Hi, am new to the forum so please treat me gently!
I have a Honeywell ST7100 programmer circa late 80's/early 90's that makes a continual buzzing noise during the timed periods. The central heating function has now ceased to work (Brrrr!) but fortunately I can still get hot water. Having removed it to see if anything could be done to kick start it back into life, it appears that the buzzing is probably coming from what looks like two relays on the printed circuit board that I suspect are probably defective. Given the age of the unit, I beleive renewal is the best (or only!) option. I have unconfirmed reports that Honeywell units share a common backplate mount that means later models may be installed without rewiring as a straight new-for-old swap. Can anyone tell me please if this is true and if so, what modern day equivalent (i.e. model type/number) I could fit in place of the old one? Current one has three permissible time setting options for CH and HW during the day which I would like to keep if possible.
Many thanks in advance of your interest and advice.
I have a Honeywell ST7100 programmer circa late 80's/early 90's that makes a continual buzzing noise during the timed periods. The central heating function has now ceased to work (Brrrr!) but fortunately I can still get hot water. Having removed it to see if anything could be done to kick start it back into life, it appears that the buzzing is probably coming from what looks like two relays on the printed circuit board that I suspect are probably defective. Given the age of the unit, I beleive renewal is the best (or only!) option. I have unconfirmed reports that Honeywell units share a common backplate mount that means later models may be installed without rewiring as a straight new-for-old swap. Can anyone tell me please if this is true and if so, what modern day equivalent (i.e. model type/number) I could fit in place of the old one? Current one has three permissible time setting options for CH and HW during the day which I would like to keep if possible.
Many thanks in advance of your interest and advice.
