Help, I can't programme my new digistat!

[Dit]

Hello!

One year ago I had plumbers install a new combi boiler (Worcester Greenstar 28i junoir), radiators with thermostatic valves, and chose a wireless digistat (WorcesterDT10RF Programmer).

All very nice BUT I haven't been able to make the house stabilise at a comfortable temperature! I believe its down to my inability to understand the digistat. The boiler would sometimes switch on when the room temperature was already above the trigger temperature, with the rads chucking out heat and cooking us! Other times the room temp would be below the trigger temp and the boiler staying silent. So I asked the plumber how to use it and he didn't know. I phoned the Worcester helpline, and the gentleman explained to me that its not highly sensitive to fluctuations in temperature, so I shouldn't set the trigger temps too close (it was set for 18deg at night and 21 during the day). So I set it for 15 and 22 respectively but the boiler still seemed to come on at random times.

What I currently have is the boiler set to off (off/timed/once/on), radiator temp 4 (0-6). the digistat has four phases, set to 0530hh 21deg, 0700hh 18deg, 1630hh 21deg, 2330hh 18deg. The timer icon is visible to the right. It is currently kept on the bookcase in the lounge, but its location doesn't seem to help my problem.

Is there anyone out there with this equipment, that can give me some clues? Maybe just some settings that I can copy?

Thanks in advance, Tim

 

[Slugbabydotcom]

Instructions are HERE

 

[Dit]

Thank you, however I already have these instructions. I find them ambiguous-why would I programme the timers on the boiler when I have a digistat? I am assuming that the digistat overrides anything that is set on the boiler.

Tim

 

[Myson700B]

I do not have the same equipment as you but do have a boiler with operating controls similar to your Receiver and a wired programmer with controls similar to your wireless Transmitter/programmer.

This is my understanding of how things work for you. I'm happy to be corrected.

Receiver

The receiver selection should normally be set at timed to control the times when the boiler may start and stop heating the water. During the on period if the water thermostat detects that the water in your boiler is below the required 55 deg temperature the boiler gas will be ignited and heat the water until it becomes 55 deg.

Transmitter

The transmitter controls when a signal is sent to the receiver. If the air temperature at the thermostat in the transmitter becomes lower for perhaps a few minutes than you have programmed into it for the time of day a signal to start the water pump is sent so that water is pumped through the boiler and your central heating pipes and radiators. When the return flow of water into you boiler becomes less than 55 deg the boiler gas will be ignited. Similarly when the air temperature at the transmitter thermostat becomes higher for a few minutes than you have programmed into it for the time of day the transmitter sends a signal to stop the water pump.

 

[ChrisR]

why would I programme the timers on the boiler when I have a digistat?

It should be wired such that the CH timer on the boiler is On 24 hours, so all the control for that is on the digistat, which then behaves like a timed thermostat.

So either it's wired wrongly, or you have a boiler fault.

there's an override on the receiver which will bring the ch on, but I believe it resets itself after a few minutes.

 

[bengasman]

Looks suspiciously like a Drayton wireless. I had a bunch of them last year that gave up. The first thing you need to check is that transmitter and receiver actually talk to each other. Follow the first steps in the manual describing the `bonding` or `rebonding`. It is the part that tells you to hold the display at minimum of 1 metre away from the wired part.
When you do this, it is crucial that you take out the batteries and put them back in the correct order.
If the set has never worked, shame on the installer but if it has worked, it is probably a duff unit.
Could be coincidence, but every place where I had a problem with these units had wireless broadband.
I replaced them in the end with Honeywell cm927 and have not had any problems since.