Hi there,

I have installed a Bosch solar kit in a hybrid system comprising a solar water heater and a backup gas geyser.  This thermostatic temperature control system works well, but the factory setting is 45° C. This is way too cold for me. 

Does anybody know how to adjust the temperature of this mixing device? I can see two adjusting nuts, one each on the two control valves, but I have no idea about how to use them. Google is not much help either :)

Any help would be appreciated.

23 minutes ago, Marcb said:

Hi there,

I have installed a Bosch solar kit in a hybrid system comprising a solar water heater and a backup gas geyser.  This thermostatic temperature control system works well, but the factory setting is 45° C. This is way too cold for me. 

Does anybody know how to adjust the temperature of this mixing device? I can see two adjusting nuts, one each on the two control valves, but I have no idea about how to use them. Google is not much help either

Any help would be appreciated.

Hi Marc

 

Post some pictures please.

27 minutes ago, Marcb said:

Hi there,

I have installed a Bosch solar kit in a hybrid system comprising a solar water heater and a backup gas geyser.  This thermostatic temperature control system works well, but the factory setting is 45° C. This is way too cold for me. 

Does anybody know how to adjust the temperature of this mixing device? I can see two adjusting nuts, one each on the two control valves, but I have no idea about how to use them. Google is not much help either

Any help would be appreciated.

It seems 45° C is what it does.

got this from https://www.specifile.co.za/news/bosch-thermotechnology-the-bosch-solar-kit/

"

Using the Bosch Solar Kit means you can connect your existing hot water installation to either a solar water heater with gas back-up or only add a gas back-up to an existing electrical geyser without having to purchase any special solar appliance.

It avoids unnecessary on/off cycles as well as accidental scalding at the tap by ensuring that hot water is supplied at 45 degrees, irrespective of whether the incoming water was too hot or too cold, by pre-mixing the water.

It optimises your solar water heater by ensuring you have hot water, but will avoid unnecessary gas ignition due to a unique bypass function, which allows the water to bypass the gas water heater all together if the water is already hot enough."

Hi Antony,

The pamphlet I got with it also says "Adjusting thermostatic valves: The thermostatic valves included in the solar kit come sealed and are both preset to 45°C. Should you wish to modify these settings, please contact a qualified technician".

I tried to find a knowledgeable technician here and also contacted Bosch in Germany. Dead ends both ways.

I believe the valves use heat sensitive springs and the way they are adjusted by moving the nut is pretty obvious. I just do not know which way to turn each one to obtain a temperature increase and also keep both valves "synchronised".

I will try to post photos.

7 minutes ago, Marcb said:

I believe the valves use heat sensitive springs and the way they are adjusted by moving the nut is pretty obvious. I just do not know which way to turn each one to obtain a temperature increase and also keep both valves "synchronised".

Be careful that this does not void the warranty.

 

I have the same problem. Because the geyser is now installed further away from the point of consumption, the heat losses en route decrease the 45°C water too much and the water is not warm enough at the point of use.

 

From my research the Bosch solar kit can be adjusted to deliver a water temperature between 35°C and 55°C. You do this by adjusting the 2 valves simultaneously. The factory setting of 45°C works off an assumed hot water temperature of 65°C and an assumed cold water temperature of 15°C. I suppose the Bosch kit mixes the water in a ratio of 60 hot:40 cold to achieve an output temperature of 45°C. It is set at 45°C to prevent scalding (I suppose in Europe one cab not feel that the water is too warm and people burn themselves???) I think the valves simply adjust the flowrates as I cannot see how the temperature is sensed. I am not at this stage sure how too adjust but plan to use trial and error.

See attached presentation which may be helpful.

final-product-info-solar-kit.pdf

Yes Herman, it's the same kit. I have obtained a phone number from Bosch for their South African Solar Energy Team. Will try next week. Other wise, as you said, it will be trial and error.

Well, that phone number was another dead end. I never got one piece of useful information from Bosch so I will need to be creative 😒

On 2018/10/12 at 6:40 PM, Marcb said:

Well, that phone number was another dead end. I never got one piece of useful information from Bosch so I will need to be creative 😒

Ever managed to get anywhere with this?