SR868C8 Solar Controller problem, can anybody offer some help?

[shapecontractor]

Hi, Have a solar system not working. The SR868C8 is flashing up a T1 fault. From the manual, I understand this is a PT1000 sensor problem on the panel array. I did a continuity test by disconnecting the sensor from the controller and got an OL reading. From the manual I would have expected around a 1000 ohms. I then thought I would put a link across the T1 terminal on the controller and would have expected the fault to clear but unfortunately T1 fault still flashed up? I then thought that this might be because the controller would be looking for some kind of resistance across the sensor? Can anybody offer some technical advice on this please?

Regards

Jim

[Mike90250]

Who manfactuers the SR868C8 ? I've never heard of it.

Is this a solar PV panel, or a thermal heat panel ? Solar PV has no "sensor" on the array. Often a thermal sensor is placed at the battery to provide proper charge setpoints.

[shapecontractor]

Mike, its a thermal panel evacuated tubes. T1 (PT1000 sensor) sits in the thermal pocket on the roof. I didn't do the install but looked briefly at it for client of mine. I googled SR868C8 solar controller and believe it's an import of chinese origin? Client luckily had the manual and this is luckily available online also.. There's also an SR868C8Q that has two sensors for two panels but my interest is the SR868C8 which only has one panel.

[shapecontractor]

http://sunpeakusasolar.com/manuals/SR868C8%20Controller.pdf

[LucMan]

Hi, Have a solar system not working. The SR868C8 is flashing up a T1 fault. From the manual, I understand this is a PT1000 sensor problem on the panel array. I did a continuity test by disconnecting the sensor from the controller and got an OL reading. From the manual I would have expected around a 1000 ohms. I then thought I would put a link across the T1 terminal on the controller and would have expected the fault to clear but unfortunately T1 fault still flashed up? I then thought that this might be because the controller would be looking for some kind of resistance across the sensor? Can anybody offer some technical advice on this please?

Regards

Jim

Sounds like your sensor is either open or has a broken wire to sensor. Check for splices in the wire & or wire nuts.
You should never short out the terminals, use a 1000 ohm resistor or any size that corresponds to a temperature in your chart to check the controller.
The good thing is that PT 1000 sensors are readily available.

[shapecontractor]

Lucman thanks. Sensor is definitely open but I just wanted to check that on purchasing a sensor I would then find that the controller was faulty also. Client has just moved into new property with fitted solar thermal which was switched off. When she switched on the fault code appeared straight away. Looks like previous owner knew but possibly wanted to hide it. Thanks for tip about the downfall of putting in a link. I'll get hold of a resistor and re-try. range in booklet is 1000-1460ohms 0-120 deg C. Would the following resistor be correct to satisfy the controller just to see that it's functioning correctly? I'm thinking that a 1.3k resistor = 80 deg C so should be sufficient?

http://cgi.ebay.co.uk/10-x-1-3K-Ohm-0-25w-Metal-Film-1-4w-Resistor-1-1K3-/120534769594?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c106e9fba

thanks Jim

[LucMan]

Lucman thanks. Sensor is definitely open but I just wanted to check that on purchasing a sensor I would then find that the controller was faulty also. Client has just moved into new property with fitted solar thermal which was switched off. When she switched on the fault code appeared straight away. Looks like previous owner knew but possibly wanted to hide it. Thanks for tip about the downfall of putting in a link. I'll get hold of a resistor and re-try. range in booklet is 1000-1460ohms 0-120 deg C. Would the following resistor be correct to satisfy the controller just to see that it's functioning correctly? I'm thinking that a 1.3k resistor = 80 deg C so should be sufficient?

http://cgi.ebay.co.uk/10-x-1-3K-Ohm-0-25w-Metal-Film-1-4w-Resistor-1-1K3-/120534769594?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c106e9fba

thanks Jim

that will work

[LucMan]

Who manfactuers the SR868C8 ? I've never heard of it.

Is this a solar PV panel, or a thermal heat panel ? Solar PV has no "sensor" on the array. Often a thermal sensor is placed at the battery to provide proper charge setpoints.

They are manufactured in China by Shaungri for ST use.

http://www.shuangri.com/en/about.asp

[jk494]

T1 not reading

I have the same problem T1 will not register, tried swapping sensors but still no T1 reading.
How did you solve your problem?

[Thermal John]

I have the same problem T1 will not register, tried swapping sensors but still no T1 reading.
How did you solve your problem?

Sounds like your sensor wire may have a short. I find it happens alot on the cheaper stainless steel piping line sets with integrated sensor wire (some actually have it on the inside of the insulation right against the pipe wall) One good period of stagnation and the wire will melt if flow is re-established pushing the heat down the line before the system cools down. you will see a reading on an ohm meter but it will be much, much lower than it should be while the controller will not recognize it at all.

[jk494]

Only one problem with that diagnosis, I dont have integrated hose and sensor cable. They are both completly different.

Have since found that if I connect 2 sensors in parrallel I get a reading but with just one i get blank! Reading is low though around 42'

[LucMan]

I have the same problem T1 will not register, tried swapping sensors but still no T1 reading.
How did you solve your problem?

Check controller first, follow the post, above using resisters. If you then get a reading the problem is in the sensor or wire.

[jk494]

I have two PT1000's that give no readings on channel T1, connect either to another channel and I get a reading that indicates the sensors are good. Pair them up in parallel and I get a reading on T1 of about 1/2 what i would expect, use them on individually get no reading.

Seems to think that the controller is kaput, even though its brand new?