Greenstar Heatslave II External and a Honeywell Home T3..?

[topcat888]

Hi everyone, I hope someone can shine some light on my problem, I've pulled most of my hair out so far..! I moved recently and inherited a Greenstar Heatslave II External boiler which in turn is controlled by an old Build Centre 7 day timer and a Honeywell BDR91 Relay Box wired into CH circuit. Basically I thought I would buy a Honeywell T3 wireless with the intention to simplify and better control the boiler, however when I wired up the T3 as per instructions, the boiler will not fire up on either HW or CH... I have attached the original wiring in Build Centre timer for reference. When the original CH/HW triggers (as shown) are put into the correct terminals of the Honeywell T3, the controller works as intended (goes on and off) however the boiler does nothing, neither HW nor CH..?


Any pointers would be much appreciated....

 

[CBW]

Ok, a bit of confusion in the post.

• Did you purchase a T3 or T3R?
• Is your intention to control heating and hot water with the new Honeywell?

 

[topcat888]

Hi Chris, I purchased the T3R... The inetention was to replicate what was there already, i.e. constant 24hr HW demand together with timed CH...

 

[CBW]

Right topcat,

You need to keep the existing build center timer, as the Honeywell T3R is for heating control only (I can explain the wiring if this is what you want?). If your looking to upgrade the build center and room thermostat, then you need something like the Honeywell T6R-HW, which does the two. There are other devices capable of this as well.

 

[topcat888]

Ah, now I'm confused as in the T3R instructions it shows what looks like both CH and HW connections for a combi boiler..? Yes, if you could explain the wiring that would be much appriciated, just so I can understand...

Yes, the ultimate goal was to swap out the old build center one for a newer more intellengent controller with a remote thermostat...

 

[CBW]

Ahh, so is it a combi boiler you have? I’m not au fait with oil boilers.