The Efficient Home Forum

HI,

I have three zones in my setup, two are UFH rooms with Zone Valves and thermostats. The Third is for the remainder of the house, within which i plan to install HR92's in some of the rooms.

I have also installed a stored hot water ATF500 sensor and this is controlled by a pump connected to a BDR91.

I currently have a boiler relay configured (BDR91), which demands heat from the boiler and (importantly) this in turn triggers the main heating pump.

All works ok, except that when the hot water fires, it also turns on the main house heating. Presumably if i had HR92's on every radiator that would be ok. However, because i have only some installed, then it is warming the main house through the summer.

So my question is.... Can i configure a BDR 91 and associate it to the various HR92's in the same way as i do with a UFH Zone Valve. If yes, then i can use this to drive the main heating pump and still have a Bolier Relay configured which fires the boiler (only).

Thanks in advance!

Do you have zone valves for the 3rd circuit or is the zone valve locked open?

Hi,

Thanks for the response. I have a zone valve on the third (main house circuit) and this is configured as the "Bolier Relay" in EvoHome. The end switch on this zone valve triggers the boiler to fire. This Zone valve opens each time the hot water on, hence my problem. I would like to be able to open the zone valve based on the HR 92's.

Thanks.

Hi,
I had a similar problem with my set up. The problem lies with using the bdr91 as a boiler relay. You need to change this setting to boiler control NONE. Then rebind hr92s and it will give you the option at the end to rebind the heating bdr91 as a valve actuator. Remember to clear any previos binding. It may also prompt you to reconfigure your hot water set up. I have a 2 zone set up heating and hot water. When my hw came on it in turn fired up the heating bdr91until i made this change.

The control application you are trying to achieve is not possible... The rads would need HR92's fitted to all of them and the system configured as a 'Figure 4' system for this to work...

Barnaclebill wrote:Hi,
I had a similar problem with my set up. The problem lies with using the bdr91 as a boiler relay. You need to change this setting to boiler control NONE. Then rebind hr92s and it will give you the option at the end to rebind the heating bdr91 as a valve actuator. Remember to clear any previos binding. It may also prompt you to reconfigure your hot water set up. I have a 2 zone set up heating and hot water. When my hw came on it in turn fired up the heating bdr91until i made this change.

Hi Barnacle, with your recommendation it seems that one can use a Y plan system with HR92s and bind the HR92s with the BDR91 as a valve actuator on the heating circuit. Does this work?
Currently it seems that only a figure 4 works and a figure 3 with HR92s is not possible. Is this correct?

This is a big question for a lot of people I am sure.

There are a few factors here, but most things are possible.

You can control a Y Plan system with HR92's on all radiators and bind this through the hot water guided configuration (2x BDR91 - 1x heating demand and 1x as hot water demand). This only works with a gas boiler and if you had oil, you would neeed a 3rd relay for boiler demand (so cycle rate can be adjusted to suit oil).