CH Control

[Archie]

Since we had CWI (poly bead) installed, SWMBO thinks the house is colder. She may have a point. The system has a Drayton Digistat 1 in the hall controlling the boiler and TRVs on the radiators. The stat is mounted on the external gable wall and I think that since the CWI was installed, the off time of the stat is increased due to lower heat loss through the wall which caused the living room to cool down more it did before. The living room has a large 3.1x2m DG window at one end and a 1.6x2m DG patio door at the other end. The curtains are closed at night. The stat is set to 20C and seems to switch on at 19.5 and off at 20.5. I wonder the any other type of thermostat would give a narrower switching range or a more intelligent control. I had a look at some newer digistats and while they now display the temperature to one decimal point, there is no mention of and dead band. Any ideas on how to achieve a better temperature control without going OTT.

The house is a 3 bed semi-villa of brick/ breezeblock constuction and the boiler is W.B. 24CDI combi.

Archie

[John]

RF Thermostat and place it where you are spending your time?

[Archie]

How reliable are these devices? The reason I ask is that someone I know had a wireless burglar alarm and had to stop using it as is was so unreliable.

The boiler is out in the garage and since the device has a 2 year battery life, the TX power must be quite low.

Archie

[Dave Liquorice]

Ours (Danfoss TP75) is pretty good it does occasionally get out of sync but then the Tx is the otherside of 2' thick solid stone wall and 30 odd feet along the wall away from the Rx.

The Rx doesn't have to be at the boiler. Dependant on how your system is wired you might be able to put the Rx where the current mechanical stat is without having to make any wiring changes.

[cynic]

Surely the simple solution is to turn it up a degree or two. A one degree hysteresis sounds ok to me.

[John]

Might be worth lowering the temp of the boiler. Then the rads will stay on for longer and you will feel that warmth is being 'added'. If they are really hot they wil warm the room quickly and then shut down.

[Archie]

I did wonder about that. I tend to keep the boiler temp at max so that the house gets up to temperature quickly in the morning.

Archie

[Andrew Gabriel]

Boilers work most efficiently at the lowest setting at which they provide enough energy output. However, the heating system as a whole might not be most efficient at that point, for example if it means you have to turn the heating on many extra hours before it's required. Weighing up one against the other, particularly if you don't have the ability to change boiler temp automatically according to demand and it effectively has to stay on one setting, is always a compromise somewhere.

[Alan]

In message , Archie wrote

RF thermostats have a transmitter which you move to the room that use most and a receiver which you just mount in the position of the old thermostat to use the existing wiring.

[Davey]

Getting a programmable thermostat is the way forward. I have an RF Honeywell affair, and I put one in my folks place too. No bother and worth every penny.