Hot water problem : Delta sol temp vs tap/shower temp

mileycactus

Hi hoping someone can help / seen similar hot water issue

We have the delta sol with solar panel for hot water. Usually I can read S3 on the panel to tell me the temp of hot water at top of tank and whether it needs a quick boost off the gas. All fine during the hot summer but now with less sun the water only seems lukewarm even with S3 temps in the 50’s (it’s set to max out at 60deg from factory settings). The last few years anything from 40deg plus was fine for a shower but as low as 35deg would do. Now if it gets to mid 40’s it’s cold. When I boost with the gas it heats up fine and we have hot water but the S3 reads 60deg and but the water ain’t exactly piping hot.

Also I notice sometimes the hot water starts piping hot and then cools which suggests the temp sensor isn’t faulty but for some reason we are not getting a full draw of the hot water from top of the tank

Any ideas before I get the plumbers involved? Any help much appreciated

John.G

mileycactus wrote: »

Hi hoping someone can help / seen similar hot water issue

We have the delta sol with solar panel for hot water. Usually I can read S3 on the panel to tell me the temp of hot water at top of tank and whether it needs a quick boost off the gas. All fine during the hot summer but now with less sun the water only seems lukewarm even with S3 temps in the 50’s (it’s set to max out at 60deg from factory settings). The last few years anything from 40deg plus was fine for a shower but as low as 35deg would do. Now if it gets to mid 40’s it’s cold. When I boost with the gas it heats up fine and we have hot water but the S3 reads 60deg and but the water ain’t exactly piping hot.

Also I notice sometimes the hot water starts piping hot and then cools which suggests the temp sensor isn’t faulty but for some reason we are not getting a full draw of the hot water from top of the tank

Any ideas before I get the plumbers involved? Any help much appreciated

You can get a very good idea if S3 is reading correctly by just pulling its sensor out of it's (dry) pocket and immersing it in a bowl/dish of hot water and note the temperature, then remove S2 (the store temperature sensor located just above the solar coil, near the cylinder bottom) and immerse this in the same bowl and compare both. Or, ideally, immerse both of them together.
If you have/had been observing both these temperatures when the cylinder was solely being heated from the solar collector then both should have read almost exactly the same, when water is being drawn off then S2 will start falling first due to the entry of cold makeup water.
You say that S3 reads 60C after gas boosting, if the cylinder stat is set at 60C then that would also indicate (roughly) that S3 is correct.
The only other thing that I can think of just now is that you have a antiscald valve fitted and that it is malfunctioning and giving you colder water than its setpoint.

Dtp1979

Yep. Faulty mixing valve I’d say

mileycactus

John.G wrote: »

You can get a very good idea if S3 is reading correctly by just pulling its sensor out of it's (dry) pocket and immersing it in a bowl/dish of hot water and note the temperature, then remove S2 (the store temperature sensor located just above the solar coil, near the cylinder bottom) and immerse this in the same bowl and compare both. Or, ideally, immerse both of them together.
If you have/had been observing both these temperatures when the cylinder was solely being heated from the solar collector then both should have read almost exactly the same, when water is being drawn off then S2 will start falling first due to the entry of cold makeup water.
You say that S3 reads 60C after gas boosting, if the cylinder stat is set at 60C then that would also indicate (roughly) that S3 is correct.
The only other thing that I can think of just now is that you have a antiscald valve fitted and that it is malfunctioning and giving you colder water than its setpoint.

Thanks a million. Got the plumber in today, faulty mixer valve replaced and hot water is back to normal.