I should have asked the installer but he's now away on holiday :o(
Anyway, just had an Alpha boiler installed (CD32C) and wireless room stat/programmer/timer thingy. The boiler itself has a thermostat numbered
0-9, there's the room stat, and then all the rads except one have thermostatic valves. Which thermostat takes priority and what should the one on the boiler be set at?TIA,
Puzzled of Cleethorpes
Boiler thermostat sets the temp the water is heated to. Set to achieve about
80°C (prob about 7 on your scale). Room thermostat controls the room temp (of that room) the boiler cuts out at and as such should have been placed in a sensible room that is not heated another way. I set mine at 20°C but something you're comfortable with, the others TRV's on the rads take up the difference since different parts of the house will cool and heat up at different rates, so these will all be trial and error to achieve temps appropriate for the room, ie lounge hot and bedroom cool. So long as you understand the basis of the setup I have explained the rest is trial and error for your house. Have your rads been balanced, now is the time to do that:
None of them in absolute terms - because they are all doing different jobs.
The boiler stat is controlling the temperature of the water leaving the boiler - typically about 80 degC and, whenever the heating is running, turns the burner on and off to maintain that.
The room stat attempts to keep the house at the correct temperature (typically 21 degC) by turning the whole system (boiler plus pump) on and off as needed.
The TRVs on the radiators attempt to keep each room at the right temperature by turning individual radiators on and off. These only have any effect when the system is running so, to that extent, the room stat has priority over them. Systems should be designed so that the room containing the room stat (and no TRV on its radiator) heats up slightly more slowly than the other rooms so as to give the TRVs time to act before the whole lot starts cycling on the room stat.
Thanks Mike, a couple of interesting points there. We've had a whole new CH system fitted (not just a replacement boiler) so yes, he balanced the rads as part of the job. Because it was done in the summer and we've not needed the heating on before now, we've only just noticed a problem in that he mounted the room stat in the lounge, which is the hottest room in the house because of the TV, the fire, the computer and the three people who usually sit in it
The stat is wireless so can be easily moved to another room but I remember reading somewhere that there should always be one rad in the system that doesn't have a TRV and that the stat is usually in that room, which in our case, it is - the radiator in the lounge is the one that doesn't have a TRV. So can the room stat safely be mounted in another room?
John.
Actually regs say it must be in that room, but you can of course do what you like.
Yes but of course you can easily have the situation that the TRV and thermostat will conspire to keep the rest of the house at the temperature required by that room whilst the room itself is actually stone cold! And the room without stat or TRV will have no control at all other than the programmed timings.
You have two problems to solve if you move it (and by the sounds of it you ought to, because the other heat sources in the lounge could result in you have a nice warm lounge and a cold house).
1) you need to ensure the TRV in the room you place the stat is not going to stop the system working properly. This is usually straight forward if you can remove the TRV head (they have a locking ring that unscrews from the valve base) leaving the rad uncontrolled and at its maximum setting. 2) You need some form of control in the lounge. The "best" solution would be to install a TRV on this rad. However you may find that you can achieve enough comfort simply relying on the timer/boiler cycling and setting the rad flow rate manually. Perhaps allowing for adding top up heat to the room from the fire etc.HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.