Can anyone help. My heating central heating timer has 3 x on and off programable time settings for both the heating and water. The Water will go on and off on all three times set but my central heating will only come on and go off, on the 1st time set - which is the early hours of the morning. The central heating will not come on for the either the 2nd time which is set for the afternoon and nor the 3rd time, which is due to come on in the early evening. Any ideas as gto what the problem could be???
The programmer is a Honeywell ST6400C. I have a Grundfos pump and a Honeywell V4073A 3 port valve. If i move the lever on the valve over to manual position myself, then yes, the heating will come on. I was wondering whether the valve could be faulty, or wouldn't it keep coming on in the morning if there was a problem with the valve? What do you think? Still the programmer? Is it possible that the programmer will work on every other time, except the second and third heating programmed times? Thanks for your help so far! Samantha
If you've got a thermostat or roomstat on your system try turning it up. It may be that the heating only comes on in the morning when the house is at its coldest, and dosn't come on later because the house temp is higher than the thermostat setting
Hi Htg engineer,
Yes, if i move the lever on the honeywell V4073a 3 port valve to manual, the heating comes on. Is it possible it could be the programmer given that it works fine for the hot water and for the heating first thing?? Could it be the valve itself not working properly? Apologies if you get this twice. My last message to you seems to not have appeared.
Thanks for your help! Samantha
Without touching the Actuator, if you select Central Heating on the programmer (on manual/ ON/ All Day, not on timed) does the heating come on ?
As you say the heating works on a morning - that would suggest the actuator and everything else is working fine. That's why I said it may be the programmer.
Hi Htg,
Yes, without touching the actuator and with the heating set to continously on on the programmer, the heating comes on when the digital thermostat in the hallway calls for heat and goes off once the temperature has been met. Does that mean it is the prgrammer then ? And do you think its something thats easily repaired or am i better off just buying a new programmer? Thanks again for your help! Samantha
Hi Htg, after sending my last message to you, the heating has now decided not to come on at all when the thermostat in hallway is calling, despite still being switched on to the constant setting. Do you think this is just another way of the programmer playing up? Or could it be another problem lurking? Thanks so much. Hope you dont mind me asking another question! Thank you, Samantha
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!
by samantha » Fri Sep 19, 2008 12:01 pm 
