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Andrew Smith
Andrew Smith, HVAC Technician
Category: HVAC
Satisfied Customers: 3646
Experience:  Heating and Controls engineer
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i have a honeywell st9100a controller. When i used to press

Customer Question

i have a honeywell st9100a controller. When i used to press the 1 hour function button it used to come on by making a littel click noise, this would them switch my heating on but now when i switch it on the 1 hour it doesnt make the click noise but the green light comes on but my heating upstarirs does not work, the radiators do not warm up. Even when i put continuous on it still does not work even though the green light comes on the honeywell.
I have a st9400 which controls the downstairs heating which is working fine.
Can someone please help
Submitted: 3 years ago.
Category: HVAC
Expert:  Andrew Smith replied 3 years ago.

Andrew Smith :

It sounds like the ralay inside the controller has broken.

Andrew Smith :

Are you looking for a direct replacement (does this do the job adequately for you)?

Andrew Smith :

You can get a new one from here;

Andrew Smith :

http://www.ebay.co.uk/sch/sis.html?_nkw=Honeywell%20Timer%20St900A&_itemId=190833290227