Sunvic Select 207XL programmer, hot water but no heat

eko

Hey guys,

Coming into the colder days now, I tried to fire up the heating through the ageing Sunvic Select 207XL programmer we have installed. Hot water has worked flawlessly but now I cannot get the heating to work. The programmer lights up on the heating side as before, signalling that the heat is programmed on, but the radiators don't heat.

I'm certainly no expert, so went to look at the pipes and there seem to be three actuators that control the two heating zones (downstairs and upstairs, simple enough). If I manually move the actuators to another position, I get heat in the radiators. However, doing this I also found that the heating would come on even if the programmer is set to have heat off but have water on, which kind of means that the heating of hot water is also heating the rads.

I also checked the two wall thermostats (older style rotary type, no displays) and both are set to 20c.

(I've set the actuators back to the way they were now, so back to no heating.)

Sorry for the numpty question here, but what might possibly be the issue here, so that I can contact the correct professional? Could it be a Sunvic programmer issue? A thermostat issue? Or possible the actuators themselves?

Thanks for any help you guys can give me.

K.Flyer

eko wrote: »

...
what might possibly be the issue here, so that I can contact the correct professional? Could it be a Sunvic programmer issue? A thermostat issue? Or possible the actuators themselves?

It could be either one of them.
Try turning the thermostats up full for a start.
It is relatively easy to check each of them to work out where the problem is.
But because both heating actuators are affected, I'm betting on it being the programmer.

You can call either a plumber or an electrician, as long as they understand heating controls

eko

K.Flyer wrote: »

It could be either one of them.
Try turning the thermostats up full for a start.
It is relatively easy to check each of them to work out where the problem is.
But because both heating actuators are affected, I'm betting on it being the programmer.

You can call either a plumber or an electrician, as long as they understand heating controls

Thanks K.Flyer. I tried with both thermostats on max, but still no joy. If I turn the hot water off at the programmer and turn on only the heating, the boiler doesn't fire either, which seems to suggest the programmer I guess. Does the programmer control the actuators I have on the pipes directly? Or is there likely to be another diverter valve nearer the boiler? The actuators are upstairs in the hot press, the boiler is downstairs.

Good to learn more about how this works before seeking a professional. Thanks again for the help.

K.Flyer

A simple explanation. .
Pressing switch on timer sends power to the stat, if stat is on (calling for heat) it forwards power to zone valve actuator and turns the valve to open. As the actuator opens the valve there is a micro switch inside the actuator which gets switched on. This switch will either send power to the boiler to fire or bridge a volt free contact in the boiler to make it fire.

eko

K.Flyer wrote: »

A simple explanation. .
Pressing switch on timer sends power to the stat, if stat is on (calling for heat) it forwards power to zone valve actuator and turns the valve to open. As the actuator opens the valve there is a micro switch inside the actuator which gets switched on. This switch will either send power to the boiler to fire or bridge a volt free contact in the boiler to make it fire.

I'm looking to source a replacement Sunvic Select 207 XL programmer, but it seems these are now rare (and by the looks of the comments online, prone to failure).

The Honeywell ST9400C seems to be a compatible replacement and seems easy enough to install by modest electrical skill standards. Anyone else use this programmer and recommend it?

One question here; I'm fully with the idea that, being both heating actuators not firing, the likely culprit would be the programmer - what if the stats themselves were somehow both faulty? That would also mean both actuators won't fire, right?

K.Flyer

The easiest way to figure if its the programmer is to remove the programmer from the mounting plate, identify the wires for hot water and heating, swap them around and refit the timer.
Then press the button for hot water and if all is good with the rest of the wiring, the stats and actuators the heating should then come on.
Horstmann would be a reliable replacement.
P.s. remember to isolate electricity before removing and during working on the back plate connections.

chief robert

Hi Eko,

I think I'm in exactly the same boat today as you were back then. My Sunvic Select 207 XLS is getting into a cycle of turning itself on and off when both the Central Heating and Hot Water are timed to be ON at the same time. This wasn't the case previously but having read up online - alot of people had the same issue.

I also saw the Honeywell ST9400C appeared to be a compatible replacement.

Did you go with that Timer, and if so - did you wire it yourself? I'm reasonably competent in wiring and electrics, but I haven't installed a timer before so am just not sure I'm going to get a surprise when I remove the Sunvic?

Also - did you change the Thermostats as well in the rooms (I think thats what you were considering also)?

Thanks,

Rob

eko wrote: »

I'm looking to source a replacement Sunvic Select 207 XL programmer, but it seems these are now rare (and by the looks of the comments online, prone to failure).

The Honeywell ST9400C seems to be a compatible replacement and seems easy enough to install by modest electrical skill standards. Anyone else use this programmer and recommend it?

One question here; I'm fully with the idea that, being both heating actuators not firing, the likely culprit would be the programmer - what if the stats themselves were somehow both faulty? That would also mean both actuators won't fire, right?

Mcelroa3

eko wrote: »

Hey guys,

Coming into the colder days now, I tried to fire up the heating through the ageing Sunvic Select 207XL programmer we have installed. Hot water has worked flawlessly but now I cannot get the heating to work. The programmer lights up on the heating side as before, signalling that the heat is programmed on, but the radiators don't heat.

I'm certainly no expert, so went to look at the pipes and there seem to be three actuators that control the two heating zones (downstairs and upstairs, simple enough). If I manually move the actuators to another position, I get heat in the radiators. However, doing this I also found that the heating would come on even if the programmer is set to have heat off but have water on, which kind of means that the heating of hot water is also heating the rads.

I also checked the two wall thermostats (older style rotary type, no displays) and both are set to 20c.

(I've set the actuators back to the way they were now, so back to no heating.)

Sorry for the numpty question here, but what might possibly be the issue here, so that I can contact the correct professional? Could it be a Sunvic programmer issue? A thermostat issue? Or possible the actuators themselves?

Thanks for any help you guys can give me.

Hi Eko, sorry for reigniting an old thread but I have the same heating system and the exact same problem as you had with it, hot water is heating but it doesn't heat the radiators anymore. Would you be able to tell me what the problem was with yours in the end and how you got it sorted please?

Thank you,

Andrea