Bosch Greenstar Controllers

[John Molyneux]

It looks like Bosch has some new controllers that look like an intelligent complement to the ODR and FW200 boiler control. Does anyone have any experience with them or understand how they work, and if they might be worth trying?

This is all I can find, from their brochure....

"Controllers

Bosch offers comfort room controllers that can be used in single or multizone applications, similar to conventional on/off thermostats in style and use but provide additional energy savings and comfort.

u CZM100: Three zone control module, for circulator pumps or zone valve activation. The sleek, compact zone control module is expandable up to three modules providing a maximum of 8 heating zones. It features external front facing LED lights for operational visibility

u CRC200: Programmable controller with an integrated temperature sensor can be used as a boiler control or in conjunction with the CZM100 as a room controller. It features a time program for space heating and indirect hot water tank and has warm weather shutdown capability when used with an optional outdoor sensor

u CRC100: Integrated temperature sensor with basic thermostat functions can be used as a boiler control or in conjunction with the CZM100 as a room controller

 

[John Molyneux]

I found a brochure that has some more information:

"NSC and Energy Savings

When actual room temperature is less than what the thermostat is set for, a request is sent to fire the boiler. In a conventional On/Off system the boiler is always firing at its maximum output.

Installing a Bosch boiler with the NSC, the controller measures the room temperature and uses intelligent proprietary two way communication to tell the Bosch boiler the exact needed output temperature.

If the difference between the actual room temperature and the thermostat set temperature is small the NSC requests the boiler to run at a smaller output range to supply just what is needed. This increases comfort by avoiding temperature swings and decreases the boiler water temperature, leading to lower energy costs when compared to conventional on/off control systems."

The brochure also says this avoids the need for "complicated outdoor reset curves."

So I guess this is an indoor reset approach that modulates the boiler based on room temp? Is there any reason that would be better than regular outdoor reset?

 

[Sponsor]

 

[Dana]

It certainly models the instantaneous load requirements better. At 0F outdoor temps there can be a significant difference in actual load depending on whether there is high sun on a calm day with good direct & reflective solar gain vs. at night with a gale force wind. Air temperature alone is a pretty crude model of heat load, but way better than nothing.

With an indoor smart-sensing control it figures out within a few minutes if it's losing ground vs. gaining (and how quickly) a the current output water temperature and adjusts accordingly, to always modulate the output temp in a narrow range around what is actually needed, which buys you a percent or three of average fuel efficiency with a mod-con, and delivers VERY stable room temperatures.

 

[John Molyneux]

So you'd assume that it would modulate just as effectively as outdoor, with a focus on relatively steady state operations? And I guess I'm confused about whether you'd have any control over water temps if the brain in the thermostat is doing everything.