replacing timeswitch for boiler

i have a Danfoss-randall 103 electromechanical t/s which controls the heating of the hot water in the house

It has recently gone faulty and now we have to manually switch on to get the boiler to switch on. (as the nights are getting colder this means that first one up in the house every morning rushes down stairs to turn the boler on (and at the same time central heating swiches on))

It obviously needs replacing and i have come across the model Danfoss Randall 103E7

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i correct in thinking this can be used as a replacement?

The advantage of the electronic version is that according to the manual at

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you can have different start times for different days of week (ie we could programme for slightly later at weekends when we get up later and slightly earlier on a monday when i get up at 5am to catch train)

Can anyone confirm that my assumptions are correct and that i can switch out a 103 and replace with a 103E7?

I have read that the same backplate etc is used so does this mean that "switching" is something a "competent" person can do. If not can anyone recommend someone in Whitefield area (between manchester and Bury). Should i be looking for an electrician or a central heating specialist?

Reply to
Virgin Newsgroups
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Even if it isn't a direct swop it's something any half competent electrician should be able to do in his sleep. ;-)

Reply to
Dave Plowman (News)

Yes it is a straight swap. Turn the power to the boiler off, remove the 103 from the backplate and replace it with the 103E7 and turn power back on.

Adam

Reply to
ARWadsworth

And some swaps are nightmares. Imagine if the old programmer has been tiled/plastered around then try getting it off the wall without damaging anything.

Adam

Reply to
ARWadsworth

As others have said, this is a direct replacement for your current timer.

*However*, it's only a single channel device - and doesn't provide independent timing for hot water and central heating.

How is your system configured? Is it capable of independent control of HW and CH? Are there any motorised valves? Does the pump run all the time the boiler is on, or only for the CH? Is there a room stat? If you answer these questions, we might be able to suggest ways of making the whole thing operate more efficiently - without costing the earth to implement.

Reply to
Roger Mills

The existing contoller heats the hot water and radiators at the same time. If we want to turn the radiators off then we need to turn the room thermostat in the hallway to off which means only the hot water is heated.

I believe the room thermostat is connected to a moroised valve which closes off the central heating when the room thermostat in hallway is turned down,

I assumed that replacing with the electronic version of the randal 103 would mean that life carries on the same (ie no independant control of the CH) from the timer. The only advantage that we wouild get with the electronic version would be 3 on/offs per day and could have different timings for each day of the week. Yes it would be nice to have independant control of CH and HW but i cannot believe this would be very cheap to implement on current system!!

Reply to
Virgin Newsgroups

In message , Virgin Newsgroups writes

Yes, same backplate IIRC

Reply to
geoff

Then something needs to change if you want better controls.

It should be possible to install a two channel programmer. The CH and HW may not be independant as you may have to have HW on when you call for CH but a single channel programmer to control both is a waste of money.

Adam

Reply to
ARWadsworth

What curently stops the hot water from getting too hot - is there a thermostat on the cylinder? If so, what does it control? Does the pump run when *just* the hot water is on, without central heating?

Chances are that you are wasting a lot of gas keeping the boiler hot when it doesn't need to be hot - and that some updated controls would pay for themselves in a relatively short period. Depending on what you've actually got - and you haven't really told us yet - you could probably transform your system for less than a couple of hundred quid in valves, stats, etc. Of course, if you have to pay someone to fit them, the cost will be higher - but this *is* a DIY group!

Reply to
Roger Mills

Danfoss make the TP9000 which is a two channel programmable thermostat.

One channel switches the hot water off and on preferably inconjuction with hot water thermostat.

The other channel controls the central heating using a remote temperature sensor. The sensor would replace an existing room thermostat.

Reply to
Michael Chare

My system sounds exactly like yours - the timeswitch merely controls the boiler on/off, while the roomstat in the hall controls the pump and hence the CH. If we want HW only we just turn the roomstat down. Incidentally we don't have a motorised valve, the roomstat just switches off the pump and the HW is gravity fed.

I have recently faced the same dilemma. Should I just change the existing Danfoss 103 mechanical switch to an electronic version (Danfoss 103E5) or update the whole system to control HW and CH separately. I have just fitted new kitchen cupboards and re-tiled the kitchen so I decided against updating the system as it would have probably involved new wiring and disturbing the new tiles, so I just fitted the Danfoss 103E5 instead of the old 103.

It's a doddle - assuming someone hasn't been lazy and tiled round the old switch and grouted it in, as it needs to slide upwards to remove it from the backplate. Then just fit the new switch in it's place on the old backplate. The connections are all plugged in when you slide the new switch in place so no messing about with disconnecting and re- connecting wires etc.

Lots of significant price variations on the new switch on t'internet by the way - I just used the cheapest and it was delivered in 48hrs.

Pete

Reply to
petek

Are you sure there is a motorised valve? It's just that with fully pumped systems it's usual to provide independant control. Only means a few feet of extra wire. Older systems often relied on gravity circulation to heat the water.

It's only a bit of rewiring if you do have a fully pumped system. If you have an electrical thermostat on the storage cylinder it likely will be fully pumped.

Reply to
Dave Plowman (News)

And even if it's gravity HW and pumped CH, it's not rocket science to convert it to a C-Plan system, using a motorised valve in the HW circuit and a tank stat on the cylinder. That way, you get:

  • the ability to have HW and CH on at different times
  • the ability to run the radiators hotter (by turning up the boiler stat) without the risk of the HW getting too hot
  • boiler interlock - so that the boiler is turned off when both HW and CH demands are met, rather than wasting energy by cycling on its own stat

Well worth doing, in my book!

Reply to
Roger Mills

I do come along quite a few fully pumped but badly controlled systems at work.

Basically the programmer operates the same way as a gravity system ie HW must be on when CH is on. The HW output of the programmer fires the pump and the CH output controls a 2 port valve to allow water around the radiators.

A real bodge job when you consider how little to would take to turn it into an S plan

Adam

Reply to
ARWadsworth

This discussion is old by now but my Danfoss 103 seems to be an old version with a curved top rather than the rectangular shaped 103E7. Are the wall plates the same?(i.e can I buy a 103E7 now and expect it to fit my old wall plate?)

When going on holiday it would be great to be able program thw Danfoss to switch the whole sytem off but have it come on again say 2 days before my return. I think this is possible with the E7 but is it possible with the E5?

Reply to
bruckshaw1

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