Danfoss CP715 Si programmer and RET230-P thermostat

[dpm_dpmartin]

I had a Tenant leave a rented property on Thursday... usually we'd do a face-to-face Check-Out but that's impossible right now, so I went there yesterday (Sunday). All is good apart from the central heating - for some reason I cannot get it to work. I am hoping someone might be able to steer me with my problem determination.

It seems he's one of those guys that turns everything OFF - everything, including the fridge freezer and the boiler... so I turned all the stuff back on again, I prefer to just leave things running. Whatever I did I could not seem to get the radiators hot. This property isn't new to me, so it should be easy (or so I thought).

On the Danfoss programmer I would usually hit the +1HR button for CH to do my test - I did, I didn't pay much attention, but I heard the IDEAL boiler fire up, 20 minutes later, stone cold radiators.

Slightly bemused I checked the Danfoss thermostat in the hallway just in case - and it was down at its lowest... I was pondering whether that would have an effect, or not, wasn't I overriding the thermostat with the +1HR? So I just ramped it up to maximum anyway, and carried on...

20 minutes later, stone cold radiators... I checked the boiler - sure enough, the big blue burner light was on and it was rumbling away. Stone cold radiators. I went to the cylinder room and there was plenty of rumbling in there. And some of the pipes were also hot... so it definitely seems as if the boiler is burning gas and creating heat. I checked the TRVs on each radiator - some were down, but certainly not all... I ramped them up anyway.

I started to wonder if some valve wasn't switching or something... in the cylinder cupboard there are 2 valves I can see, looking like this:

And they're both on AUTO - the 'choices' being AUTO or MAN - not something like OPEN and CLOSED. I didn't see either move - should I?

Anyway, the only strange thing I've noticed is that the hallway thermostat does not "click" as you turn it - I always knew you would hear a click as you moved the dial - as it switched on and off - whatever range you spin the dial - no click. That doesn't seem right to me, but I'm not even sure if the programmer overrides it anyway... so if I've set +1HR there and I move the dial up and down, maybe it won't click because the programmer is saying ON no matter what?

After about half an hour... I could see a drip start to come out of the black plastic overflow visual opening in a pipe... (which I think means things are hot and being asked to get hotter, so expanded water needs to escape?)... so I turned everything off for the time-being and left.

I'm going back today... everything is switched OFF.

If I move the hallway thermostat to lowest level, then I turn everything ON and let it settle down, if I ramp up the thermostat to maximum (leaving the programmer alone - or must I set it to AUTO, as it'll be OFF?), should I hear a click and hear and see the boiler kick-in, then - after a while - should the radiators get warm?

Should I see one of the valves in the cylinder cupboard change position or stay at AUTO? If I don't, is there something wrong with one?

If I don't hear a click from the thermostat is there something wrong with it?

If I just focus on the programmer and press +1HR again, is that actually the master device for the control of the boiler and CH, and it doesn't matter what I do with the hallway thermostat?

I really appreciate any advice here... the first time I have to do a socially distanced Check-Out and something seems to go awry, and I'm not there with the Tenant to prove it's happened.

As I say, I'm going back today, so I can take whatever pictures help, and do what I'm told.

 

[CBW]

Wow that’s a lot of info. Ok a couple of things: post photo of hallway thermostat, check the heating valve in the cylinder cupboard, are the pipes hot to and from it? You probably won’t see anything on valve move, but you should hear the motor opening. The boiler, is this firing for heating or hot water?

 

[sircerebus666]

The timer (+1h) does not override the wall thermostat it simply switches on the heating for an extra hour

To test the heating , turn on the heating at the timer there should be an option for on, turn the thermostat fully up and turn all the trvs upto full and wait

Make sure you haven't turned on the hw by mistake.

If no hot rads after a while then yes you have a problem , that's when you start groping pipes to see where the heat stops , probably at the manifolds which you should be able to override and check by turning on

To be honest if you don't know that a timer doesn't override a wall thermostat or that the timer must be on even if you turn up the thermostat then you don't know how a heating system works and therefore if you don't know how it works you can't fix it and can make things worse by fiddling

If you can't get the heating on this afternoon simply call out an heating engineer

Have you spoke to your previous tenant to ascertain if it worked or not?

 

[dpm_dpmartin]

Here's the hallway thermostat...

Good to know I'll not see anything move on the valve... I do at home, if I press the programmer's 1 hour boost equivalent button at home I can see the lever slide across in front of my eyes. I will check the pipes and report back.

I have hot water - yes - I pressed the 1HR+ button for hot water and I had hot water when I checked... whether that was from before or not, I cannot say. Sorry.

 

[dpm_dpmartin]

To test the heating , turn on the heating at the timer there should be an option for on, turn the thermostat fully up and turn all the trvs upto full and wait

Make sure you haven't turned on the hw by mistake.

I can do that, then I suppose I can turn both to ON and wait?

If no hot rads after a while then yes you have a problem , that's when you start groping pipes to see where the heat stops , probably at the manifolds which you should be able to override and check by turning on

Well, I feel (pun intended) I can grope stuff as good as anyone else out there!

To be honest if you don't know that a timer doesn't override a wall thermostat or that the timer must be on even if you turn up the thermostat then you don't know how a heating system works and therefore if you don't know how it works you can't fix it and can make things worse by fiddling

Trust me, this is noted - but it's been so well-behaved for years I figured this must be something quite simple and I was looking more for validation of my thoughts I suppose.

Have you spoke to your previous tenant to ascertain if it worked or not?

Absolutely - no problems whatsoever he says - been there almost 2 years. I've asked him what he turned OFF in detail, just so I could backtrack his steps and I did not find he'd done something funny in the cylinder cupboard or what-have-you... it's quite peculiar. I wish he'd not gone around turning everything off and we could've done a normal Check-Out as I'm pretty sure this problem would not have arisen.

I really have no idea. The heating was working fine all 18 months I lived there. Never had a problem with it.
The only thing I've done is put the temperature knob to lower temperature in the morning, and once I cleaned up the place I've change setting from 'manual' to 'off'. All the lights were off, and that 1 hour boost button wasn't on.
I'm really not sure, maybe it's been off for couple days, but on the other side it shouldn't effect it. I was away for some time sometimes and that didn't caused an issue.
I even had heating off in the summer months for months and that was fine too.

 

[dpm_dpmartin]

Just a question to fill in a gap inside my brain...

This hallway thermostat measures temperature, right? That's what it does.

And, as you turn the dial, if you ask for a temperature higher than it is measuring, you will hear a "click" (inside it, like an immersion heater) as it switches and as it calls for heat, right?

Even if there's no boiler at the other end (theoretically) should you still hear that "click" happen as you dial it up from minimum to maximum?

 

[dpm_dpmartin]

And... a completely different thing, more light-hearted... this programmer from Danfoss must've been installed in about 2010... and the manual proudly states that the time is pre-set at the factory and there's no reason to alter it...

But the fact is - in 2020 it's now 6 minutes out from the real time! Nothing is perfect, right? But do I now set the time on the oven to match it, or to reality? It would be nice to reset this time somehow. Secret mode... by holding a button down for 5 seconds or something...

 

[sircerebus666]

Just a question to fill in a gap inside my brain...

This hallway thermostat measures temperature, right? That's what it does.

And, as you turn the dial, if you ask for a temperature higher than it is measuring, you will hear a "click" (inside it, like an immersion heater) as it switches and as it calls for heat, right?

Even if there's no boiler at the other end (theoretically) should you still hear that "click" happen as you dial it up from minimum to maximum?

You are correct in that a thermostat measures temperature although the dial ones are not the most accurate of things

However the click all depends on the thermostat some are quite noisy when they click some are very quiet

Don't turn on the hw just the heating and if the boiler fires when you call for heating then you know the thermostat is working , you can also turn it down whilst the boiler is firing to see if the boiler shuts down , it's a little crude but it's a good indication

Think you should complain to danfoss about the timer being out 6 mins in 10 years - the horror!

 

[dpm_dpmartin]

Think you should complain to danfoss about the timer being out 6 mins in 10 years - the horror!

On this - it's not about it being out - all clocks will lose or gain some over time... but most would allow you to re-sync. them.

 

[sircerebus666]

https://www.google.com/url?sa=t&sou...FjABegQIBRAB&usg=AOvVaw1SFWW4dZhNcD6qMLu8Q7ZE

Page 7 (just call me Cher)

 

[dpm_dpmartin]

This is the result of my testing yesterday, I didn't get back until late or I would've written this last night.

From everything OFF and hallway thermostat down at 0, radiators stone cold, I turned the boiler on, waited a little bit, then turned the thermostat up to maximum and then set the CH on the programmer to ON. This was indicated on the programmer by a red light on the left-side and ON shown on the LCD. But, no, the boiler didn't fire-up... the blue burner light on the boiler did not come on.

I then altered the temperature knob on the boiler, increasing it, and the boiler burner light came on. Nothing happened with the radiators though - still cold. I went up to the cylinder cupboard and there were noises in the there. The two pipes I've marked 1 and 2 were both hot, the radiators were not.

Plus, after a while, water started to exit the overflow pipe...

I turned everything OFF properly and thought about it for a bit. (???) I then turned the boiler back on, I left the boiler temperature a bit lower and the programmer OFF for CH and HW (no LEDs) and I altered the position of the valve I've highlighted in 3 above - from AUTO to MAN - and within less than 5 minutes the radiators were warming-up... in 10 minutes they were hot.

The boiler burner light also came on.

When I moved the valve's lever back to AUTO, the boiler burner light went off.

 

[dpm_dpmartin]

https://www.google.com/url?sa=t&sou...FjABegQIBRAB&usg=AOvVaw1SFWW4dZhNcD6qMLu8Q7ZE

Page 7 (just call me Cher)

Now that, right there, is value-add!!! I will give it a go... now the oven and the programmer can be truly in sync...

Unless I have to now replace the programmer? I can't believe it's working... not properly... it is from the front (LCD, LEDs, buttons etc.) but it doesn't feel like it's doing what it should at the back?

Unless the valve has gone, seems unlikely, right?

I want it to be the programmer, I took it off the wall and had a look - it's just 4 wires, and there's no wiring you need to do - it just notches onto a backplate. I could get a new one, copy the jumper settings and be on my way... maybe? I don't want to spend £100 buying the wrong part to replace. What a dilemma!

 

[dpm_dpmartin]

https://www.google.com/url?sa=t&sou...FjABegQIBRAB&usg=AOvVaw1SFWW4dZhNcD6qMLu8Q7ZE

Page 7 (just call me Cher)

P.S. - I'd like you to know that I do have the User Instructions for this device - mine is different to yours - mine is 2 pages and it clearly says - "The time and date are set in the factory and do not need to be set."

 

[dpm_dpmartin]

So, gents, does this sound like the programmer is kaput and, if so, should I replace it like-for-like (about £60)... or shall I get something newer that fits onto the same standardised(?) backplate?

 

[dpm_dpmartin]

Only to close this off... I had the programmer replaced, but also an actuator in one of the zone valves.