Hello all... My Honeywell ST799 Programmer is problematic! I can no longer use HOT WATER alone, but only the CENTRAL HEATING programme switches on th e boiler. Also, when I attempt to programme in the time for either the HOT WATER OR CENTRAL HEATING the times change for both simultaneously! Has an yone else come across this 'delinquent' behaviour? Or can anyone suggest a fix? Any advice will be much appreciated... Richard.
It has possibly got its knickers in a twist. Remove the battery and short the terminals in the programmer to discharge any capacitors. replace battery and reprogramme.
Might work?
You need to tell us a bit more about your system. Is it fully pumped, or gravity HW and pumped CH? Does it have any motorised valves? If so, how many and what type (two port or three port)?
I could be wrong, but as far as I can see from the data sheet for your programmer, it only has one timer, so you can't have different times for HW and CH. You can independently set each to on, off or timed but, when timed, the both go on and off at the same time. Is this not correct?
My hunch is that you probably have a fully pumped S-Plan system with two
2-port motorised valves. If the boiler isn't coming on for HW, this usually means either that the HW zone valve isn't opening - or that it *is* opening but not enough to trigger its micro-switch to switch on the boiler. [I've just had this problem with my CH valve].When the boiler runs for the CH, does the HW also get hot?
Tried googling your problem?
nger use HOT WATER alone, but only the CENTRAL HEATING programme switches o n the boiler. Also, when I attempt to programme in the time for either the HOT WATER OR CENTRAL HEATING the times change for both simultaneously! Ha s anyone else come across this 'delinquent' behaviour? Or can anyone sugge st a fix? Any advice will be much appreciated... Richard.
Hi Roger and thanks for that... Bob Minchin suggests that it may have it's knickers in a twist BUT I think it might be MY knickers that are in a twis t :-)
We have only been in this house for a few days and I'm trying to get to gri ps with the heating / HW system and I'm finding it most frustrating and try ing! Ignorance kills!! When the boiler runs for the CH, the HW does also g et hot, and it does appear to be a fully pumped system but I can't identify any motorised valves. You are also correct in that the system has only on e timer and I've misunderstood the instruction booklet thinking that one ha d independent time control of the HW AND CH!? If I had a brain... I'd be d angerous... So, for me back to the learning curve...
Kindest regards... Richard.
Any chance of uploading some photos of your system somewhere, and posting a link here? [Boiler & connecting pipework, Pump, Hot water cylinder and connecting pipework, etc.]
longer use HOT WATER alone, but only the CENTRAL HEATING programme switches on the boiler. Also, when I attempt to programme in the time for either t he HOT WATER OR CENTRAL HEATING the times change for both simultaneously! Has anyone else come across this 'delinquent' behaviour? Or can anyone sug gest a fix? Any advice will be much appreciated... Richard.
it's knickers in a twist BUT I think it might be MY knickers that are in a twist :-)
grips with the heating / HW system and I'm finding it most frustrating and trying! Ignorance kills!! When the boiler runs for the CH, the HW does al so get hot, and it does appear to be a fully pumped system but I can't iden tify any motorised valves. You are also correct in that the system has onl y one timer and I've misunderstood the instruction booklet thinking that on e had independent time control of the HW AND CH!? If I had a brain... I'd be dangerous... So, for me back to the learning curve...
Hello again Roger... Well, we moved into this house just a few days ago bu t yesterday I spoke with the previous owner who explained that I was using the system incorrectly. He explained in detail how the hot water storage a nd supply tank operated in conjunction with the immersion heater. So, I di d everything as the previous owner described and all appears to be well. W e obtained hot water and enjoyed our first bath / shower since moving in :- ) ...Thank you for your help and encouragement Roger.
Kindest regards,
Richard.
Hi Richard,
Glad to hear that you're sorted.
I wouldn't recommend using an immersion heater as the principal means of generating hot water, though, if there is an alternative of using the gas boiler. Unless you're only heating it at night, with an off-peak supply, electricity is at least three times as expensive as gas for the same amount of energy.
As a matter of interest, whereabouts in the country are you?
o longer use HOT WATER alone, but only the CENTRAL HEATING programme switch es on the boiler. Also, when I attempt to programme in the time for either the HOT WATER OR CENTRAL HEATING the times change for both simultaneously! Has anyone else come across this 'delinquent' behaviour? Or can anyone s uggest a fix? Any advice will be much appreciated... Richard.
e it's knickers in a twist BUT I think it might be MY knickers that are in a twist :-)
to grips with the heating / HW system and I'm finding it most frustrating a nd trying! Ignorance kills!! When the boiler runs for the CH, the HW does also get hot, and it does appear to be a fully pumped system but I can't id entify any motorised valves. You are also correct in that the system has o nly one timer and I've misunderstood the instruction booklet thinking that one had independent time control of the HW AND CH!? If I had a brain... I' d be dangerous... So, for me back to the learning curve...
o but yesterday I spoke with the previous owner who explained that I was us ing the system incorrectly. He explained in detail how the hot water stora ge and supply tank operated in conjunction with the immersion heater. So, I did everything as the previous owner described and all appears to be well . We obtained hot water and enjoyed our first bath / shower since moving i n :-) ...Thank you for your help and encouragement Roger.
Hi Roger... Yes indeed... Got that... Location is Tollerton, near Nottingh am NG12 4DZ. I have been most grateful for your kind help and encouragemen t... It's been a pleasure to meet with you in 'cyberspace' ;-)
Kindest regards... Richard.
Not sure I?d call a gas fired system that still requires the use of an immersion heater as ?well?. It?s a very poorly designed system if it?s still reliant on a secondary heating system to provide a basic service like hot water.
Tim
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.