Flat Heating Potterton Promax SL & EMP 2 Controller

Tojo_Ralph

I am wondering if anyone can advise on an issue with heating in a one bedroom flat that appears to relate to the EMP 2 Controller.

Boiler is a Potterton Promax SL and heats 4 thermostat controlled radiators and hot water. The controller is an EMP 2 and there appears to be no thermostat other than on radiators.

The system works "fine" when the controller is not playing up, but even when left on 24 Hrs it keeps going lights out and not coming back on. If I remove the EMP 2 from the backplate and refit it, then it seems to fix it temporarily.

So from what I can see I can buy replacement digital/LCD models with the SAME backplate and fit to change out simply, although compatibility is unclear?


Also, can a new controller with the same backplate and some kind of thermostat built into it? As it stands it seems the timer and radiators control the boiler?


Thanks in advance.

thorganby

There are many programmers that will fit onto the existing BG EMP 2 standard backplate.

You can check compatibility here:

https://www.draytoncontrols.co.uk/sites/default/files/D70-9%20-%20Compatibility%20Guide.pdf

Programmer prices vary considerably but you should be able to get a suitable replacement for £25 e.g.

https://www.ebay.co.uk/itm/Honeywell-ST9400A-24-hr-2-channel-programmer-Replace-Landis-RWB2-Miniminder/293312934130

It would be possible to add a programmable thermostat to your system, allowing you to program different temperatures for different time periods throughout the day however it's not something that you would be able to do yourself if asking this question about your programmer.

southcoastrgi

LP522 5/2 day programmer
LP722 7 day programmer
LP822 choice of the other two programs in one unit

All will fit straight onto your existing back plate with no wiring alterations,

You should also have a room stat but that will need wiring in

Tojo_Ralph

Both .... Thanks for the replies and FYI I went with the LP722 £45 Amazon.

I fitted it today and all appears to be well. However in an effort to understand a bit more I did some reading to establish if a Gravity system or fully pumped as controller required jumper put one way or other. I went with Gravity fed?

Also I thought I better understand how/if heating (radiators) and hot water were controlled separately. Part was because at my age I really should know the basics.

So to describe the system.

1. Boiler with small water tank above, two approx. 20mm pipes out of top plus approx 10mm (gas?).
2. Below boiler Grundfos Alpha2 15-60 and a Drayton Zone Valve Actuator.
3. Actuator is turned on/off when LP722 turns on/off Hot Water.
4. Hot water tank has small water tank above. Thermostat on pipe to/from hot water tank by tank.
5. Four Radiators with thermostats.

So I guess I am right in saying that the actuator valve controls, connects and isolates the Hot Water meaning heat and hot water can be separated? I know the controller is two channel but research suggested only a “fully pumped” system isolates heat and hot water. I appreciate the controller indicates dual channel and two are switched separately but who knows who fitted original.

Thanks in advance once again.

Lgas

Hi, from what you've described you have a fully pumped system. Is there a 22mm pipe going into the Drayton valve from the bottom and one coming out of each side of the valve?

Tojo_Ralph

Lgas wrote: »

Hi, from what you've described you have a fully pumped system. Is there a 22mm pipe going into the Drayton valve from the bottom and one coming out of each side of the valve?

Let me try and get some photos uploaded to tinternetof of wiring and set up. I checked and Original controller (sticker date 2010) was set up as Gravity fed. However, maybe worth mentioning the boiler went in maybe 4/5 years ago, so post dates controller. Maybe wiring will also help?

Wiring Controller: http://ibb.co/CmzMMhn
Area under boiler pump and actuator: https://ibb.co/zxhWkWy
Typo in Picture, this is of course Hot water tank with water tank above: https://ibb.co/y8gGZSh
Actuator with 20mm pipe bottom & top: https://ibb.co/CBLssXw
Boiler and cold water tank: https://ibb.co/Hqpr7yB

Well that was harder than I suspect it should have been .... But hopefully it explains things a bit better. There is no “room” thermostat and the only things you cannot see are the 4 radiators and the radiator style thermostat on the hot water tank. No more pumps or significant fixtures and fittings.

I did look (no way would I fiddle) at wiring diagrams and the backplate looked a bit light without wiring on 3rd and 4th terminals.

Thanks in advance as always.

Lgas

Hmm ok unless you have a second actuator somewhere, that actually looks like a C plan system (semi gravity), so I would leave the gravity link in as before.

Tojo_Ralph

Lgas wrote: »

Hmm ok unless you have a second actuator somewhere, that actually looks like a C plan system (semi gravity), so I would leave the gravity link in as before.

Thanks. So after a little reading am I correct in saying that the controller can control heating and hot water separately? Or are my choices heating AND hot water or Hot water. No option for heating only?

With regards not having a thermostat, I assume it’s the radiator and hot water thermostat that call for hot water and make the boiler kick in? No idea how that works but if system is left fully on 24/7, something must tell the boiler that things are up to temperature?

Thanks. 👍

Lgas

Tojo_Ralph wrote: »

Thanks. So after a little reading am I correct in saying that the controller can control heating and hot water separately? Or are my choices heating AND hot water or Hot water. No option for heating only?

With regards not having a thermostat, I assume it’s the radiator and hot water thermostat that call for hot water and make the boiler kick in? No idea how that works but if system is left fully on 24/7, something must tell the boiler that things are up to temperature?

Thanks. 👍

On a gravity setting you cannot have the heating on by itself, it's an old fashioned system with a modern boiler so really it should have been upgraded to fully pumped when the boiler was installed. Without a thermostat the only heat control is the boiler thermostat, so when the boiler reaches it's set temperature it will shut down, cool, then come back on again until you turn the heating off. A good option would be to have a wireless thermostat fitted which would be much more efficient at regulating the house temperature.

Tojo_Ralph

Lgas wrote: »

On a gravity setting you cannot have the heating on by itself, it's an old fashioned system with a modern boiler so really it should have been upgraded to fully pumped when the boiler was installed. Without a thermostat the only heat control is the boiler thermostat, so when the boiler reaches it's set temperature it will shut down, cool, then come back on again until you turn the heating off. A good option would be to have a wireless thermostat fitted which would be much more efficient at regulating the house temperature.

Long term I am going to look at the wireless thermostat deal which I assume will require a professional.

Having left the heat and water on, replacing the controller seems to have fixed the original issue. That said, the place is boiling hot with radiators cranked down to 1. So I took the cover off and looked at the “flow temperature adjustment screw" which was cranked up to a dead stop at max!! So with no markers or numbering, on a scale from 3 o’clock to 1 o’clock, I set it a 7 o’clock. Not sure what it should be as google references temperatures. Thanks.

Tojo_Ralph

So with the heating better but still somewhat hot, I turned the boiler flow temp adjustment screw down a little bit more and will see where it goes. One thing I noticed is that with the heating on continuous and things a niceish temp, the boiler seems to come on for only maybe minutes every maybe 10 mins and there’s always a tricking sound from the boiler when it does. I assumed a boiler would sit idle longer. I took some pics of complete boiler and pipe work with cover off and will post when I get a moment. Thanks.