Best position for Resol S4 sensor

[alankelly]

Hi everybody.

Does anybody know please the best position for the S4 sensor that is required for heat quantity measuring, using a RESOL BS / 4 type controller? 

Should it be mounted on the return pipe just after the store return or just before the collector panel inlet?

Many thanks in advance and best regards Al.

[forever green]

S4 should be positioned on the return pipe from the cylinder, try to get it within a couple of feet away at the most . make sure it is secured to the pipework and then cover it with insulation to ensure the most accurate reading. Also ensure that the correct flowrate is set on the controller...factory default is 6lpm which is too high for domestic systems.

[KLD]

If the "other" thermal sensor for the heat meter is embedded in the flow meter, then it would be nice to put S4 also into a more direct contact with the fluid. I've made up some Ts with embedded short pieces of stopped 8mm copper tube for this purpose. It still needs decent insulation wrapped all around to ensure that you really measure the fluid temperature. The difference between flow and return will only be a few degrees C, so 1 degree inaccuracy in one sensor can translate to 20% or more inaccuracy in the heat meter.

Klaus
 

[alankelly]

Hi everybody

Thanks for the advice

I will try to mount the sensor on the outside of the brass drain cock using heatsink paste, a clamp and covering heavily in armaflex insulation (Drain cock is about 3" from the tank outlet) to prevent heat loss

I would have mounted it futher down on the return pipe, but it is twinsol, so as it is ribbed, so surface contact heat transfer may cause very inaccurate measurement, as I guess if the drain cock is heavy insulated and as brass is good conductor of heat, after a short period of time the outside of the brass drain will be about the same temperature as the return fluid, and as it is very close to the tank there will be very little temp' drop in the fluid I am sensing from the tank

Also flow has been set at the usual 2l / min so will set this flow rate also for the controller.

Does that make sense?

Ps the system was a cheap DIY install so not RHI compliant but I was just curious about how much heat (roughly) I was collecting

Best regards and many thanks Al

[BORIS]

Al
A Question for you.
How are you controlling your excess energy / thermal dump ?
With 25 tubes and a 150 L tank, you will have boiling water on sunny days or if you go away.
I have 30 tubes to 150 L in NE England, my Resol BS plus in arrangement 3 allows T4 as only a temp sensor because Relay 2 is being used to control my heat dump when the cylinder reaches 75C.
I decided that the energy calculation was not necessary especially when I have to dump heat occassionally (very rarely during 2011 !).
Regards

30x58mm into 150l twin coil Newark
8 x 250 sanyo with Enecsys 240 inverters
7 kW WBS
2 national hives but no bees yet

[alankelly]

Hi Boris

To control my excess energy during the summer, I have used Antmans solution where once the store reaches 65C, relay 2 on the Re-sol controller operates a relay that does 3 functions

First it operate the CH pump, then it sets the 3 way DHW / CH diverter valve to mid position, and finally it inhibits the boiler firing so basically the boiler coil removes the excess from the store and dumps it into the rads around the house.

I only installed the system myself late this year (Early September) so I shall see how the system performs in 2012, (Even this year during that week in late september when we had 5 days of lovely sunshine the system performed really well and the boiler did not come on at all to heat the DHW) and if necessary if the house becomes too warm, I have as plan B, a  two position diverter valve already fitted in the solar circuit so if necessary I can add an external heat exchanger to dump the excess to the outside.

Lastly the reason for going for a 25 58 tube collector to a 150l store was that due to the position on the garage roof, As I have a PV array on the main room I have a shading issue.

See

http://www.navitron.org.uk/forum/index.php/topic,15186.msg170073.html#msg170073

So from around 2.30 mid summer, the collector starts to become shaded and is fully shaded by around 6.00, so I went for an oversize collector to collect as much thermal heat as possible from sunrise to around 2.30 then the system will start to collect less from this time onwards

See

http://www.navitron.org.uk/forum/index.php/topic,14405.msg161451.html#msg161451

for more on my shading issue

Interestingly in the winter on sunny day the shading issue is far less and the panel is fully exposed to around 4.00 due to the sun being lower in the sky.
 
Best and kindest regards Al.