Wednesday, 6 December 2017

SIEMENS RDJ10RF Wireless Thermostat

SIEMENS is a brand normally known for its durability / reliability. And with a lot of their other products that is the case. But when it comes to thermostats, a big majority of their offerings score surprisingly low with customers. The SIEMENS RDJ10RF is no exception. While not the worst RF thermostat in the world, it's certainly not going to be a contender on any "Top 10" review lists for the cheapest, most reliable, easy to use thermostats for 2018 any time soon. As stated, this also applies to their other models, such as the RDH10RF. However, they're not all bad!

Not everyone has issues with the SIEMENS RDJ10RF

First off, I should make clear, that there are people who bought this model and are extremely happy with it. Why shouldn't they be? They bought it, wired it up, and it has worked without fault and gives them a trouble free operation of whatever they wired it up to operate. Such as a Combi Boiler etc. And to be fair, along with its easy to read digital screen, it does have some good features.

Frost protection, Auto, Comfort, Override, Day / Night and energy saving mode. The programmable part of the RDJ10RF runs on a temperature change style system, where the user sets the desired temperature when the thermostat comes on, and another, lower temperature for off. As in, night and day. The SIEMENS RDJ10RF is capable of performing several (2 on - off cycles) On / Off temperature changes in a 24 hour time line.


So, for example, you set the thermostat to come on at 5:30 am and go off at 8:30 am. It then stays off (on a lower temp) from 8:30 until you get back from work at 5:30 pm. It then comes on again at 5:30 pm until 11:30pm, and then goes off until 5:30 am. Then, unless you change it, it will repeat itself, coming on at 5:30 am again, going off at 8:30 am, etc. If you set the "Off" temperature too low the frost protection will kick in.


The main issue that seems to be affecting users is the RF signal strength. For most people it falls far below expectations with a very poor range of coverage. Some users claim that anything beyond 1 or 2 meters in distance and it struggles to connect properly.

RDJ10RF Intermittent Relay

Problems with the Relay becoming faulty are also an issue. Example: The relevant light on the receiver has come on, but the boiler has not fired up. This is most probably a faulty Relay. The short term remedy that has worked for some people, is by giving the receiver a bit of a knock or bang, most of the time this springs it into life. However, if you want some level of automation, with a unit known to have this issue, this faulty relay can not be depended upon. So, if you are at home and able to give the unit a kick start to get it work, then its not a problem.

But for automation, this fault makes it very hard to depend on. It's a terrible problem for such a unit. A few temperature inaccuracy's reported, and also some issues with the compatibility of rechargeable batteries. And batteries that have 3 quarters of their energy left performing badly, making the wireless communicating distance even worse. Having to constantly buy new battery's can be costly.

Overall, it seems as if the "wireless" aspects of this unit are somewhat lacking. Which really does massively decrease the convenience of having a wireless thermostat in the first place. Quite disappointing from a German brand like SIEMENS.

If you have this unit, or are thinking of buying one, it's definitely recommended to seek out the manual as some people find it a little different and somewhat confusing to set up. You can download the manual / instructions (Including how to use it) for the RDJ10RF here.