Do I need a HCC80R for my UFH

[lewisst]

Hi Experts,

I'm hoping someone one can guide me in right direction as in SW London getting a plumber on the Honeywell list is impossible, closest I've got is one picked up phone and said he would call me back, that was a week ago!

In my previous house I had a Evohome throughout, 2 zone UFH controlled by a HCC80R and the upstairs controlled via HR92's and this worked lovely. I just moved and in my new house I have 1 big zone UFH controlled by a Heatmeister and radiators everywhere else controlled by a Honeywell thermostat. After giving up on the callback from the professional and a few 100 calls to others I've changed the rads to all have HR92's and swapped the relay box front (lucky the old system used the same relay so didn't have to rewire). This works amazing well and is as good as my old place! The issue is we want to control the UFH as well but it looks to me like the Heatmeister control takes a Live+neutral from the wiring box and returns a grey (switched live?) which seems to activate the pump, UFH valves and motor valve input to the manifold (this doesn't work well so we have locked it open). These seem hard wired in the wiring box. I can't see any way for the UFH to activate the boiler so it seems to me to piggy back the rads doing this for it.

In order to get the UFH controlled by the Evo home controller and the heatmeister controller gone, do I need a full blown HCC80R or could I just emulate what the heatMeister is doing with another relaybox? signal output replacing the grey wire (switched live) from the heatmeister then program the kitchen as thermostat == a DTS92E1020 and valve == the relay box?

Hope this makes sense and if anyone knows a plumber in SW London let me know as I'd love to outsource this job but also need it working for xmas.

thanks.

[Richard]

SW London this time of year you'll be very lucky. I do know some good guys though.

If its a single UFH zone, you can use a Y87RF instead of a HCC80R.

[lewisst]

Thanks for the advice, we did this with some parts from my old Evohome installation (Fools who bought our old house wanted lost taking out for a Nest!) and it worked! That said, I think while we got the wiring correct, we messed up the setup. The heating engineer did the following, he installed the BR92 taking a live and neutral, cross wiring the live to A and a switched live to B. Then in the App we created a new Zone and used the Evohome monitor itself as the thermostat and bound the BR91 as a heating type "Zone Valve" and this worked almost perfectly. I say almost as it did work, the signal came on, opened the Zone valve, started the UFH pump and signaled the boiler so the UFH worked as expected. The only issue was the Evohome system also powered on the first BR91 which controls the radiator circuit so every time the UFH comes on both the rad and ufl circuits are opened (this is a one way thing as the rad circuit does not turn on the ufh and manual turning on the ufh does not turn on the rads).

My guess is the way we have set up the zone wrong somehow and evohome it thinking it's needs to fire up the original br91 to fire up the boiler as well as the 2nd br91 to open the valve when all it needs to do is fire up the 2nd br91 as that has a parallel wire to fire up the boiler. It's not a big deal I guess as the rooms have the thermostats but a part of me is nagging away constantly saying we have got something wrong and this is not optimal!

[gada]

you could try the following

stop the UFH zone activating the rad pump by configuring it as “electric heat” so it will not activate the the appliance control (boiler) BDR91

remove the boiler wire from the appliance control BDR91 leaving it controling only the rad pump

add another BDR91
take the boiler wire removed above to contact A and live to contact B
this now it becomes the boiler control BDR91

bind the new BDR9 as a second appliance control and also bind it as a second BDR91 on the UFH zone


the new BDR91 will come on if the rads or the UFH demand heat and will power the boiler,
the original BDR91 also comes on with the rads but not the UFH and controls the rad pump


think it is what you wanted !

[Richard]

Thanks for the advice, we did this with some parts from my old Evohome installation (Fools who bought our old house wanted lost taking out for a Nest!) and it worked! That said, I think while we got the wiring correct, we messed up the setup. The heating engineer did the following, he installed the BR92 taking a live and neutral, cross wiring the live to A and a switched live to B. Then in the App we created a new Zone and used the Evohome monitor itself as the thermostat and bound the BR91 as a heating type "Zone Valve" and this worked almost perfectly. I say almost as it did work, the signal came on, opened the Zone valve, started the UFH pump and signaled the boiler so the UFH worked as expected. The only issue was the Evohome system also powered on the first BR91 which controls the radiator circuit so every time the UFH comes on both the rad and ufl circuits are opened (this is a one way thing as the rad circuit does not turn on the ufh and manual turning on the ufh does not turn on the rads).

My guess is the way we have set up the zone wrong somehow and evohome it thinking it's needs to fire up the original br91 to fire up the boiler as well as the 2nd br91 to open the valve when all it needs to do is fire up the 2nd br91 as that has a parallel wire to fire up the boiler. It's not a big deal I guess as the rooms have the thermostats but a part of me is nagging away constantly saying we have got something wrong and this is not optimal!

Just trying to confirm you only have 2x heating zones (one radiator circuit and one UFH circuit) and no HR92's? If so both need to be bound into the evohome Controller as a 'Zone Valve' zone and there should be no 'Appliance Relay' set. At the moment you have an appliance relay set (installer menu > system devices) and it is operating the rad circuit each time you have radiator and UFH demand.