Honeywell programmer problem - no CH and HW at same time

[fezster]

Very strange problem this evening, and I'm thinking most likely a programmer fault. It's a honeywell ST9400C. I usually have it with the heating on continuous (controlled by a programmable thermostat) and hot water to come on for an hour in the morning, and override as required. It's connected to 2 x 2 port zone valves - one for heating, one for HW.

Noticed tonight that the hot water has remained cold, despite pressing the "+1 hour button" a couple of times. After some investigation, it seems the programmer will either call for the heating OR the HW, but not both together. The light comes on for both, but the *click* only happens on the first which is switched on. I distinctly remember it *clicked* for both CH and HW (though i could be mistaken).

Is this most likely a programmer problem? Any simple checks I can do? Any other ideas?

Thanks.

 

[TCCHeating]

It's the programmer. Known fault with the st9400c. I have stopped installing them because i have had so many problems with them.

 

[muggles]

ST9400Cs had a dodgy batch, the new ones are apparently OK so it should be a five minute straight swap

 

[TCCHeating]

ST9400Cs had a dodgy batch, the new ones are apparently OK so it should be a five minute straight swap

The new ones are just as bad. Believe me! The failure rate on these is unacceptable. Honeywell don't want to know unless it was in the dodgy batch. I remember reading somewhere that an electronics lecturer took one apart and said his students could design a better one in a few hours. Cheap relays apparenty

 

[fezster]

Thanks guys. Looks like only one output switches on at any one time. Checked with a multimeter. Both on, and only one live! Switch other off, and it goes live.

 

[fezster]

Which programmer would you recommend? I leave my heating on continuously (controlled by programmable thermostat) and only program the hot water. But we use the +1 hour functionality. What would be a reliable programmer? Is the Drayton any better reliability wise? I can get an LP722 from screwfix by 10pm, so would appreciate a quick response. Many thanks.

 

[JohnD]

.

 

[TCCHeating]

I fit the drayton mitime programmers now. Fitted about 10 since I ditched honeywell. Not had any problems so far but it's too early to tell really.

 

[fezster]

Mitime T721R fitted. Nifty looking. Let's hope it lasts longer than 2 years. Thanks again for quick responses.