Posted by: @jeff

@derek-m i was just wondering what your thoughts are about using weather compensation to modulate the water flow temperature of a mains gas boiler.

Turns out i can use a Tado controller to modulate the water flow of my Worcester Bosch boiler. I thought the boiler would be too old. 

Am just checking with Worcester Bosch if they still sell a controller themselves that does something similar. I just have a standard basic wired danfloss controller at the moment. 

I seem to remember reading you were modulating the temperature of your gas boiler but may be mistaken. 

 

 

Hi Jeff,

We actually have an old Baxi Bermuda back boiler, which is very much 'handamatic' without any fancy controls, and is normally set at the minimum output temperature. The way I control our heating system is by monitoring the temperature of one of the radiators, which is compared against a calculated required temperature. When the radiator temperature falls, the boiler and water pump are switched on and warm water is pumped around the system. When the temperature of the radiator increases above the calculated value the boiler and pump are switched off.

I understand that more modern boilers are capable of temperature modulation but have not delved into their capabilities.

Please post what you find out from Bosch as I feel certain others will be interested.

Ours is a condensing system boiler so we have a hot water tank.

worcester bosch greenstar 30cdi classic

Installed in 2016 so reasonably new but not intelligent setup. More recent installations have more intelligent controls from the start i hear.

Just a basic wired Danfloss controller and fixed Danfloss thermostat currently in the downstairs hall. 

If you want to check compatibility with Tado then email them technical-advice@uk.bosch.com. I supplied them with model and serial numbers to be certain. 

Tado confirmed our boiler is compatible with tado in a modulate way via a Junkers HT BUS interface in our boiler. Tado also have smart TRVs that integrate as well. 

Am just waiting to hear exactly what Tado kit they recommend to replace our Danfloss controller and how it should be connected as it should be self install in theory. Will post when i hear. 

Will post when i hear back from my query to Worcester Bosch via their website so i have something to compare against. I would hope one lf their smart controllers would be compatible. 

@jeff this will work if you have the appropriate wiring centre from Bosch, or the boiler has priority hit water.

Bosch though are something of a technoluddite company unfortunately though

So Worcester Bosch replied and for my specific boiler i would need to get someone to install their optional internal diverter valve kit if i want to then use worcester bosch smart controls. Probably not something i am interested in doing if it turns out the tado control can be installed for less and do something similar albeit not the same. 

Indeed I suspected that would be the answer.

it would be worth doing if it is straightforward ie cylinder next to boiler or both pipes serving  cylinder back to boiler.

by not doing that the Tado will work on the one-off relay but you are not optimising the boiler to be as efficient as it could be, birthed saving using the bus connection would only be in the order of 10-20% depending on how you use it

Posted by: @alec-morrow

Indeed I suspected that would be the answer.

 

it would be worth doing if it is straightforward ie cylinder next to boiler or both pipes serving  cylinder back to boiler.

 

by not doing that the Tado will work on the one-off relay but you are not optimising the boiler to be as efficient as it could be, birthed saving using the bus connection would only be in the order of 10-20% depending on how you use it

 

Not impossible as you say. 

The boiler, cold water header tank and the two Danfloss 2-Port values (one for water, one for heating) are in the loft, with the boiler in the airing cupboard below on the first floor. All the water pipes run down the side of the airing cupboard. 

Will go back to Tado again as they were sure they could modulate the water flow temperature although given what worcester are saying about their own controller i  wonder if they are mistaken. I know they have had some success with some boilers where even the manufacturers have struggled.