Installing and Question about Salus RT500RF

[Toshe]

A bit of intro to my situation:

I want to replace my current (old) analogue thermostat with something better and more precise. At the moment if temp. is set to 22 degrees room can get as hot as 28 or more before it shuts off. I usually dial it down to 15 for it to shut off - and then it won't turn back on until it gets very cold. Needless to say it's hardwired near the boiler on a wall right of the exit door to my apartment. So I suspect the combination of it being up a colder wall + being out of the living room across in the hallway (even though there are no doors between) + the fact that these old things probably have a precision of at most 3 degrees (and I've read it can be as bad as 8 degrees) - is what makes it work terrible.

The actual questions:

Q1: How do I install the RT500RF considering this is how it's currently wired (3 wires installation):

Where (according to manual):
1 = Live [called phase here] (R)
2 = Boiler output [don't know what this is, i presume it's the vital wire, would love an explanation] (???)
3 = Neutral [called zero here] (N)

(in a youtube video for the RT500RF there was a mention of linking the Live and Common in the receiver, but it's not mentioned anywhere in the manual - so I am beyond confused up to this point)

Q2: If I turn the receiver of the RT500RF does it mean that my boiler will be constantly off (it's something I like doing with the current thermostat which has an off switch - turning it off when I go out).

Q3: By installing the wireless (main) on the wall behind my sofa and by using this digital thermostat - I should greatly improve the precision of the system and it should (in theory) go off if temperature goes just a degree over the set temperature, and on if it goes under it, correct?

Thank you so much if you take the time to help me out, I would be greatly indebted.

 

[muggles]

You want something more reliable and you've bought a Salus? Hmmm....

How is it wired currently? Can you post a picture of the actual wiring? What boiler so you have?

 

[Toshe]

The diagram I provided is how it's actually wired to my current unit that is apparently this model:

http://www.tehnoelektro.rs/slike_novo/termostat_2011.jpg

And considering where I live I have very few options of what is available for purchase in retailers, and ordering online is not an option due to high VAT and customs. I have not yet bought the Salus but it's the only thing they sell here - and I read very good amazon reviews for it (some from electricians/plumbers).

In any case you are free to suggest something better for the price range, I might try to buy it in my visit to Germany for the holidays. But in the mean time I want to know how to wire these units, particularly this one and most importantly if it's possible to be wired in my existing scenario with the described 3 wires.

EDIT: I have literally no idea what boiler I have, it came with the apartment, has a custom made by some local heating company (has a not perfectly symmetrical-y made casing for it out of sheet metal painted white with some controls bolted on it etc). I think they call it a mono-block radiator heater.

 

[muggles]

But in the mean time I want to know how to wire these units, particularly this one and most importantly if it's possible to be wired in my existing scenario with the described 3 wires.

You won't get much help with an attitude like that. I'm out

 

[Toshe]

You won't get much help with an attitude like that. I'm out

I certainly have no idea what you mean. I tried to be as concise and descriptive as I can. If my confusion and manner of explaining is insulting to you I am sorry indeed.

 

[stem]

The Salus RT500RF is designed to control both the temperature and the time, of a central heating system only. (e.g. a combi boiler that doesn't require hot water time control) It should be continually powered, so if your existing thermostat is powered via a timeswitch / programmer elsewhere, it's not really quite what you need.

Old mechanical thermostats are not always accurate, and get worse as they wear and age. If you do have time controls elsewhere, I would seriously consider just swapping the old thermostat for a new accurate digital wired one. The link you your existing thermostat even states it has a 1 to 2 degree accuracy. Appalling.

However, if you do decide to install the Salus, and bypass any existing central heating time control, then for a 230 VAC system, the Salus should be wired as follows:

1) Live will be the incoming live supply (presently to terminal 1) This should be a permanent live, and not controlled by a timeswitch elsewhere.

2) Live should also be linked to the COM. This provides a live supply to the Salus internal contacts, which, when the device is 'on'...

3) ...will energise the NO terminal which is the switched live supply to the boiler (presently to terminal 2) to turn it on.

4) Neutral is self explanatory. (presently to terminal 3)

Regarding the link, the drawings provided by Salus are typical only, but if you look at the table at the bottom of page 6 in your manual, you will see that it says COM = Linked Live feed (230V AC heating applications only)

I am a bit concerned about your lack of basic electrical understanding, the table on page 6 of the Salus instructions, along with the details you have given above, provide you with all of the information you require.

 

[Toshe]

The Salus RT500RF is designed to control both the temperature and the time, of a central heating system only. (e.g. a combi boiler that doesn't require hot water time control) It should be continually powered, so if your existing thermostat is powered via a timeswitch / programmer elsewhere, it's not really quite what you need.

Old mechanical thermostats are not always accurate, and get worse as they wear and age. If you do have time controls elsewhere, I would seriously consider just swapping the old thermostat for a new accurate digital wired one.

However, if you do decide to install the Salus, and bypass any existing central heating time control, then for a 230 VAC system, the Salus should be wired as follows:

1) Live will be the incoming live supply (presently to terminal 1) This should be a permanent live, and not controlled by a timeswitch elsewhere.

2) Live should also be linked to the COM. This provides a live supply to the Salus internal contacts, which, when the device is 'on'...

3) ...will energise the NO terminal which is the switched live supply to the boiler (presently to terminal 2) to turn it on.

4) Neutral is self explanatory. (presently to terminal 3)

Regarding the link, the drawings provided by Salus are typical only, but if you look at the table at the bottom of page 6 in your manual, you will see that it says COM = Linked Live feed (230V AC heating applications only)

I am a bit concerned about your lack of basic electrical understanding, the table on page 6 of the Salus instructions, along with the details you have given above, provide you with all of the information you require.

Thank you so very much. Yes, I definitely lack understanding of circuits, this helps out a great great deal! Especially about the part about the old thermostats. As of current it is the only thing that controls the heating (except for the heater's own protection thermostat which shuts off if the water inside gets too hot or pressure too high). Once again, most helpful! Thank you!

 

[stem]

Ah OK, if you don't have a timeswitch then it will be fine. I actually have one of these controlling some electric heating in my conservatory, I only bought it because it was the only one I could find with the capacity to switch more than 2 or 3 amps. It has worked well for the past 12 months, but it took me a while to get proficient at programming it.

Here in the UK these units are becoming quite popular, probably because of their price, and I have come across two installations where there has been interference from a unit in a neighbouring property. So, if you have close neighbours, then I would recommend changing the frequency settings in case they have the same unit or get one in the future.

 

[Toshe]

Ah OK, if you don't have a timeswitch then it will be fine. I actually have one of these controlling some electric heating in my conservatory, I only bought it because it was the only one I could find with the capacity to switch more than 2 or 3 amps. It has worked well for the past 12 months, but it took me a while to get proficient at programming it.

Here in the UK these units are becoming quite popular, probably because of their price, and I have come across two installations where there has been interference from a unit in a neighbouring property. So, if you have close neighbours, then I would recommend changing the frequency settings in case they have the same unit or get one in the future.

Honestly, thank you so very much. I have already read about most of this but it's certainly nice that you have mentioned it. I doubt I will have interference, I think few people here are informed enough about these things but none the less I will keep that in mind ^^

 

[apollocreed]

The Salus RT500RF is designed to control both the temperature and the time, of a central heating system only. (e.g. a combi boiler that doesn't require hot water time control) It should be continually powered, so if your existing thermostat is powered via a timeswitch / programmer elsewhere, it's not really quite what you need.

Old mechanical thermostats are not always accurate, and get worse as they wear and age. If you do have time controls elsewhere, I would seriously consider just swapping the old thermostat for a new accurate digital wired one. The link you your existing thermostat even states it has a 1 to 2 degree accuracy. Appalling.

However, if you do decide to install the Salus, and bypass any existing central heating time control, then for a 230 VAC system, the Salus should be wired as follows:

1) Live will be the incoming live supply (presently to terminal 1) This should be a permanent live, and not controlled by a timeswitch elsewhere.

2) Live should also be linked to the COM. This provides a live supply to the Salus internal contacts, which, when the device is 'on'...

3) ...will energise the NO terminal which is the switched live supply to the boiler (presently to terminal 2) to turn it on.

4) Neutral is self explanatory. (presently to terminal 3)

Regarding the link, the drawings provided by Salus are typical only, but if you look at the table at the bottom of page 6 in your manual, you will see that it says COM = Linked Live feed (230V AC heating applications only)

I am a bit concerned about your lack of basic electrical understanding, the table on page 6 of the Salus instructions, along with the details you have given above, provide you with all of the information you require.

Hi, I already bought this Salus RT500RF for £27 on Amazon and then I realised that it doesn't control the hot water. Would you recommend me returning it and buying something like the Drayton LP722 or is there a digital programmer that I can buy that will work with this and allow me to set the hot water to a timer? Thanks.

 

[stem]

Hello apollocreed and welcome to the forum.

Much depends upon what controls you have now.

As you have figured, you can't use the RT500RF to control the hot water, it is only a programmable room thermostat. However, if you have an existing two channel programmer, you can use the Salus to control the central heating and leave the existing programmer to control the hot water.

The Drayton LP722 is only a programmer, but would still need a separate room thermostat

There are other systems that include a programmer and a thermostat in a single package, such as Nest and Hive, but to install them yourself you need quite a high level of electrical knowledge and skill as well as an good understanding of central heating systems and their associated components.

For future reference, you should start a thread of your own with a new question rather than tag it on an existing one. This is known as hijacking and is against 'Forum Rule 6' However, as you are a newbie I'm sure it will be OK just this once.

 

[apollocreed]

Hello apollocreed and welcome to the forum.

Much depends upon what controls you have now.

As you have figured, you can't use the RT500RF to control the hot water, it is only a programmable room thermostat. However, if you have an existing two channel programmer, you can use the Salus to control the central heating and leave the existing programmer to control the hot water.

The Drayton LP722 is only a programmer, but would still need a separate room thermostat

There are other systems that include a programmer and a thermostat in a single package, such as Nest and Hive, but to install them yourself you need quite a high level of electrical knowledge and skill as well as an good understanding of central heating systems and their associated components.

For future reference, you should start a thread of your own with a new question rather than tag it on an existing one. This is known as hijacking and is against 'Forum Rule 6' However, as you are a newbie I'm sure it will be OK just this once.

Thank you for your reply. Sorry for breaking the rule. I'll be careful in future. I have an old mechanical programmer installed that uses pegs for setting the timer. It's very old and the numbers are fading. The thermostat is a wired-in plastic dial in the corridor which is the coldest part of the house. Unfortunately, the boiler has begun to run continuously and never shuts off unless I turn off the power switch, so my first theory is to change the programmer. Is there any point to changing the programmer and then also using the Salus instead of the wired in thermostat?

 

[stem]

If your existing thermostat is working OK then just change the programmer. Wireless thermostats are OK but their main advantage is that the installer doesn't have to run a cable to the thermostat, but as yours is already there it's not an advantage for you.

The thermostat should be in the last part of the house to get warm, in order to make sure everywhere is up to temperature before it shuts the heating down. Hopefully your other rooms will have thermostatic radiator valves to stop them overheating.

You don't give any details of your system, if it is an old system with gravity hot water and pumped central heating that requires you to have the hot water set to be 'on' to get heating then you will need a suitable programmer. However, if yours is a more modern fully pumped system with motorised valves any two channel programmer will be OK.

IMHO good makes include Danfoss, Drayton and Honeywell.

However, you should do a bit of fault finding before changing the programmer. There are other more likely causes of the boiler staying on, depending on your system.

1. If your system does have motorised valves, the programmer and thermostats will control the motorised valves, but it's the motorised valves that actually control the boiler. It is quite likely that a motorised valve has a sticky microswitch that is keeping the boiler running. I would estimate that 90% of the time a boiler runs continuously, that this is the cause.

2. A faulty / incorrectly set frost thermostat if you have one.

 

[apollocreed]

Thank you very much. I'll look into it. The heating can run without hot water, so I assume it's run by motorised valves. I had a gas engineer do a service last week and he suggested that the thermostat on the copper cylinder might be malfunctioning, but he said it could be any number of things.

 

[stem]

If the cylinder thermostat has failed in the 'on' position it would keep the boiler going continually only until the hot water goes 'off' at the programmer, at which point the boiler would still stop, because it would no longer have a live supply to it. It wouldn't be running 24/7

If you do have motorised valve(s) then even if the programmer were faulty, the room and cylinder thermostats would still stop the boiler running when they were up to their set temperature.

The only way to find the cause is to switch off the heating and the hot water, then trace back where the live supply to the boiler is originating from. But it requires a multimeter and a fair bit of electrical competence, to isolate the individual components while testing.