Better way to control water UFH system?

[Munchincocopops]

Hi - I have a 12mx5m garden room with water based underfloor heating. It works well but I am always wondering if there is a better way to control this.

At a guess I think there is about 400m of pipe as 4 loops in this area.

 

My installation has a wall thermostat (no floor sensor) and I the normal mixer valve/manifold/pump arrangement and when stat calls for heat it opens a valve (water from boiler to underfloor manifold/mixer valve/pump) which in turn activates UFH pump and turns on boiler.

Obviously when stat reaches temperature everything turns off.

 

Now I'm wondering about 2 things:

1. Better control of boiler as a 32kW boiler running at 70 deg C will soon meet mixer valve requirement but the stat is still calling for heat until the room reaches temperature. So I wonder if I use a thermocouple/programmable thermostat to measure return water temperature on the UFH manifold and set this to 45 deg c (?) and if above this turn off the boiler.

 

2. To install a buffer tank, use thermocouples/programmers to turn on boiler if buffer tank temperature is below 45 deg C and turn off boiler when temperture is above 60 Deg C. Might have to play around with max temperature to achieve a workable value. 

 

There will be some plumbing to do between boiler/buffer tank/manifold and extra valves possibly and likely some wiring changes to suit.

 

There might be a better way than what I am thinking so any comments or advice is appreciated.

 

Edited 3 hours ago by Munchincocopops

[JohnMo]

What in the rest of the heating system, as I assume you are not using 32kW just to heat a garden room?

[ProDave]

Fundamental question:  Is this a boiler just for the garden room, or is the garden room close enough to the house to be fed from the boiler in the house?

 

WHY run the boiler at 70C,  First thing turn that down to 55 or lower.  You will probably have to run the heating longer but it will work out cheaper.

[Munchincocopops]

Its a system condensing boiler and heats the whole house which are radiators. 

Plumbed so all have their own thermostats and timers. Mostly we live in the garden room so usually house heating is off or turned down.

Bathroom radiators come on whenever boiler is on.

 

So 70 deg is for water heating. All showers use hot water tank water so no electric showers.

 

House is quite large and built late 80's hence 32kW.

 

There is a third option. UFH has its own boiler?

 

Thanks for the comments.

[marshian]

What make and model boiler - does it have the functionality to do DHWP (Domestic Hot Water Priority) if it does then you wouldn’t have to run the boiler at 70 deg all the time just to satisfy the HW tank recharge temp required 

 

you coud probably drop the boiler temp to 60 - 65 and still get a decent volume of HW at a slightly lower temp storage

 

[JohnMo]

1 hour ago, Munchincocopops said:

radiators. 

Plumbed so all have their own thermostats and timers.

Some simplification sounds the order of the day. A couple of radiators kicking a huge boiler into life for 5 mins isn't an efficient way to run a heating system.

 

Will wait for the additional information requested above.