermostat, with stop/start optimization.  This will learn how long your house takes to respond and try to keep a level temperature level.  Something smart like a Salus WQ 610 has all these features.

 

This will not change the water temperature, but response will be smoother.

 

The other thing is to run the water cooler for longer, so instead of running 70 degrees for an hour or so, run at 50/60 or lower for quite a few hours.  Weather compensation runs the boiler 24/7 at lower temperatures, so in effect you are doing the same, with a smart thermostat helping out instead of outside air temperature.

 

Watch you gas consumption internal temperature etc, to see what works for you.