Saturday, September 05, 2015

Be your own central heating engineer

Getting cooler isn't it. Nice to know that your Bosch Worcester Greenstar 30CDi gas-fired condensing boiler is working OK.

Last night the central heating failed. That is, the remote controller we have in our living room was registering 19.5 C and showing its little arrow to tell the central heating to turn on - but the pipes remained cold.

Suffering my usual aversion to physical reality and obtuse/opaque systems, I reluctantly went upstairs to the airing cupboard and examined the Siemens RCR10/433 wireless 'base station'. All the lights were out. I prodded the 'Set' button ('Do Not Touch This Button') and then, when nothing much happened, pressed the even scarier 'Reset' button. Then I turned all the power off at the socket and turned it back on again.

Yep, nothing.

This morning I changed the batteries on the Siemens RDJ10RF remote unit while Clare suggested we move blankets away from the boiler and hot water tank to 'prevent overheating'.

As magical thinking failed us, I recalled Adrian's advice of the previous evening and googled 'How can I reset Siemens RCR10/433'. And here was the advice.
If the Siemens thermostat remote unit (RDJ10RF) loses connection to the base station (RCR10/433) next to the boiler (possible symptom: the base station green light goes out).

---

1. Make sure the thermostat remote unit has its vertical switch set to 'run' and the horizontal switch set to 'auto'.

2. Loosen the screw holding the thermostat backing plate (situated underneath, just loosen the screw don't take it all the way out). Take the unit to the boiler.

3. On the wall unit/receiving unit next to your boiler there are two buttons 'Set' and 'Reset'. press and hold the reset button for 4 secs until orange light starts to flash.

4. Then press the 'Set' button on the same unit (the light should flash again).

5. Press the 'Learn button on the back of the thermostat unit - try to be a good meter away from the wall unit /boiler. The lights should flash and then turn green.

6. Press the 'test' button on the back of the thermostat. This sends a test signal to the boiler . The green light should come on again. When this has happened press the test button again to switch off the test signal.

This should now work.

And miraculously, it did. There was, however, more information on the Internet from those people for whom this procedure had not worked.
"I too have a malfunctioning RCR10/433 which responds to a sharp tap. I've done a bit of investigation but not fixed it yet, thought I'd share what I've found so far.

There's a click when the orange light comes on, but the relay contacts don't switch over until given a tap (checked with a multimeter).

There are two obvious possibilities here - duff relay or failing power supply capacitor. The click from the relay suggests the former, but I need to check the voltage applied across the coil to confirm ... ."
I went upstairs armed with a hammer, but was saved by Clare's ecstatic call of "You're a genius!"

The rewards of being in trade, even as a complete amateur.

---

Update September 14th 2015. The central heating has failed to come again today. I did 'all the above' but this time it failed to have any effect. I even tried (gently!) tapping the base station upstairs with the hammer. I can only assume that there is a fault in the room-remote or boiler-end control unit. We are in process of calling in an engineer to take a look ...

... and five minutes later, after calling an engineer, I go upstairs and tap the wretched base station with the hammer again (perhaps a little harder). And mirabile dictu, the heating turns on ...

Update September 23rd 2015. A qualified central heating engineer has now visited and checked everything. He informs me that the controllers are fine; the problem lies with the (rather old) three-way valve which routes hot water between the boiler and the hot water tank and/or the central heating system. Apparently it's sticking and not always responding - he will order a replacement.

 I am put in my place (along with the Internet).

Update October 14th 2015. The engineer has been busy and has not yet come. In his absence the system has continued working rather erratically. I checked the installation guide for the three-way valve (The Honeywell V4073A) - it states that the operating temperature must be less than 52 deg C. I wondered if it was overheating so I cleared clutter around it and left the airing cupboard doors open. Since then, cross your fingers, the central heating has been working OK.

Update October 22nd 2015. The system continues to behave erratically. The Honeywell V4073A three-way valve has hot water in all three of its attached pipes when the CH is set to 'on'. This indicates the valve itself is working; it's just that hot water is not being pumped around the house. The engineer is tied up with a house-construction contract and is not available until the beginning of November - but he has given me the number of his former boss to try in case we need action sooner. I'm on the case.

Update November 4th 2015. The central heating engineer, Ian Hosegood, came today. It turns out the problem was indeed with the Siemens wireless base station (wall-mounted next to the boiler). It was showing the radio link to the living room thermostat as active, but the relay to the boiler/pump had not tripped. This is the bug in the device highlighted above. Ian switched it out for the Honeywell CM927 wireless programmable room thermostat and upstairs relay box.

Finally, the central heating is working again.

---

17 comments:

  1. I just wanted to say thank you so much for this post. We used the hammer on our base station and, as you say, mirabile dictu, the heating came on. So problem not actually solved but (a) you have shortcutted it for us and (b) as a temporary solution the hammer, touch wood, really works.

    ReplyDelete
  2. the whole sequence thing worked for me - saved the day. thank you

    ReplyDelete
  3. Very useful post, was actually looking for the voltages I should find but using the severe tap method showed me it should be 240ish. Thanks very much. Time for something different.

    ReplyDelete
  4. This. saved me a pounds worth of boiler replacement. Though sounds like you had it rougher. How's the honeywell thermostat working out for you?

    ReplyDelete
  5. Thank you. Thank you. Thank you.

    ReplyDelete
  6. I couldn't believe this! I changed the valve actuator this morning thinking that was the problem. I have spent several hours then following the instructions as to how to reset the wireless link without results. I then googled and found this post. 10 minutes ago I gave the receiver several taps with a hammer and hey presto!!

    ReplyDelete
  7. Fixed for me also!

    ReplyDelete
  8. I finally realised that there are two versions of the Siemens RCR10/433 receiver.

    The difference relates to the two buttons. The one shown at the top of this item requires two buttons (OVERRIDE and LEARN) to be pressed together to RESET the unit but mine is different.

    Mine has a SET button and a RESET button - the latter is recessed to avoid accidental presses.

    This is the way I restored communication and operation of the heating on my system -

    Before starting, turn off the power to the receiver for at least 5 minutes, and then turn it back on. Remove the stand/wall plate from the back of the transmitter/thermostat to expose the TEST and RESET buttons.

    1. Press and release the SET button on the receiver. This puts the receiver into learn mode.

    2. Press and release the LEARN button on the back of the transmitter/thermostat.

    3. A good signal connection is indicated by a green flashing LED on the receiver.

    4. To test the receiver/boiler operation, press the TEST button on the transmitter/thermostat. This will switch the relay on in the receiver, irrespective of house temperature, and turn the radiator pump in the boiler on. (The RF TEST symbol appears briefly on the transmitter/thermostat display but ONLY when you press the TEST button - it does not stay on.)

    5. An orange LED on the receiver indicates that the relay is on. Within a short time the pump and boiler should start and begin heating the radiators.

    6. Once you have warm radiators, press TEST on the transmitter/thermostat again to stop the test and return to normal time/temperature control. Replace the stand/wall plate on the back of the transmitter/thermostat.

    7. Check the time and temperature settings on your transmitter/thermostat and adjust if required.

    ReplyDelete
    Replies
    1. Thank you so much...i searched all day for a solution for this version

      Delete
  9. is there any recalls on the Siemens remote control for a gas boiler my
    is not connecting to the boiler anymore after a 4 years old

    ReplyDelete
  10. Thank you very much, the instructions worked perfectly. I have just moved in to a new property and the rx/ tx units weren't communicating when I attempted to turn on the CH. It didn't help that the instructions for the receiver didn't match the unit. Also thanks to Tim R for pointing out the orange light indicating comms working.

    ReplyDelete
  11. Do not know much about this system as new home for us. However, I have set the temperatures and on/off for day and night but I cannot understand why the heating is not coming ON or going OFF correctly yet another night whereby the house was baking hot in the middle of the night when temp is set at 18.5 and when I come in, in the day and temp reading below our daytime required set and heating not come. I am having to physically turn the heating remote on/off manually. What can be done to remedy this as I am concerned about my heating bills

    ReplyDelete
    Replies
    1. Hard to know. Check that the time is correctly set in the controller. For example, it's easy to confuse am and pm.

      Delete
  12. Hahaha like the hammer, I found banging the remote firmly against the wall worked! Followed the rest of the instructions and all is good!

    ReplyDelete
  13. Can't belive it, a little percussive maintenance clicked the heating on.
    Can't be doing that every time we need some heat though, so I think a replacement may be in order soon.

    ReplyDelete

Comments are moderated. Keep it polite and no gratuitous links to your business website - we're not a billboard here.